More on Top Tier gasoline

[Built_Well]

Usually I get 24 miles to the gallon for stop-and-go city
driving with the '06 Camry LE, but this last tankful I got
28 city. I really babied the accelerator pedal this time
and, of course, have plenty of air in the tires. I had
Shell V-Power premium in the tank this time (for its
exceptional detergent levels), but usually I just put in
a regular grade.

I had Hy-Vee Grocery Store premium in there two tankfuls
back, and thought the car was idling kinda rough sometimes
while stopped, so I thought some Shell V-Power was in
order to help clean out any minute amounts of potential
gunk I might have gotten from the Hy-Vee gas.

When I asked him, the Hy-Vee manager said his gas met
the Top Tier standard, but Hy-Vee is not on the list
of Top Tier stations at toptiergas.com, so I doubt
Hy-Vee is Top Tier.

On Hy-Vee, the car once idled at only 600 rpm; I've never
seen it idle so low. Usually 650 to 700 is the lowest it'll
idle at. It could have been a coincidence that the one 600
idle happened under Hy-Vee.

Quoting the Break Time page at the MFA Oil web site:

"TOP TIER Gasoline is a new class of gasoline with enhanced
detergency. It meets new, voluntary deposit control standards
developed by four automotive companies - BMW, General Motors,
Honda and Toyota - that exceed the detergent requirements
imposed by the EPA.

"TOP TIER Gasoline keeps engine parts cleaner by reducing
fuel-related deposits, resulting in better performance.
A lower level of detergent may cause a buildup of deposits on
critical engine parts. These deposits can cause stalling,
rough idling, lowered acceleration and other unnecessary
problems in your vehicle--and your life.

"TOP TIER Gasoline:

* Improves fuel efficiency
* Prevents driving upsets (rough idle, hesitation, stalling
and surge)
* Improves acceleration
* Provides more power
* Reduces emissions
* Cleans dirty engines and keeps new engines clean

MFA Oil Company is proud to join industry leaders by requiring
TOP TIER Gasoline with higher levels of detergent in all grades
and every gallon of gasoline at Break Time Convenience Stores.

Link: http://www.mfaoil.com/index.cfm?show=10&mid=14&pid=4

[Hachiroku]

Post by Built_Well
I had Hy-Vee Grocery Store premium

Ugh. This is about the same as Getty, Gibbs, Hess, etc regular.
It's usually bottom of the barrel gas.

I like my cars a lot better than that...

[Built_Well]

Post by Hachiroku

Post by Built_Well
I had Hy-Vee Grocery Store premium
========

Ugh. This is about the same as Getty, Gibbs, Hess, etc regular.
It's usually bottom of the barrel gas.
I like my cars a lot better than that...

========

That was the first and only time I'll use Hy-Vee gas.

They're regular grade is 89 octane, just like their mid-grade
and priced the same. But my car was using their 91 octane
premium. They lost a customer....good place to buy
groceries, though.

[Paul]

Post by Built_Well

Post by Hachiroku

Post by Built_Well
I had Hy-Vee Grocery Store premium
========

Ugh. This is about the same as Getty, Gibbs, Hess, etc regular.
It's usually bottom of the barrel gas.
I like my cars a lot better than that...

========
That was the first and only time I'll use Hy-Vee gas.
They're regular grade is 89 octane, just like their mid-grade
and priced the same. But my car was using their 91 octane
premium. They lost a customer....good place to buy
groceries, though.

Do you know what terminal they get their gas from?
Wonder if it is Conoco, Exxon, or Shell?

[Mark A]

Post by Paul
Do you know what terminal they get their gas from?
Wonder if it is Conoco, Exxon, or Shell?

Do you know additives they put in? They weren't the same ones used by
Conoco, Exxon, or Shell retailers.

[HLS]

Post by Mark A

Post by Paul
Do you know what terminal they get their gas from?
Wonder if it is Conoco, Exxon, or Shell?

Do you know additives they put in? They weren't the same ones used by
Conoco, Exxon, or Shell retailers.

How do you know that?

[Elmo P. Shagnasty]

In article

Post by Built_Well
I had Hy-Vee Grocery Store premium in there two tankfuls
back, and thought the car was idling kinda rough sometimes
while stopped, so I thought some Shell V-Power was in
order to help clean out any minute amounts of potential
gunk I might have gotten from the Hy-Vee gas.

More likely that the engine computer got used to the grocery store gas
than anything else. Two tankfuls isn't enough to cause THAT much
problem with deposits.

[doug]

After reviewing the list of TOP TIER Gasoline Retailers at their website,
http://www.toptiergas.com/retailers.html , I couldn't help but notice that
Valero, one of the largest independent refiners in the eastern US, was not
on the list. Here in Delaware, the Valero refinery in Delaware City was
built in the mid 1950's specifically designed to handle sour crude. It is
still in operation, providing numerous retail operations in this region,
including Shell (which IS on the list) with their gasoline.

If suppliers like Turkey Hill Minit Markets and Qwik Trip are identified as
being Top Tier gasolinr retailers, why isn't Valero? Especially if they are
supplying gasoline to companies that ARE on the list?

Post by Built_Well
Usually I get 24 miles to the gallon for stop-and-go city
driving with the '06 Camry LE, but this last tankful I got
28 city. I really babied the accelerator pedal this time
and, of course, have plenty of air in the tires. I had
Shell V-Power premium in the tank this time (for its
exceptional detergent levels), but usually I just put in
a regular grade.
I had Hy-Vee Grocery Store premium in there two tankfuls
back, and thought the car was idling kinda rough sometimes
while stopped, so I thought some Shell V-Power was in
order to help clean out any minute amounts of potential
gunk I might have gotten from the Hy-Vee gas.
When I asked him, the Hy-Vee manager said his gas met
the Top Tier standard, but Hy-Vee is not on the list
of Top Tier stations at toptiergas.com, so I doubt
Hy-Vee is Top Tier.
On Hy-Vee, the car once idled at only 600 rpm; I've never
seen it idle so low. Usually 650 to 700 is the lowest it'll
idle at. It could have been a coincidence that the one 600
idle happened under Hy-Vee.
"TOP TIER Gasoline is a new class of gasoline with enhanced
detergency. It meets new, voluntary deposit control standards
developed by four automotive companies - BMW, General Motors,
Honda and Toyota - that exceed the detergent requirements
imposed by the EPA.
"TOP TIER Gasoline keeps engine parts cleaner by reducing
fuel-related deposits, resulting in better performance.
A lower level of detergent may cause a buildup of deposits on
critical engine parts. These deposits can cause stalling,
rough idling, lowered acceleration and other unnecessary
problems in your vehicle--and your life.
* Improves fuel efficiency
* Prevents driving upsets (rough idle, hesitation, stalling
and surge)
* Improves acceleration
* Provides more power
* Reduces emissions
* Cleans dirty engines and keeps new engines clean
MFA Oil Company is proud to join industry leaders by requiring
TOP TIER Gasoline with higher levels of detergent in all grades
and every gallon of gasoline at Break Time Convenience Stores.
Link: http://www.mfaoil.com/index.cfm?show=10&mid=14&pid=4

[Pete]

Post by doug
If suppliers like Turkey Hill Minit Markets and Qwik Trip are
identified as being Top Tier gasolinr retailers, why isn't Valero?
Especially if they are supplying gasoline to companies that ARE on the
list?

It's a matter of additives which are mixed with the gasoline at a later
stage (at the distribution center). So, by adding specific
additives/detergents, a company that receives plain gasoline from Valero
can claim that their gas is "top tier". Valero choses not to include
those detergents in sufficient quantities at their retail locations,
hence they didn't make the list.

Pete

[Retired VIP]

Post by doug
After reviewing the list of TOP TIER Gasoline Retailers at their website,
http://www.toptiergas.com/retailers.html , I couldn't help but notice that
Valero, one of the largest independent refiners in the eastern US, was not
on the list. Here in Delaware, the Valero refinery in Delaware City was
built in the mid 1950's specifically designed to handle sour crude. It is
still in operation, providing numerous retail operations in this region,
including Shell (which IS on the list) with their gasoline.
If suppliers like Turkey Hill Minit Markets and Qwik Trip are identified as
being Top Tier gasolinr retailers, why isn't Valero? Especially if they are
supplying gasoline to companies that ARE on the list?

Post by Built_Well
Usually I get 24 miles to the gallon for stop-and-go city
driving with the '06 Camry LE, but this last tankful I got
28 city. I really babied the accelerator pedal this time

Hi Doug,

You have hit on a problem with sites like this. Nowhere on their web
site is the owner of the web site listed. They state that gasoline
must meet their requirements but their site doesn't list their
requirements. Could the major requirement be paying to be listed?

Most gasoline sold in any major metro area comes from just a few
refineries. The Toledo, Ohio metro area has just two refineries that
supply over 90% of the gas sold in NW Ohio. The oil companies say
that they have their own additive package that is added to the tanker
as it's filled. That may be true, I don't know. But one thing I do
know is that no gas station in my area sells bad gas. If they did,
they wouldn't stay in business.

You will get good gasoline almost anywhere you buy it so don't pay any
attention to web sites that purport to rate gasoline or oil companies.
And don't waste your money buying premium gas if your car doesn't need
it, you won't get better mileage and your car won't run better on it.

Jack

[Scott Dorsey]

Post by Retired VIP
You have hit on a problem with sites like this. Nowhere on their web
site is the owner of the web site listed. They state that gasoline
must meet their requirements but their site doesn't list their
requirements. Could the major requirement be paying to be listed?

According to the NIC, the toptiergas.com site is registered by GM.
--scott

[Retired VIP]

Post by Scott Dorsey

Post by Retired VIP
You have hit on a problem with sites like this. Nowhere on their web
site is the owner of the web site listed. They state that gasoline
must meet their requirements but their site doesn't list their
requirements. Could the major requirement be paying to be listed?

According to the NIC, the toptiergas.com site is registered by GM.
--scott

Thanks Scott. Now, what are their requirements in order to be listed?

Jack

[Tomes]

"doug" ...

Post by doug
After reviewing the list of TOP TIER Gasoline Retailers at their website,
http://www.toptiergas.com/retailers.html , I couldn't help but notice that
Valero, one of the largest independent refiners in the eastern US, was not
on the list. Here in Delaware, the Valero refinery in Delaware City was
built in the mid 1950's specifically designed to handle sour crude. It is
still in operation, providing numerous retail operations in this region,
including Shell (which IS on the list) with their gasoline.
If suppliers like Turkey Hill Minit Markets and Qwik Trip are identified
as being Top Tier gasolinr retailers, why isn't Valero? Especially if they
are supplying gasoline to companies that ARE on the list?

It is all in the additive package added to the tanker truck
after/during/before the same base gas is transferred to the trick. Same
gas, different additives.

I, for one, am not convinced that this Top Tier stuff has any meaning at all
anyway.
Tomes

[h***@h-gee.co.uk]

On Mon, 28 Jul 2008 13:02:09 -0700 (PDT), Built_Well
<***@hotmail.com> wrote:

Actually one of our car mags here in the UK have just run an article on BP
hi-grade gas & Diesel.

They state that the claims for extra mileage is true but the most convincing for
me at least is the test using an Audi V8 adapted to run one bank on regular
gas/petrol and the other bank on BP Ultimate.

They fitted cameras to the inside of the combustion chambers and the regular
fuel side is a shitty as hell and the BP Ultimate side is like a new stainless
steel sink with no deposits and sparkling clean.

You might see pics on the web "Car Mechanics" or "Kelsey Publishing"

try - http://www.kelsey.co.uk

Hugh

Post by Built_Well
Usually I get 24 miles to the gallon for stop-and-go city
driving with the '06 Camry LE, but this last tankful I got
28 city. I really babied the accelerator pedal this time
and, of course, have plenty of air in the tires. I had
Shell V-Power premium in the tank this time (for its
exceptional detergent levels), but usually I just put in
a regular grade.
I had Hy-Vee Grocery Store premium in there two tankfuls
back, and thought the car was idling kinda rough sometimes
while stopped, so I thought some Shell V-Power was in
order to help clean out any minute amounts of potential
gunk I might have gotten from the Hy-Vee gas.
When I asked him, the Hy-Vee manager said his gas met
the Top Tier standard, but Hy-Vee is not on the list
of Top Tier stations at toptiergas.com, so I doubt
Hy-Vee is Top Tier.
On Hy-Vee, the car once idled at only 600 rpm; I've never
seen it idle so low. Usually 650 to 700 is the lowest it'll
idle at. It could have been a coincidence that the one 600
idle happened under Hy-Vee.
"TOP TIER Gasoline is a new class of gasoline with enhanced
detergency. It meets new, voluntary deposit control standards
developed by four automotive companies - BMW, General Motors,
Honda and Toyota - that exceed the detergent requirements
imposed by the EPA.
"TOP TIER Gasoline keeps engine parts cleaner by reducing
fuel-related deposits, resulting in better performance.
A lower level of detergent may cause a buildup of deposits on
critical engine parts. These deposits can cause stalling,
rough idling, lowered acceleration and other unnecessary
problems in your vehicle--and your life.
* Improves fuel efficiency
* Prevents driving upsets (rough idle, hesitation, stalling
and surge)
* Improves acceleration
* Provides more power
* Reduces emissions
* Cleans dirty engines and keeps new engines clean
MFA Oil Company is proud to join industry leaders by requiring
TOP TIER Gasoline with higher levels of detergent in all grades
and every gallon of gasoline at Break Time Convenience Stores.
Link: http://www.mfaoil.com/index.cfm?show=10&mid=14&pid=4

--
Sir Hugh of Bognor

The difference between men and boys is the price of their toys.

Intelligence is not knowing the answer but knowing where and how to find it!

Hugh Gundersen
***@h-gee.co.uk
Bognor Regis, W.Sussex, England, UK

[Fat Moe]

Post by h***@h-gee.co.uk
On Mon, 28 Jul 2008 13:02:09 -0700 (PDT), Built_Well
Actually one of our car mags here in the UK have just run an article on BP
hi-grade gas & Diesel.
They state that the claims for extra mileage is true but the most convincing for
me at least is the test using an Audi V8 adapted to run one bank on regular
gas/petrol and the other bank on BP Ultimate.
They fitted cameras to the inside of the combustion chambers and the regular
fuel side is a shitty as hell and the BP Ultimate side is like a new stainless
steel sink with no deposits and sparkling clean.
You might see pics on the web "Car Mechanics" or "Kelsey Publishing"
try - http://www.kelsey.co.uk
Hugh

Post by Built_Well
Usually I get 24 miles to the gallon for stop-and-go city
driving with the '06 Camry LE, but this last tankful I got
28 city. I really babied the accelerator pedal this time
and, of course, have plenty of air in the tires. I had
Shell V-Power premium in the tank this time (for its
exceptional detergent levels), but usually I just put in
a regular grade.
I had Hy-Vee Grocery Store premium in there two tankfuls
back, and thought the car was idling kinda rough sometimes
while stopped, so I thought some Shell V-Power was in
order to help clean out any minute amounts of potential
gunk I might have gotten from the Hy-Vee gas.
When I asked him, the Hy-Vee manager said his gas met
the Top Tier standard, but Hy-Vee is not on the list
of Top Tier stations at toptiergas.com, so I doubt
Hy-Vee is Top Tier.
On Hy-Vee, the car once idled at only 600 rpm; I've never
seen it idle so low. Usually 650 to 700 is the lowest it'll
idle at. It could have been a coincidence that the one 600
idle happened under Hy-Vee.
"TOP TIER Gasoline is a new class of gasoline with enhanced
detergency. It meets new, voluntary deposit control standards
developed by four automotive companies - BMW, General Motors,
Honda and Toyota - that exceed the detergent requirements
imposed by the EPA.
"TOP TIER Gasoline keeps engine parts cleaner by reducing
fuel-related deposits, resulting in better performance.
A lower level of detergent may cause a buildup of deposits on
critical engine parts. These deposits can cause stalling,
rough idling, lowered acceleration and other unnecessary
problems in your vehicle--and your life.
* Improves fuel efficiency
* Prevents driving upsets (rough idle, hesitation, stalling
and surge)
* Improves acceleration
* Provides more power
* Reduces emissions
* Cleans dirty engines and keeps new engines clean
MFA Oil Company is proud to join industry leaders by requiring
TOP TIER Gasoline with higher levels of detergent in all grades
and every gallon of gasoline at Break Time Convenience Stores.
Link: http://www.mfaoil.com/index.cfm?show=10&mid=14&pid=4

It all depends on how you look at it. Unless you are racing or
pulling a heavy load up a hill it won't matter what the octane rating
is. Top tier refers to the additives that prevent build up of deposits,
especially on the intake valves. As far as getting extra mileage with
higher octane? I don't buy it, either the argument or the product. A
friend of mine would always by premium fuel, it ranged from 15 to 20
cents more per gallon. I suggested he try regular instead, but it
wasn't until we did the math that he tried it.
It went something like 300K miles divided by 25 miles/gal = 12K gal
times 18 cents = 2160 dollars. To me it's all about what it costs to
get a mile down the road, total expenses. Fuel, tires,insurance
repairs, maintenance. You can drive a Caddie or Lexus and it's going
to cost you more per mile, you can go to the other extreme and drive a
used tin can and get down the road pretty cheap. I've found Honda
Accords and Toyota Camerys to be a pretty good all around cars,
comfortable enough, right size enough, economical enough to get me that
mile down the road without breaking the bank. I use regular in them,
top tier regular if it's there but I don't worry all that much about
it. The EPA has standards for fuel which must be met and deposit
problems are addressed by them. I stay away from ethanol. The only
preignition or knocking I've encountered in a long time are with a
couple of lawnmowers and a motorcycle.
Quit kidding yourself, Do the math and get yourself some free money.

[Elmo P. Shagnasty]

Post by Fat Moe
As far as getting extra mileage with
higher octane? I don't buy it,

Octane is not the issue. Cleanliness of the fuel injectors and intake
valves and combustion chambers is the issue.

Get 'em clean first--either by adding an off the shelf cleaner like
Techron, or by using Shell's or BP's highest octane fuels. It's not the
octane that you're looking for, it's the EXTRA cleaners that they charge
for by putting them ONLY inside their highest octane fuels.

Your choice.

Once clean, keep everything clean--by using a Top Tier gas. Any octane
rating.

THEN you'll find that your fuel cost per mile is lower by using a Top
Tier gas than by using grocery store gas, for example.

Don't calculate mileage, calculate the true fuel cost of driving a mile.
Gasoline from a Top Tier vendor such as Shell may be a bit more
expensive to buy, but I found that in the end it costs less per mile to
use.

You can buy on price, or you can buy on value. If you buy on price,
you'll probably spend more per mile to fuel your car.

[c***@hotmail.com]

Post by Fat Moe
As far as getting extra mileage with
higher octane?  I don't buy it,

Octane is not the issue.  Cleanliness of the fuel injectors and intake
valves and combustion chambers is the issue.
Get 'em clean first--either by adding an off the shelf cleaner like
Techron, or by using Shell's or BP's highest octane fuels.  It's not the
octane that you're looking for, it's the EXTRA cleaners that they charge
for by putting them ONLY inside their highest octane fuels.
Your choice.
Once clean, keep everything clean--by using a Top Tier gas.  Any octane
rating.
THEN you'll find that your fuel cost per mile is lower by using a Top
Tier gas than by using grocery store gas, for example.
Don't calculate mileage, calculate the true fuel cost of driving a mile.  
Gasoline from a Top Tier vendor such as Shell may be a bit more
expensive to buy, but I found that in the end it costs less per mile to
use.
You can buy on price, or you can buy on value.  If you buy on price,
you'll probably spend more per mile to fuel your car.

I think you hit the nail on the head, Elmo, at least on certain types
of cars.

I've had my 98 Pontiac Grand Prix GTP for a little over ten years now,
and follow the gas mileage carefully. Using 92 octane, I will get a
full mile per gallon better than using mid-grade. Using 87 octane will
cost me 3-4 mpg, so it costs me a LOT more by using the cheaper
gasoline. The difference in acceleration is very noticeable as well.


Of course, with the 3.8 supercharged engine, the owners manual states
that premium unleaded is required, and I can see why.

Based on these experiences I would not even consider running anything
other than premium in my Trans Am.


I am curious as to what, if any, difference that running premium in my
06 GP (3.8 not supercharged) would make. I have only used 87 octane
since I bought it two years ago.

Even with gas prices as high as they are, I am tempted to try a couple
of tankfulls to see if it makes a difference.

[Edwin Pawlowski]

<***@hotmail.com> wrote in message
I am curious as to what, if any, difference that running premium in my
06 GP (3.8 not supercharged) would make. I have only used 87 octane
since I bought it two years ago.

Even with gas prices as high as they are, I am tempted to try a couple
of tankfulls to see if it makes a difference.

********************************************

My last 3 GM cars had the 3.8. No difference with the higher grades in both
performance or mileage. They are well tuned for regular it seems.

[Retired VIP]

Post by c***@hotmail.com

Post by Fat Moe
As far as getting extra mileage with
higher octane?  I don't buy it,

Octane is not the issue.  Cleanliness of the fuel injectors and intake
valves and combustion chambers is the issue.

I've had my 98 Pontiac Grand Prix GTP for a little over ten years now,
and follow the gas mileage carefully. Using 92 octane, I will get a
full mile per gallon better than using mid-grade. Using 87 octane will
cost me 3-4 mpg, so it costs me a LOT more by using the cheaper
gasoline. The difference in acceleration is very noticeable as well.
Of course, with the 3.8 supercharged engine, the owners manual states
that premium unleaded is required, and I can see why.

Well of course you'll get better mileage using the grade of gasoline
recommended by the manufacturer. That's a given. There are a lot of
reasons why this is true and almost all have to do with pre-ignition,
not with the additive package. In most cases, the premium grade will
have the exact same package as the regular grade.

Post by c***@hotmail.com
Based on these experiences I would not even consider running anything
other than premium in my Trans Am.
I am curious as to what, if any, difference that running premium in my
06 GP (3.8 not supercharged) would make. I have only used 87 octane
since I bought it two years ago.

Using a grade of gasoline that is above the manufacturer's
recommendation is a waste of money. The manufacturer knows what his
product was designed to do and what it's requirements are. You should
follow his recommendations.

Jack

[Mortimer]

Post by c***@hotmail.com

Post by Fat Moe
As far as getting extra mileage with
higher octane? I don't buy it,

Octane is not the issue. Cleanliness of the fuel injectors and intake
valves and combustion chambers is the issue.

I've had my 98 Pontiac Grand Prix GTP for a little over ten years now,
and follow the gas mileage carefully. Using 92 octane, I will get a
full mile per gallon better than using mid-grade. Using 87 octane will
cost me 3-4 mpg, so it costs me a LOT more by using the cheaper
gasoline. The difference in acceleration is very noticeable as well.

I'm interested that you say you get "a full mile per gallon better". That
suggests that you normally get results which are consistent to within a
fraction of an mpg, such that a difference between fuels is significantly
greater than the difference between successive tank-fillings on the same
fuel.

My experience, with both petrol and diesel cars, is that the variation
between one tank filling and another is about +/- 3 mpg, depending on
factors such as the type of driving (mainly urban / mainly high-speed / some
mixture of the two) and different points that different fuel pumps cut off
when they sense that the tank is full.

My figures are for filling the car to the pump cut-off point and then
running it until the tank is fairly low - typically for fillings of about 50
litres (11 gallons UK / 13.5 gallons US) and journeys of around 550-650
miles.

I've noticed a difference in the smoothness of the engine and the
acceleration between supermarket diesel and BP Ultimate diesel, though some
of this could be wishful thinking to compensate for the extra cost of BP
Ultimate - when you pay gold-plated prices maybe your brain thinks it can
see extra gold-plated performance!

[c***@hotmail.com]

Post by Mortimer

Post by c***@hotmail.com

Post by Fat Moe
As far as getting extra mileage with
higher octane? I don't buy it,

Octane is not the issue. Cleanliness of the fuel injectors and intake
valves and combustion chambers is the issue.

I've had my 98 Pontiac Grand Prix GTP for a little over ten years now,
and follow the gas mileage carefully. Using 92 octane, I will get a
full mile per gallon better than using mid-grade. Using 87 octane will
cost me 3-4 mpg, so it costs me a LOT more by using the cheaper
gasoline. The difference in acceleration is very noticeable as well.

I'm interested that you say you get "a full mile per gallon better". That
suggests that you normally get results which are consistent to within a
fraction of an mpg, such that a difference between fuels is significantly
greater than the difference between successive tank-fillings on the same
fuel.

When I say "a full mile per gallon better ", I mean that driving under
the same type driving conditons, speed, weather, pay load, highway or
city, air conditoner use, etc if I drive the SAME way, I will get one
mile per gallon better on a consistent basis. Have done so for years.
Maybe not a noticeable difference, but the higher octane gasoline is
better for my particular automobile.

Post by Mortimer
My experience, with both petrol and diesel cars, is that the variation
between one tank filling and another is about +/- 3 mpg, depending on
factors such as the type of driving (mainly urban / mainly high-speed / some
mixture of the two) and different points that different fuel pumps cut off
when they sense that the tank is full.

Of course, if I am driving 85 on the interstate, I will get less
mileage than if I am cruising at 70 (which is the speed I usually use
to test my gas mileage), even less if I slow down to 65 or so.

Post by Mortimer
My figures are for filling the car to the pump cut-off point and then
running it until the tank is fairly low - typically for fillings of about 50
litres (11 gallons UK / 13.5 gallons US) and journeys of around 550-650
miles.

I use my car's on board mileage calculator, which I have tested and
found to be extremely reliable.

Post by Mortimer
I've noticed a difference in the smoothness of the engine and the
acceleration between supermarket diesel and BP Ultimate diesel, though some
of this could be wishful thinking to compensate for the extra cost of BP
Ultimate - when you pay gold-plated prices maybe your brain thinks it can
see extra gold-plated performance!- Hide quoted text -

I feel the same way about using Shell's Premium. My car runs a little
better on it than on other brands. (At least I THINIK it does!)

Post by Mortimer
- Show quoted text -

[[e-mail]]

Post by Retired VIP

Post by c***@hotmail.com

Post by Fat Moe
As far as getting extra mileage with
higher octane? I don't buy it,

Octane is not the issue. Cleanliness of the fuel injectors and intake
valves and combustion chambers is the issue.

I've had my 98 Pontiac Grand Prix GTP for a little over ten years now,
and follow the gas mileage carefully. Using 92 octane, I will get a
full mile per gallon better than using mid-grade. Using 87 octane will
cost me 3-4 mpg, so it costs me a LOT more by using the cheaper
gasoline. The difference in acceleration is very noticeable as well.
Of course, with the 3.8 supercharged engine, the owners manual states
that premium unleaded is required, and I can see why.

Well of course you'll get better mileage using the grade of gasoline
recommended by the manufacturer. That's a given. There are a lot of
reasons why this is true and almost all have to do with pre-ignition,
not with the additive package. In most cases, the premium grade will
have the exact same package as the regular grade.

Thomas Plucinsky, BMW Product and Technology Communications Manager told us
the type and quality of additives the gasoline
companies include in the fuel. Premium gasolines may have better additive
packages which are more effective keeping fuel systems (particularly
injectors) clean and working efficiently, than those in regular grade fuels
or off-brand products. Using lower octane or off-brand fuel could be
degrading the fuel system over time, setting you up for a repair bill down
the line.

[Elmo P. Shagnasty]

Post by Retired VIP
Well of course you'll get better mileage using the grade of gasoline
recommended by the manufacturer. That's a given. There are a lot of
reasons why this is true and almost all have to do with pre-ignition,
not with the additive package.

wow, how uninformed can one person be.

Post by Retired VIP
In most cases, the premium grade will
have the exact same package as the regular grade.

And it gets even worse.

[Floyd Rogers]

Post by Elmo P. Shagnasty

Post by Retired VIP
Well of course you'll get better mileage using the grade of gasoline
recommended by the manufacturer. That's a given. There are a lot of
reasons why this is true and almost all have to do with pre-ignition,
not with the additive package.

wow, how uninformed can one person be.

Post by Retired VIP
In most cases, the premium grade will
have the exact same package as the regular grade.

And it gets even worse.

IMO, he's the one that's right and you're wrong.
http://www.state.mn.us/mn/externalDocs/Commerce/Gasoline_Octane_Facts_102902052227_OctaneFacts.pdf
and
http://dnr.louisiana.gov/sec/execdiv/techasmt/ecep/trans/b/b.htm
and
http://action.publicbroadcasting.net/cartalk/posts/list/679412.page
and
http://action.publicbroadcasting.net/cartalk/posts/list/1186410.page

All support his assertions.

FloydR

[EdV]

I hate to bring up the Direct injection thing again, but its related
to top tier gas.
True or False?
Fuels without more detergents/cleaners wont affect a direct injection
engine as much since the intake valves dont carry gasoline since the
fuel is injected via nozzles.

[Elmo P. Shagnasty]

In article

Post by EdV
Fuels without more detergents/cleaners wont affect a direct injection
engine as much since the intake valves dont carry gasoline since the
fuel is injected via nozzles.

The injectors themselves can get crudded up, so yeah, it's still
something to worry about.

[Floyd Rogers]

Post by EdV
I hate to bring up the Direct injection thing again, but its related
to top tier gas.
True or False?
Fuels without more detergents/cleaners wont affect a direct injection
engine as much since the intake valves dont carry gasoline since the
fuel is injected via nozzles.

As Elmo says, you've got to keep the injectors clean. Diesel engines
have major problems when the fuel is dirty, so I would expect similar
problems, although somewhat reduced due to gasoline's viscosity and
other problems.

However, I have seen a recent post on roadfly on the E90/92 forum
about at least one early 335i having trouble with deposit buildups on
their intake valves. Since gasoline is injected into the cylinder (rather
than intake manifold before the valves), and "bad" things are happening
as far as valve deposits:
http://forums.roadfly.com/forums/bmw/bmw_3_series_e90/8991298-1.html
As with any anecdote, caution is in order, especially since this isn't
the first direct injection gasoline engine around.

FloydR

[jim <"sjedgingN0sp"@]

Post by Floyd Rogers

Post by Elmo P. Shagnasty

Post by Retired VIP
Well of course you'll get better mileage using the grade of gasoline
recommended by the manufacturer. That's a given. There are a lot of
reasons why this is true and almost all have to do with pre-ignition,
not with the additive package.

wow, how uninformed can one person be.

Post by Retired VIP
In most cases, the premium grade will
have the exact same package as the regular grade.

And it gets even worse.

IMO, he's the one that's right and you're wrong.

Right or wrong about what?
Pre-ignition is not the same thing as knock (detonation). It is just
one of several things that lead to detonation.
Also the information you supplied is out-dated. Most modern cars have
knock sensors that adjust engine tune to avoid knock. That actually
means many cars (probably most cars) get improved mileage with higher
octane fuel even though the engine doesn't knock on lower octane fuel.
This is because the computer adjusts timing and A/F mixture in
response to the way the fuel burns. And it takes a while to learn the
ideal response. Of course better mileage doesn't mean cost efficient.
To determine that you need to weigh the higher against the actual
measured mileage.

The only way you can tell if your car (any car) gets improved mileage
with premium is to test it with different octane and different brand
fuels under controlled driving conditions. That isn't something most
drivers are able or willing to do. This is further complicated by the
fact that the main octane booster that is being used today for
gasoline in the USA is ethanol. Ethanol is added at the terminal to
the base fuel (base fuel is the same for all brands) and thus varies
from one brand to another.

From what I have read ethanol is being added to gasoline rather
willy-nilly in most places in the country. This because no one is
actually regulating or monitoring etanol usage. Spot checks by some
investigators have found huge variations in the amount of ethanol in
pumps labeled E10 (some are way too high and some way too low) and in
many places there is no labeling of ethanol content at all. So the
octane ratings at the pump are in reality a bit of a fiction.

-jim

Post by Floyd Rogers
http://www.state.mn.us/mn/externalDocs/Commerce/Gasoline_Octane_Facts_102902052227_OctaneFacts.pdf
and
http://dnr.louisiana.gov/sec/execdiv/techasmt/ecep/trans/b/b.htm
and
http://action.publicbroadcasting.net/cartalk/posts/list/679412.page
and
http://action.publicbroadcasting.net/cartalk/posts/list/1186410.page
All support his assertions.
FloydR

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[Floyd Rogers]

Post by jim <"sjedgingN0sp"@

Post by Floyd Rogers

Post by Elmo P. Shagnasty

Post by Retired VIP
Well of course you'll get better mileage using the grade of gasoline
recommended by the manufacturer. That's a given. There are a lot of
reasons why this is true and almost all have to do with pre-ignition,
not with the additive package.

wow, how uninformed can one person be.

Post by Retired VIP
In most cases, the premium grade will
have the exact same package as the regular grade.

And it gets even worse.

IMO, he's the one that's right and you're wrong.

Right or wrong about what?
Pre-ignition is not the same thing as knock (detonation). It is just
one of several things that lead to detonation.
Also the information you supplied is out-dated. Most modern cars have
knock sensors that adjust engine tune to avoid knock. That actually
means many cars (probably most cars) get improved mileage with higher
octane fuel even though the engine doesn't knock on lower octane fuel.
This is because the computer adjusts timing and A/F mixture in
response to the way the fuel burns. And it takes a while to learn the
ideal response. Of course better mileage doesn't mean cost efficient.
To determine that you need to weigh the higher against the actual
measured mileage.

The MN citation is from 2004. The cartalk forum stuff is from 2008.
Only the LA "test" was from 1991. Here's a FTC citation from 2005:
http://www.ftc.gov/bcp/edu/pubs/consumer/alerts/alt064.shtm
"At the Pump: Use the Octane Level You Need
Your owner's manual recommends the most effective octane level for your car.
For most cars, the recommended gasoline is regular octane. In most cases,
using a higher octane gas than the manufacturer recommends offers no
benefit. Unless your engine is knocking, buying higher octane gasoline is a
waste of money. "
Since most cars are tuned for 87 octane, they won't get better mileage on
91.
In fact, I have checked our Highlander and Camry ("best" performance on 89)
and it gets the same mpg on both. And our 2001 & 2007 BMWs get the same
on 91 or 87; but with significantly less power.

Post by jim <"sjedgingN0sp"@
...This is further complicated by the
fact that the main octane booster that is being used today for
gasoline in the USA is ethanol. Ethanol is added at the terminal to
the base fuel (base fuel is the same for all brands) and thus varies
from one brand to another.

Ethanol at the common 10% levels decreases our economy by about 1/2 mpg
from pure gasoline. That's about 0.5/25.0 or 2%. Ethanol is an entirely
different discussion from octane. The decreased mileage is due to the lower
energy content.

Note that both premium and regular gasoline have the same ENERGY
content (which affects mpg), even though they have different octane ratings.

FloydR

[jim <"sjedgingN0sp"@]

Post by Floyd Rogers

Post by jim <"sjedgingN0sp"@

Post by Floyd Rogers

Post by Elmo P. Shagnasty

Post by Retired VIP
Well of course you'll get better mileage using the grade of gasoline
recommended by the manufacturer. That's a given. There are a lot of
reasons why this is true and almost all have to do with pre-ignition,
not with the additive package.

wow, how uninformed can one person be.

Post by Retired VIP
In most cases, the premium grade will
have the exact same package as the regular grade.

And it gets even worse.

IMO, he's the one that's right and you're wrong.

Right or wrong about what?
Pre-ignition is not the same thing as knock (detonation). It is just
one of several things that lead to detonation.
Also the information you supplied is out-dated. Most modern cars have
knock sensors that adjust engine tune to avoid knock. That actually
means many cars (probably most cars) get improved mileage with higher
octane fuel even though the engine doesn't knock on lower octane fuel.
This is because the computer adjusts timing and A/F mixture in
response to the way the fuel burns. And it takes a while to learn the
ideal response. Of course better mileage doesn't mean cost efficient.
To determine that you need to weigh the higher against the actual
measured mileage.

The MN citation is from 2004. The cartalk forum stuff is from 2008.
http://www.ftc.gov/bcp/edu/pubs/consumer/alerts/alt064.shtm
"At the Pump: Use the Octane Level You Need
Your owner's manual recommends the most effective octane level for your car.
For most cars, the recommended gasoline is regular octane. In most cases,
using a higher octane gas than the manufacturer recommends offers no
benefit. Unless your engine is knocking, buying higher octane gasoline is a
waste of money. "
Since most cars are tuned for 87 octane, they won't get better mileage on
91.

That ignores the reality that most modern cars are tuned on the fly.

Post by Floyd Rogers
In fact, I have checked our Highlander and Camry ("best" performance on 89)
and it gets the same mpg on both. And our 2001 & 2007 BMWs get the same
on 91 or 87; but with significantly less power.

I suspect if you tested this in a truly controlled way you would find
otherwise. Drive the same route at the same rate everyday. And as said
you really don't know what is in the pump. The base fuel for regular
is 83 octane nowadays add 5% ethanol and you have 85 octane. Add 15%
and you have 89 octane. Most cars will get better mileage on the 89
octane because most cars run like crap on 65 octane, but you have no
idea what is in the pump. Yet you come up with your fantasy numbers.

Post by Floyd Rogers

Post by jim <"sjedgingN0sp"@
...This is further complicated by the
fact that the main octane booster that is being used today for
gasoline in the USA is ethanol. Ethanol is added at the terminal to
the base fuel (base fuel is the same for all brands) and thus varies
from one brand to another.

Ethanol at the common 10% levels decreases our economy by about 1/2 mpg
from pure gasoline.

OK you made that up out of mixture of thin air and wishful thinking.

Post by Floyd Rogers
That's about 0.5/25.0 or 2%. Ethanol is an entirely
different discussion from octane.

Wrong and a good indication you aren't paying attention. Ethanol is
the method of boosting the vast majority of gasoline sold in the US up
to the necessary octane level. But that assumes somebody remembered to
add the right amount. Most of the base stock fuel being produced at
refineries is too low octane for most cars on the road to run very
well and ethanol is for the most part the only available additive
that can boost the octane sufficiently and is economical and
permitted.

Post by Floyd Rogers
The decreased mileage is due to the lower
energy content.

Wrong again. Decreased mileage is usually due to very poor gas (~83
octane) that was supposed to have ethanol added but doesn't. It may or
may not be labeled as having ethanol added even though it might not
have any ethanol. Labeling at the pump is not much of an indication
because mislabeling results in no penalty and the fact is the
retailers often don't know anymore than you do about what is actually
in their tanks. So your claim that you know how much ethanol affects
your mileage is a fantasy.

Post by Floyd Rogers
Note that both premium and regular gasoline have the same ENERGY
content (which affects mpg)

Actually no that isn't true. Even if we are talking about base fuel
stocks coming from the refineries before any ethanol is added, then
premium base has usually less energy than regular base stock. Usually
it is about 3%-5% less energy in the higher octane base stock.
Look it up if you don't believe me - the API has statistics.



Even though there is less energy in high octane everyone knows there
are some cars get significantly better mileage with premium. So no you
are wrong, energy content does not predict what a vehicles mileage
will be. There is a pretty simple reason for this: The ICE used in
autos wastes around 75% of the energy content of the fuel. Therefore
how efficiently a vehicle can use a particular fuel determines mileage
not its energy content. An engine that wastes 70% of the fuel it burns
will get 50% better mileage than the same engine if it would waste
80%. And that is pretty much what the range of efficiency of most of
the engines on the road today. So the actually energy content is not
anywhere near as important as how efficiently a car can use the fuel.
And if you think octane plays no role in efficiency you simply aren't
paying attention.


At most gas stations what you get at the pump is anybody's guess
nowadays, because of a whole variety of mixing strategies that occur
at the terminals. As I said nobody is regulating this. The epa
regulates what arrives at the terminals thru the pipelines but the
states are supposed to be keeping track of where the ethanol goes. And
dealers are playing fast and loose with octane at the pump largely
because of the politics and mystique surrounding the use of ethanol.
According to the Feds more than 50% of the ethanol that is delivered
to terminals fails to show up in the reports the states are required
to make that are supposed to be keeping track of where the ethanol is
going. Again look it up if you don't believe me. The states have no
incentive to account for ethanol because ethanol is exempt from
highway taxes and thus a contributes nothing to the amount of money
the feds distribute to the states. So everybody is just like you (the
average driver) with their heads buried in the sand when it comes to
finding out exactly what it is that is coming out at the gas pumps.

-Jim





, even though they have different octane ratings.

Post by Floyd Rogers
FloydR

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[Floyd Rogers]

Post by jim <"sjedgingN0sp"@

Post by Floyd Rogers
Since most cars are tuned for 87 octane, they won't get better mileage on
91.

That ignores the reality that most modern cars are tuned on the fly.

Yes, but they are tuned for horsepower. How much HP do you use
at 70mph? It's constant; doesn't matter whether you're running 91 or 87.
And, since the energy content is the same, you'll use the same amount of
fuel.

Post by jim <"sjedgingN0sp"@

Post by Floyd Rogers
In fact, I have checked our Highlander and Camry ("best" performance on 89)
and it gets the same mpg on both. And our 2001 & 2007 BMWs get the same
on 91 or 87; but with significantly less power.

I suspect if you tested this in a truly controlled way you would find
otherwise. Drive the same route at the same rate everyday. And as said
you really don't know what is in the pump.

It varies so widely in different parts of the country, that you're bound
to be wrong. I know AS A FACT that up here in Seattle that only a
couple of brands (Arco and Union 76) have 10% in all. Others don't.

Post by jim <"sjedgingN0sp"@

Post by Floyd Rogers

Post by jim <"sjedgingN0sp"@
...This is further complicated by the
fact that the main octane booster that is being used today for
gasoline in the USA is ethanol. Ethanol is added at the terminal to
the base fuel (base fuel is the same for all brands) and thus varies
from one brand to another.

Ethanol at the common 10% levels decreases our economy by about 1/2 mpg
from pure gasoline.

OK you made that up out of mixture of thin air and wishful thinking.

No. I didn't. Seattle used to have 10% ethanal in all brands for air
pollution in Dec/Jan/Feb for ozone reduction. That's quite a long enough
period for me to get very valid numbers of before and after.

Post by jim <"sjedgingN0sp"@
Wrong and a good indication you aren't paying attention. Ethanol is
the method of boosting the vast majority of gasoline sold in the US up
to the necessary octane level. But that assumes somebody remembered to
add the right amount. Most of the base stock fuel being produced at
refineries is too low octane for most cars on the road to run very
well and ethanol is for the most part the only available additive
that can boost the octane sufficiently and is economical and
permitted.

Boy, are you not paying attention.

Post by jim <"sjedgingN0sp"@

Post by Floyd Rogers
The decreased mileage is due to the lower
energy content.

Wrong again. Decreased mileage is usually due to very poor gas (~83
octane) that was supposed to have ethanol added but doesn't. It may or
may not be labeled as having ethanol added even though it might not
have any ethanol. Labeling at the pump is not much of an indication
because mislabeling results in no penalty and the fact is the
retailers often don't know anymore than you do about what is actually
in their tanks. So your claim that you know how much ethanol affects
your mileage is a fantasy.

Alcohol has less energy content than gasoline. Pure and simple. Get
out a CRC and look it up.

FloydR

[Floyd Rogers]

Post by Floyd Rogers
The MN citation is from 2004. The cartalk forum stuff is from 2008.
http://www.ftc.gov/bcp/edu/pubs/consumer/alerts/alt064.shtm
"At the Pump: Use the Octane Level You Need
Your owner's manual recommends the most effective octane level for your car.
For most cars, the recommended gasoline is regular octane. In most cases,
using a higher octane gas than the manufacturer recommends offers no
benefit. Unless your engine is knocking, buying higher octane gasoline is a
waste of money. "
Since most cars are tuned for 87 octane, they won't get better mileage on
91.

So, I see that you also believe that 2004 and 2005 is not recent, and
that authorities sources are not believable.

FloydR

[jim <"sjedgingN0sp"@]

Post by Floyd Rogers
So, I see that you also believe that 2004 and 2005 is not recent, and
that authorities sources are not believable.

This has been the conventional wisdom for ever you act like it is
something they just determined in 2004 and 2005. These same
authorities would have said exactly the same thing in 1964 and 1965.
Laboratories that have done research recently on new cars say
different then those authorities that parrot textbooks written 50
years ago.

-jim


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[doug]

Post by Elmo P. Shagnasty
wow, how uninformed can one person be.

I wonder - just how uninformed are you? The 3.8 supercharged engine uses a
knock sensor to vary engine operation - higher octane permits it to run at
full optimization. Unless you have a foot of pure lead, this results in
increased engine efficiency/fuel economy.

[jim <"sjedgingN0sp"@]

Post by doug

Post by Elmo P. Shagnasty
wow, how uninformed can one person be.

I wonder - just how uninformed are you? The 3.8 supercharged engine uses a
knock sensor to vary engine operation - higher octane permits it to run at
full optimization. Unless you have a foot of pure lead, this results in
increased engine efficiency/fuel economy.

That's right and true of most modern cars. The only question is will
the increased gas mileage offset the increased $/gal. And even if you
have a lead foot you are likely to get better mileage if you drive the
same way on the same route. For some cars that may be the class of
drivers that benefit the most.

-Jim


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[Mike Marlow]

Post by doug

Post by Elmo P. Shagnasty
wow, how uninformed can one person be.

I wonder - just how uninformed are you? The 3.8 supercharged engine uses
a knock sensor to vary engine operation - higher octane permits it to run
at full optimization. Unless you have a foot of pure lead, this results
in increased engine efficiency/fuel economy.

Yeah - I know. But - real world experience... I owned a 3.8L Supercharged
Buick. I saw no significant difference in mileage or performance between 87
octane and high octane. The engine adjusts itself to the gas, and optimizes
for what's in the tank. Granted - that will be somewhat lower for 87 octane
than for high octane, but I never saw enough of a difference to make a
difference. Don't know about the other poster Doug - but I'm informed.
Beyond what the spec sheet says.

[Retired VIP]

On Wed, 30 Jul 2008 18:09:05 -0400, "Mike Marlow"

Post by Mike Marlow

Post by doug

Post by Elmo P. Shagnasty
wow, how uninformed can one person be.

I wonder - just how uninformed are you? The 3.8 supercharged engine uses
a knock sensor to vary engine operation - higher octane permits it to run
at full optimization. Unless you have a foot of pure lead, this results
in increased engine efficiency/fuel economy.

Yeah - I know. But - real world experience... I owned a 3.8L Supercharged
Buick. I saw no significant difference in mileage or performance between 87
octane and high octane. The engine adjusts itself to the gas, and optimizes
for what's in the tank. Granted - that will be somewhat lower for 87 octane
than for high octane, but I never saw enough of a difference to make a
difference. Don't know about the other poster Doug - but I'm informed.
Beyond what the spec sheet says.

Today's cars don't tune themselves for better performance if you put
in higher octane gas than they need. They have a default point of
operation which is usually their most economical operating tune. Only
if the fuel doesn't meet the engine's requirements does the computer
de-tune the engine. It the engine is designed to run on 87 octane
gas, the engine efficiency will be at it's best if you use 87 octane
gas. You can burn 89 or 91 octane gas in a car designed for 87 with
no drop in performance or mileage but there won't be any increase over
what 87 octane provides.

Octane is a measurement of how hard it is to catch the fuel on fire,
not how much heat energy the fuel contains. The heat energy will be
about the same in all grades of gas. If ethanol is used as the octane
booster then 91 octane will have slightly less heat energy since
ethanol contains about 30% less heat energy than gasoline.

The octane requirement of an engine is determined by the engine's
compression ratio, valve timing, ignition timing, fuel/air mixture,
etc. The engine computer can control some of these in all engines but
it can only de-tune to compensate for a fuel that doesn't meet the
engine's requirements.

A supercharged or turbocharged engine runs at an effectively higher
compression ratio under boost than it's spec sheet ratio. Boost
forces more fuel/air mixture into the engine which will raise the
effective compression ratio. So a boosted engine will almost always
require premium fuel.

Jack

[jim <"sjedgingN0sp"@]

Post by Retired VIP
On Wed, 30 Jul 2008 18:09:05 -0400, "Mike Marlow"

Post by Mike Marlow

Post by doug

Post by Elmo P. Shagnasty
wow, how uninformed can one person be.

I wonder - just how uninformed are you? The 3.8 supercharged engine uses
a knock sensor to vary engine operation - higher octane permits it to run
at full optimization. Unless you have a foot of pure lead, this results
in increased engine efficiency/fuel economy.

Yeah - I know. But - real world experience... I owned a 3.8L Supercharged
Buick. I saw no significant difference in mileage or performance between 87
octane and high octane. The engine adjusts itself to the gas, and optimizes
for what's in the tank. Granted - that will be somewhat lower for 87 octane
than for high octane, but I never saw enough of a difference to make a
difference. Don't know about the other poster Doug - but I'm informed.
Beyond what the spec sheet says.

Today's cars don't tune themselves for better performance if you put
in higher octane gas than they need. They have a default point of
operation which is usually their most economical operating tune. Only
if the fuel doesn't meet the engine's requirements does the computer
de-tune the engine. It the engine is designed to run on 87 octane
gas, the engine efficiency will be at it's best if you use 87 octane
gas. You can burn 89 or 91 octane gas in a car designed for 87 with
no drop in performance or mileage but there won't be any increase over
what 87 octane provides.

The problem with that is it is a textbook explanation that is outdated
and completely ignores reality. In order to maximize fuel efficiency
and performance many modern engines are programmed to run right up to
the point where detonation occurs. Ideally you would have a small
amount of detonation every firing of a cylinder. Detonation is not
something that is black and white, it is not on or off it is dynamic
and varies in degree. Modern engines are designed to hold the tune so
that detonation is at a point where it maximizes performance. The
knock sensor is not the only thing to respond to more than the minimum
amount of detonation. The air/fuel trim can also respond due to
disruption of complete combustion when detonation exceeds that point
of maximum efficiency.
That means slight changes in octane do make a difference. Couple that
with the fact that octane is a whole lot more complicated than a
single number on a pump. Add to that that the number on the pump is
not as reliable as you might expect and the reality is that no one can
predict the actual mileage effect of going from one brand to the next
or one octane level to the next within one brand. You can read a book
and have it tell you it won't make a difference but you are only
fooling yourself. People who test this in a controlled manner almost
always find some increase in mileage as octane increases. Often that
increase is too small to pay for the extra cost.
It isn't just the fuel that is an unreliable input to your
comfortable formulas it is the engine itself that is unknown quantity.
Lots of things in the engine also affect detonation and thus how much
the engine retunes to accommodate. Even slight changes in engine
temperature affect detonation. So does slight changes in the intake
air temp as well as atmospheric pressure. When a low pressure system
is passing thru everyone's engine is less likely to detonate. And of
course Air/fuel mixture and EGR mix both raise or lower the tendency
to detonate at any particular moment. And then there are slight
defects like vacuum leaks and dirty injectors and dirty or poorly
gapped spark plugs that all affect the engines tendency to knock.
Carbon accumulation in the combustion chamber can also cause
detonation. And what happens then? Well the engine detunes and that
may cause more carbon accumulation. A tank of premium at that point
could break what might become a slow death spiral.

So you tell me you can read a book and read the mfg's specs and tell
me exactly how my engine will react to tank of premium. I don't think
so.

Post by Retired VIP
Octane is a measurement of how hard it is to catch the fuel on fire,
not how much heat energy the fuel contains.

No it is a rating indicating how much the fuel theoretically has a
tendency to detonate. As a counter example to your claim, hydrogen
catches fire much easier than any gasoline component yet it has an
octane rating much higher than any gasoline component.
It is theoretical limit because there is no way to predict with
certainty how any particular blend of fuels will work in any
particular engine. Testing in an engine is still the method for
determining octane even though today they can determine the exact
molecular composition of the fuel.
If someone really want to know how their particular vehicle responds
to any particular gasoline you have to try it and see. It's true the
vast majority of vehicles will see only diminishing returns for octane
levels above what the manufacture recommends. But how much your engine
varies from the norm can only be determined by doing controlled tests.

Post by Retired VIP
The heat energy will be
about the same in all grades of gas. If ethanol is used as the octane
booster then 91 octane will have slightly less heat energy since
ethanol contains about 30% less heat energy than gasoline.

Even when no ethanol is present on average higher octane fuel contains
less energy than low octane. It is just in the nature of the gasoline
fractions that the ones that contribute the most to detonation (for
example heptane) also contain the most energy. But the energy content
is for all practical purposes irrelevant. If energy content was all
that was important for fuel economy then you would burn diesel in your
gas engine.

-jim

Post by Retired VIP
The octane requirement of an engine is determined by the engine's
compression ratio, valve timing, ignition timing, fuel/air mixture,
etc. The engine computer can control some of these in all engines but
it can only de-tune to compensate for a fuel that doesn't meet the
engine's requirements.
A supercharged or turbocharged engine runs at an effectively higher
compression ratio under boost than it's spec sheet ratio. Boost
forces more fuel/air mixture into the engine which will raise the
effective compression ratio. So a boosted engine will almost always
require premium fuel.
Jack

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"jim" <"sjedgingN0sp"@***@mwt.net> wrote in message news:***@isp.n...

....

Post by jim <"sjedgingN0sp"@

Post by Retired VIP
Octane is a measurement of how hard it is to catch the fuel on fire,
not how much heat energy the fuel contains.

No it is a rating indicating how much the fuel theoretically has a
tendency to detonate. As a counter example to your claim, hydrogen
catches fire much easier than any gasoline component yet it has an
octane rating much higher than any gasoline component.

Actually hydrogen is not a good example to use. It has a high RON rating
(research method) and a low MON rating (motor method). In an Otto Cycle
engine hydrogen tends to pre-ignite and therefore acts like a low octane
gasoline.

Post by jim <"sjedgingN0sp"@
It is theoretical limit because there is no way to predict with
certainty how any particular blend of fuels will work in any
particular engine. Testing in an engine is still the method for
determining octane even though today they can determine the exact
molecular composition of the fuel.
If someone really want to know how their particular vehicle responds
to any particular gasoline you have to try it and see. It's true the
vast majority of vehicles will see only diminishing returns for octane
levels above what the manufacture recommends. But how much your engine
varies from the norm can only be determined by doing controlled tests.

And as I said before - how you drive will have an effect as well. Someone
who almost never drives at WOT is likely to see less of a difference than
someone who routinely drives hard.

Post by jim <"sjedgingN0sp"@

Post by Retired VIP
The heat energy will be
about the same in all grades of gas. If ethanol is used as the octane
booster then 91 octane will have slightly less heat energy since
ethanol contains about 30% less heat energy than gasoline.

Even when no ethanol is present on average higher octane fuel contains
less energy than low octane. It is just in the nature of the gasoline
fractions that the ones that contribute the most to detonation (for
example heptane) also contain the most energy. But the energy content
is for all practical purposes irrelevant. If energy content was all
that was important for fuel economy then you would burn diesel in your
gas engine.

I was taught that higher octane gasoline had a lower energy content than
regular when I was in college - 30+ years ago. However since then I have
seen many credible sources saying this is not true.

From http://www.api.org/aboutoilgas/gasoline/gasoline-octane.cfm :

"Gasoline with a higher heating value (energy content) provides better fuel
economy. Traditionally, premium gasoline has had a slightly higher heating
value than regular, and, thus, provides slightly better fuel economy, but it
is difficult to detect in normal driving. There can be even larger
differences in heating value between batches of gasoline from the same
refinery, between summer and winter volatility classes, or between brands of
gasoline from different refineries because of compositional differences. The
differences are small and there is no practical way for the consumer to
identify gasoline with a higher-than-average heating value."

Other interesting references:

http://www.sciam.com/article.cfm?id=fact-or-fiction-premium-g
http://www.consumerenergycenter.org/transportation/consumer_tips/regular_vs_premium.html
http://ask.cars.com/2007/07/premium-gasolin.html
http://www.cartalk.com/content/features/premium/myths.html
http://www.caranddriver.com/reviews/hot_lists/high_performance/features_classic_cars/regular_or_premium_feature+t-test_results+page-2.html
or http://tinyurl.com/6pwz27

It is my opinion that if your car was designed to run on regular, running
premium is a waste of money. Although the engine may be able to adjust some
parameters to increase performance and fuel economy, the changes will be
minor. On the other hand, if your car was designed to run on premium
(because of turbocharging/supercharging, a higher compression ratio, or
other inherent design factors) then running regular may drastically effect
your performance and fuel economy even if the PCM can adjust parameters to
protect the engine from excessive pre-ignition.

Regards,

Ed White

[Built_Well]

Post by C. E. White
http://www.cartalk.com/content/features/premium/myths.html

========

Ed, that Car Talk page is a great link. Thanks for providing it.
I'm copying part of it into the newsgroup for permanent
archiving.

CarTalk.com passage:

It's true that premium gas does contain special or extra detergents,
but in our opinion they're of no additional benefit.

Our advice is to ignore any sales pitch about the super-special
detergents that come in the premium-grade fuel.

These days, all of the gasoline from the major gas companies contain
more than enough detergents to keep your engine clean. Period.

The only reason you might have a use for the extra detergents in
premium,
is if you have a noticeably dirty engine, and need to scrub carbon and
other
crud off engine components. (And, if you're doing that, we'd instead
suggest
that you toss in one of the many fine engine additives.)

You said "major gas companies." Is there a difference in the gas
between
the big names, and the El-Cheapo gasoline at my local Costco or
Stupey-Mart?

There is. A number of years ago, some of the major auto manufacturers
were ticked off with the deposits from gas that met EPA detergent
standards. In other words, they were afraid they'd take the heat for
problems, when their customer's engines clogged up from the twigs
and dirt that was getting deposited on their fine handiwork.

So, they set their own guidelines, which they call "Tier 2." All of
the gas
from the major gas companies meets the Tier 2 standards. The gas at
your local Quickie Mart probably does not. The difference? In some
tests, after about 10,000 miles, there was a minor amount of crud
built
up on engine components that ran exclusively on Quickie-Mart gas.
Do we think this is an issue? Not really. But, would we advise
running
your car for 100,000 miles only on Quickie-Mart gas? Not if you're
concerned about the longevity of your vehicle. We recommend switching
back and forth between Tier 1 and Tier 2 — maybe every other
tank full — to keep your engine running clean.

[C. E. White]

Post by Retired VIP
On Wed, 30 Jul 2008 18:09:05 -0400, "Mike Marlow"

Post by Mike Marlow

Post by doug

Post by Elmo P. Shagnasty
wow, how uninformed can one person be.

I wonder - just how uninformed are you? The 3.8 supercharged engine uses
a knock sensor to vary engine operation - higher octane permits it to run
at full optimization. Unless you have a foot of pure lead, this results
in increased engine efficiency/fuel economy.

Yeah - I know. But - real world experience... I owned a 3.8L Supercharged
Buick. I saw no significant difference in mileage or performance between 87
octane and high octane. The engine adjusts itself to the gas, and optimizes
for what's in the tank. Granted - that will be somewhat lower for 87 octane
than for high octane, but I never saw enough of a difference to make a
difference. Don't know about the other poster Doug - but I'm informed.
Beyond what the spec sheet says.

Today's cars don't tune themselves for better performance if you put
in higher octane gas than they need. They have a default point of
operation which is usually their most economical operating tune. Only
if the fuel doesn't meet the engine's requirements does the computer
de-tune the engine. It the engine is designed to run on 87 octane
gas, the engine efficiency will be at it's best if you use 87 octane
gas. You can burn 89 or 91 octane gas in a car designed for 87 with
no drop in performance or mileage but there won't be any increase over
what 87 octane provides.
Octane is a measurement of how hard it is to catch the fuel on fire,
not how much heat energy the fuel contains. The heat energy will be
about the same in all grades of gas. If ethanol is used as the octane
booster then 91 octane will have slightly less heat energy since
ethanol contains about 30% less heat energy than gasoline.
The octane requirement of an engine is determined by the engine's
compression ratio, valve timing, ignition timing, fuel/air mixture,
etc. The engine computer can control some of these in all engines but
it can only de-tune to compensate for a fuel that doesn't meet the
engine's requirements.
A supercharged or turbocharged engine runs at an effectively higher
compression ratio under boost than it's spec sheet ratio. Boost
forces more fuel/air mixture into the engine which will raise the
effective compression ratio. So a boosted engine will almost always
require premium fuel.
Jack

In the past, Ford claimed that the 5.4L V-8, which was intended to run on
regular fuel would have slightly higher fuel economy and slightly more power
if premium fuel was used. Their claim was a maximum improvement of around 3%
increase in fuel economy and maybe an extra 5 horsepower. I don't think must
people could reliably detect either change. I owned 2 Expeditions with the
5.4L V-8 and tried both regular and premium for extended periods and I never
could see any difference in mileage between the two. And there is no way I'd
ever be able to tell the difference between 265 hp and 270 hp just by
driving. I have also compared regular and premium in my Nissan Frontier
(4.0L V-6). Nissan says the truck is designed to run on regular fuel, but
that for maximum economy and performance premium should be used. The first
time I ran premium, the mileage records indicated a significant increase in
fuel economy, However, when I switched back to regular, the mileage stayed
the same. Since then I have tried premium for other extended periods, and
the mileage has not shown any improvement compared to regular.

One factor you guys don't seem to be considering is the effect of the
driver. Knock sensors adjust the engine parameters based on detecting knock.
The PCM doesn't know the type of fuel, only how the engine is reacting as
indicated by the presence of knock. What do you suppose happens in the case
of a driver who is very gentle and never provokes the engine to knock even
when running on regular? I am guessing it will adjust the engine parameters
in the same manner as if the engine was running premium. I suspect this
might be why some people claim significant difference when running premium,
while other (like me) see no difference.

Chevron used to have a really good set of web pages discussing gasoline.
Unfortunately they have replaced those with some advertising inspired
drivel. As I recall, the old Chevron pages addressed the question of energy
content of premium and regular. They claimed premium contained around 3%
more energy than regular on average, but that the energy content of gasoline
in general varied by around this same amount, so in some cases a particular
batch of premium might have less energy than a particular batch of regular.

At least in North Carolina, gasoline samples are routinely checked to verify
the octane.

The gasoline FAQ http://www.faqs.org/faqs/autos/gasoline-faq/part1/ is an
interesting, if not always accurate source of information on gasoline.

Regards,

Ed White

[jim <"sjedgingN0sp"@]

Post by C. E. White

Post by Retired VIP
On Wed, 30 Jul 2008 18:09:05 -0400, "Mike Marlow"

Post by Mike Marlow

Post by doug

Post by Elmo P. Shagnasty
wow, how uninformed can one person be.

I wonder - just how uninformed are you? The 3.8 supercharged engine uses
a knock sensor to vary engine operation - higher octane permits it to run
at full optimization. Unless you have a foot of pure lead, this results
in increased engine efficiency/fuel economy.

Yeah - I know. But - real world experience... I owned a 3.8L Supercharged
Buick. I saw no significant difference in mileage or performance between 87
octane and high octane. The engine adjusts itself to the gas, and optimizes
for what's in the tank. Granted - that will be somewhat lower for 87 octane
than for high octane, but I never saw enough of a difference to make a
difference. Don't know about the other poster Doug - but I'm informed.
Beyond what the spec sheet says.

Today's cars don't tune themselves for better performance if you put
in higher octane gas than they need. They have a default point of
operation which is usually their most economical operating tune. Only
if the fuel doesn't meet the engine's requirements does the computer
de-tune the engine. It the engine is designed to run on 87 octane
gas, the engine efficiency will be at it's best if you use 87 octane
gas. You can burn 89 or 91 octane gas in a car designed for 87 with
no drop in performance or mileage but there won't be any increase over
what 87 octane provides.
Octane is a measurement of how hard it is to catch the fuel on fire,
not how much heat energy the fuel contains. The heat energy will be
about the same in all grades of gas. If ethanol is used as the octane
booster then 91 octane will have slightly less heat energy since
ethanol contains about 30% less heat energy than gasoline.
The octane requirement of an engine is determined by the engine's
compression ratio, valve timing, ignition timing, fuel/air mixture,
etc. The engine computer can control some of these in all engines but
it can only de-tune to compensate for a fuel that doesn't meet the
engine's requirements.
A supercharged or turbocharged engine runs at an effectively higher
compression ratio under boost than it's spec sheet ratio. Boost
forces more fuel/air mixture into the engine which will raise the
effective compression ratio. So a boosted engine will almost always
require premium fuel.
Jack

In the past, Ford claimed that the 5.4L V-8, which was intended to run on
regular fuel would have slightly higher fuel economy and slightly more power
if premium fuel was used. Their claim was a maximum improvement of around 3%
increase in fuel economy and maybe an extra 5 horsepower. I don't think must
people could reliably detect either change. I owned 2 Expeditions with the
5.4L V-8 and tried both regular and premium for extended periods and I never
could see any difference in mileage between the two. And there is no way I'd
ever be able to tell the difference between 265 hp and 270 hp just by
driving. I have also compared regular and premium in my Nissan Frontier
(4.0L V-6). Nissan says the truck is designed to run on regular fuel, but
that for maximum economy and performance premium should be used. The first
time I ran premium, the mileage records indicated a significant increase in
fuel economy, However, when I switched back to regular, the mileage stayed
the same. Since then I have tried premium for other extended periods, and
the mileage has not shown any improvement compared to regular.
One factor you guys don't seem to be considering is the effect of the
driver.

That is right. Drivers tend to respond differently to how the car
behaves. Some drivers respond to less power by stepping down on the
gas pedal. Other drivers do just the opposite - when they sense a flat
spot in the acceleration curve as they step on the gas pedal they back
off and stay just below that point. Other drivers are pretty much
oblivious to acceleration and respond to the cars speed.

Post by C. E. White
Knock sensors adjust the engine parameters based on detecting knock.
The PCM doesn't know the type of fuel, only how the engine is reacting as
indicated by the presence of knock. What do you suppose happens in the case
of a driver who is very gentle and never provokes the engine to knock even
when running on regular?

Knock is not something that is turned on or off like a light switch.
In a perfect world you would want an engine designed to knock to some
extent at all times (except when decelerating) That would maximize the
amount of energy from each load of fuel and air. That means delivering
the maximum amount of pressure as early as possible from a given
amount of fuel. But there is a limit and going beyond that point does
increase the pressure pulse and that seems like a good thing for fuel
economy but too great a pressure spike (knock is just a pressure
spike)) also destabilizes combustion so going beyond this ideal point
reduces fuel economy. No matter what amount of throttle the driver is
trying to deliver to the wheels you still have this balance point
where any additional leaning of the mixture or advancing of the timing
will result in too much knock (i.e. too big a pressure spike) and not
enough will waste fuel. When the engine is under light load for
maximum fuel efficiency the timing advances and fuel mixtures become
leaner this brings the charge right up to that ideal knock point. But
where that point is can't be predicted - it is arrived at by content
feedback. And there are many things that determine the knock point
besides fuel octane rating. Engine temperature, inlet air pressure and
temperature, EGR volume, compression ratio, spark plug gap and
secondary voltage are some of the things that effect the knock point
in any engine.

In automotive engineering terms what you ask about is called "octane
sensitivity". And one of the problems with the widespread use of
ethanol today is that ethanol is an extremely octane sensitive fuel.
Ethanol used under light loads has an octane capability that is really
no better than mid grade gasoline. But under heavy loads its octane
rating is much much higher than premium fuel. That means adding
ethanol as an octane booster isn't going to help the fuel economy of
the guy "who is very gentle" compared to someone who drives more
aggressively and fast.


There are limits to how much engines can respond to more octane and
when you reach the limit and go beyond usually means less mpg. But
given that most cars today seem to be deigned beyond the limit of base
87 octane fuel and most labeled 87 octane fuel is actually slightly
lower than that labeled 87 octane, it is a fairly safe bet that most
newer cars will get some more miles from higher octane. But if it
isn't more than %5 better then it isn't really going to be worth it.
Most of the time the differences are going to be small and hard to
detect unless you are very meticulous about keeping records and
driving in exactly the same way.

-jim

Post by C. E. White
I am guessing it will adjust the engine parameters
in the same manner as if the engine was running premium. I suspect this
might be why some people claim significant difference when running premium,
while other (like me) see no difference.
Chevron used to have a really good set of web pages discussing gasoline.
Unfortunately they have replaced those with some advertising inspired
drivel. As I recall, the old Chevron pages addressed the question of energy
content of premium and regular. They claimed premium contained around 3%
more energy than regular on average, but that the energy content of gasoline
in general varied by around this same amount, so in some cases a particular
batch of premium might have less energy than a particular batch of regular.
At least in North Carolina, gasoline samples are routinely checked to verify
the octane.
The gasoline FAQ http://www.faqs.org/faqs/autos/gasoline-faq/part1/ is an
interesting, if not always accurate source of information on gasoline.
Regards,
Ed White

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[Floyd Rogers]

Post by C. E. White
In the past, Ford claimed that the 5.4L V-8, which was intended to run on
regular fuel would have slightly higher fuel economy and slightly more
power if premium fuel was used. Their claim was a maximum improvement of
around 3% increase in fuel economy and maybe an extra 5 horsepower. I
don't think must people could reliably detect either change.

Yeah, I agree. There's a very nice article on Dinan's website about
dynonometer
testing that has a section on 93 vs. 91 octane fuels. They measured an 11
HP
(IIRC - can't get to their website right now) on an E46 M3 - but that's only
3%.
Important on the racetrack, but inconsequential in everyday driving, as 343
hp
is more than sufficient.

Post by C. E. White
One factor you guys don't seem to be considering is the effect of the
driver. Knock sensors adjust the engine parameters based on detecting
knock. The PCM doesn't know the type of fuel, only how the engine is
reacting as indicated by the presence of knock. What do you suppose
happens in the case of a driver who is very gentle and never provokes the
engine to knock even when running on regular? I am guessing it will adjust
the engine parameters in the same manner as if the engine was running
premium. I suspect this might be why some people claim significant
difference when running premium, while other (like me) see no difference.

I completely agree. Although it's likely that, in very well-controlled
experiments premium fuel may give someone with an engine designed
for high-octane fuels a little more mpg, in everyday driving you're not
likely to notice any differences. As I've mentioned in other sub-threads,
the effect on blends, especially of ethanol, is likely to be more
noticeable.

The faq gives some nice info on how closely experiments must be
controlled, particularly temperature. Also, I hadn't really considered the
fact that the high operating temperatures that BMW's are set up for also
increase the need to run them on premium, for max performance.

It's too bad that Jim won't read and believe the faq.

FloydR

[Hachiroku ハチロク]

Post by c***@hotmail.com

You can buy on price, or you can buy on value.  If you buy on price,
you'll probably spend more per mile to fuel your car.

I think you hit the nail on the head, Elmo, at least on certain types
of cars.
I've had my 98 Pontiac Grand Prix GTP for a little over ten years now,
and follow the gas mileage carefully. Using 92 octane, I will get a
full mile per gallon better than using mid-grade. Using 87 octane will
cost me 3-4 mpg, so it costs me a LOT more by using the cheaper
gasoline. The difference in acceleration is very noticeable as well.

I kept a book in the glove for a '95 Tercel I owned. I started with 89
Octane, and changed to 93 Octane. There was a difference, and I figured
over the period I owned the car I paid $225 LESS for Premium.

[Elmo P. Shagnasty]

Post by Fat Moe
I use regular in them,
top tier regular if it's there but I don't worry all that much about
it. The EPA has standards for fuel which must be met and deposit
problems are addressed by them.

That's the issue: no, deposit problems are NOT addressed with govt
standard level additives.

[Fat Moe]

Post by Elmo P. Shagnasty

Post by Fat Moe
I use regular in them,
top tier regular if it's there but I don't worry all that much about
it. The EPA has standards for fuel which must be met and deposit
problems are addressed by them.

That's the issue: no, deposit problems are NOT addressed with govt
standard level additives.

Then what is this all about ?
http://www.epa.gov/EPA-AIR/1996/July/Day-05/pr-23484.txt.html

[h***@h-gee.co.uk]

Post by Fat Moe

Post by Elmo P. Shagnasty

Post by Fat Moe
I use regular in them,
top tier regular if it's there but I don't worry all that much about
it. The EPA has standards for fuel which must be met and deposit
problems are addressed by them.

That's the issue: no, deposit problems are NOT addressed with govt
standard level additives.

Then what is this all about ?
http://www.epa.gov/EPA-AIR/1996/July/Day-05/pr-23484.txt.html

Agreed - most gov' agencies lay down standards but they are NEVER top tier as
you put it.

Take mobile/cell phones for one - basic standards exist - to make and receive
phone calls. Some makes/models do it better than others and some have bells and
whistles like movie cameras and 10Meg Pix still cameras and Internet access etc
and probably in the not too distant future a ray gun or two and a tea maker and
some have quad band access so I can use mine over there in the USA and Japan as
well as Euroland and the UK.
--
Sir Hugh of Bognor

The difference between men and boys is the price of their toys.

Intelligence is not knowing the answer but knowing where and how to find it!

Hugh Gundersen
***@h-gee.co.uk
Bognor Regis, W.Sussex, England, UK

[Fat Moe]

Post by h***@h-gee.co.uk

Post by Fat Moe

Post by Elmo P. Shagnasty

Post by Fat Moe
I use regular in them,
top tier regular if it's there but I don't worry all that much about
it. The EPA has standards for fuel which must be met and deposit
problems are addressed by them.

That's the issue: no, deposit problems are NOT addressed with govt
standard level additives.

Then what is this all about ?
http://www.epa.gov/EPA-AIR/1996/July/Day-05/pr-23484.txt.html

Agreed - most gov' agencies lay down standards but they are NEVER top tier as
you put it.
Take mobile/cell phones for one - basic standards exist - to make and receive
phone calls. Some makes/models do it better than others and some have bells and
whistles like movie cameras and 10Meg Pix still cameras and Internet access etc
and probably in the not too distant future a ray gun or two and a tea maker and
some have quad band access so I can use mine over there in the USA and Japan as
well as Euroland and the UK.

If I buy Nike shoes can I run and jump faster?

[Elmo P. Shagnasty]

Post by Fat Moe

Post by Elmo P. Shagnasty

Post by Fat Moe
I use regular in them,
top tier regular if it's there but I don't worry all that much about
it. The EPA has standards for fuel which must be met and deposit
problems are addressed by them.

That's the issue: no, deposit problems are NOT addressed with govt
standard level additives.

Then what is this all about ?
http://www.epa.gov/EPA-AIR/1996/July/Day-05/pr-23484.txt.html

They set a standard. So what?

The standard was set on behalf of gas company lobbyists, whose handlers
didn't want to increase the cost of doing business.

The standard is a minimum. That doesn't mean it's effective.

[C. E. White]

Post by Elmo P. Shagnasty

Post by Fat Moe
I use regular in them,
top tier regular if it's there but I don't worry all that much about
it. The EPA has standards for fuel which must be met and deposit
problems are addressed by them.

That's the issue: no, deposit problems are NOT addressed with govt
standard level additives.

Opinion or fact? If fact, please cite a reference.

I know GM and others recommend top tier gasoline. Ford recommends BP.
The US EPA claims that all US gasoline contains the minimum about of a
fuel system cleaner to be effective (see
http://www.epa.gov/EPA-AIR/1996/July/Day-05/pr-23484.txt.html ). There
is some question about what is being controlled. Apparently the EPA is
only concerned with fuel injector and valve deposits and not with
combustion chamber deposits. The top tier gasoline standard does
address combustion chamber deposits but not in the manner you might
think.....see http://www.toptiergas.com/deposit_control.html : "The
base fuel from 1.3.1.2 treated with additive at the concentration
meeting the standard found in 1.3.1.3 shall not result in more than
140% of the average CCD weight for the base fuel without additive." So
for top tier gasoline you are allowed to have greater combustion
chamber deposits than is the case for the base fuels...very strange.

I believe you are incorrect when you say "deposit problems are NOT
addressed with govt standard level additives." I suggest you read the
EPA reference cited above. It has a lot more detail than I am willing
to quote. A couple of key points - 1) not all gasoline is the same
when it comes to deposit forming characteristics, 2) the required
properties of gasoline vary for different regions (different blends
are required in different areas), 3) the EPA has established national
limits for deposit fighting additives, 4) the minimum level specified
by the EPA is based on an "average" gasoline, thus in some areas the
amount of fuel system cleaners in the gasoline may far exceed the need
while for other feedstocks it may actually be insufficient (but the
theory is no one car is going to continually get gasoline with too low
a level of fuel system cleaners), 5) the use of ethanol may reduce the
effectiveness of some fuel system cleaners. The following statement is
from the EPA Rule:

" (i) Detergent additives for the control of port fuel injector
deposits (PFID) and/or intake valve deposits (IVD) in gasoline engines
may not be transferred or sold for use in compliance with this subpart
unless such additives have been certified according to the
requirements of this section.
(ii) Except as provided in Sec. 80.169(c)(8), PFID and IVD control
additives may not be added to gasoline or post-refinery component PRC)
for compliance with this subpart unless such additives have been
certified according to the requirements of this section.
(iii) Gasoline may not be sold or transferred to a party who sells
or transfers gasoline to the ultimate consumer unless such gasoline
contains detergent additives which have been certified according to
the requirements of this section.

" (2) Beginning August 1, 1997, all gasoline sold or transferred to
the ultimate consumer must contain detergent additive(s) which have
been certified, according to the requirements of this section, to be
effective for the control of PFID and IVD in gasoline engines."

I don't see where the "Top Tier" gasoline program requires anything
more stringent than this when it comes to "control of PFID and IVD in
gasoline engines." They do address combustion chamber deposits (by
allowing them to be 140% of the level for untreated fuel?????) and
valve sticking. I suppose Top Tier gasoline may have some advantage,
but it almost seems to me that it is more of a marketing ploy than a
real performance standard.

Years ago (I am talking about the early 1990's) it was common for
branded gasolines to advertise that their premium grades included
higher levels of fuel system cleaners than their regular grades. I
also know that prior to the implementation of the EPA requirements
that unbranded gas often did not contain fuel system cleaners. But the
situation today is not so clear. By rule all gasoline must include an
effective level of fuel system cleaners. As I read the EPA
information, it is possible that some gasoline that are more likely to
create deposits than others might not have as high a level of fuel
system cleaner as necessary to prevent deposits, but that it is not
likely that any one vehicle would consistently receive this type of
gasoline. I would hope that all premium gasoline is not the type that
is likely to be the deposit forming variety, and therefore the EPA
mandated level of fuel system cleaners is more than sufficient for
premium grades. So it seems that there is no reason for refiners to
add extra fuel system cleaners to premium gasoline. And in fact, I
rarely see it claimed that this is the case these days. Furthermore,
based on my reading of the Top Tier Gasoline standards, it appears
that fuel system cleaners might actually increase the level of
combustion chamber deposits (why else would the TT standard allowed
increased levels of CCDs?). So I think having to high a level of fuel
system cleaners in gasoline might actually be a bad thing.

A few opinions:

- Unleaded gasoline is a commodity. Just because the station says
Shell or BP on the pumps does not imply that the gasoline was refined
at a Shell or BP refinery. I hope that having Shell or BP or whatever
on the pumps guarantees that the gasoline being sold meets the brand's
quality standards, contains the brand's standard additive package, and
is of consistent quality.

- Top Tier Gasoline may in fact meet additional standards, but I
suspect it is more of a marketing ploy than anything else. At most, it
is a way for car manufacturers to encourage car owners to stay away
from crappy gas and a way for refiners to differentiate their products
so they can charge a few extra pennies. I am not going out of my way
to look for Top Tier gasoline.

- Unless your vehicle requires premium you are wasting your money if
you buy premium. I know many vehicles with knock systems can adjust
the engine parameters to improve performance and increase mileage when
premium gas is used, but you are never going to increase the mileage
enough to recoup the higher cost of the gasoline.

- Mid-grade fuel is a total rip off.

- At least where I live, there appears to be no downside from using
unbranded gasoline, or gasoline from second tier suppliers. Although I
occasionally buy gas at a BP or Shell station, for the most part I use
Costco, Wilco, Raceway, and Pantry gasoline. I keep a log book and I
see no deterioration in fuel economy. I can detect no decrease in
performance. I have not had the heads off,or looked at the valves to
verify that there are (or are not) deposit problem, but why would I do
something like that? My Sister recently sold her 1997 Civic with 140k
miles. The car was a rolling piece of junk, but the engine ran fine.
She never bought anything but the cheapest gas she could find. I
suppose in other areas there may be gas which is more likely to form
deposits, and therefore cheap gas may cause problems, but at least in
my area (central / eastern NC) that does not appear to be the case.

Ed

[Elmo P. Shagnasty]

Post by C. E. White
I know GM and others recommend top tier gasoline. Ford recommends BP.

That's hilarious, because the local lawnmower shop specifies NOT to use
BP under any circumstances.

This place has been around for 50 years, and they've said that for as
long as I can remember.

[C. E. White]

Post by Elmo P. Shagnasty

Post by C. E. White
I know GM and others recommend top tier gasoline. Ford recommends BP.

That's hilarious, because the local lawnmower shop specifies NOT to use
BP under any circumstances.
This place has been around for 50 years, and they've said that for as
long as I can remember.

But why did they say not to use BP? And which "BP" didn't they like? I've
been around gas stations for more than 50 years. My Cousin ran a Sinclair
station when I was a little kid. I hung around getting in the way. Sometime
in the 60's BP bought out Sinclair (at least in the east) and the station
remained a BP station for years - but the gasoline came by the same old
trucks from the same old terminal and was actually refined in Yorktown,Va at
an Amoco refinery. Later BP took over Standard of Indiana (aka Standard,
Boron, Amoco, American, etc. depending on the market). All of the Amoco
station around here are now BP stations, but they say they sell Amoco
gasoline. They also have a lot of advertising material that claims their
gasoline (premium only???) is higher quality and contains less contaminates.
I suspect that there is not a lot of difference between any of the major
brands (or the no name stuff for that matter). I suspect your friendly
lawnmower shop is just full of it. At the best I suspect they are basing
their recommendation on gasoline from decades ago before the EPA got into
the business of regulating gasoline.

Ed

[Elmo P. Shagnasty]

Post by C. E. White

Post by Elmo P. Shagnasty
This place has been around for 50 years, and they've said that for as
long as I can remember.

But why did they say not to use BP?

Gunks up the engine. Sure, a car will run--but after a couple of weeks,
a lawnmower won't.

They were saying it long ago, in the Sohio days.

[[e-mail]]

Post by C. E. White

Post by Elmo P. Shagnasty

Post by C. E. White
I know GM and others recommend top tier gasoline. Ford recommends BP.

That's hilarious, because the local lawnmower shop specifies NOT to use
BP under any circumstances.
This place has been around for 50 years, and they've said that for as
long as I can remember.

But why did they say not to use BP? And which "BP" didn't they like?

I read somewhere that BP is not a good gas.

[j***@hotmail.com]

The formerly named British Petroleum operates only Amoco and Arco in
the US. Not the top names or on the Tier 1 list. So I guess your shop
is probably right.

However, BP does have excellent lubrication products like Castrol oils
and the likes of GT Low Moisture Activity brake fluids. Maybe their
European gas is Tier 1 equivalent? Don't know.

Post by Elmo P. Shagnasty
That's hilarious, because the local lawnmower shop specifies NOT to use
BP under any circumstances.
This place has been around for 50 years, and they've said that for as
long as I can remember.

[Elmo P. Shagnasty]

In article

Post by j***@hotmail.com
The formerly named British Petroleum operates only Amoco and Arco in
the US.

Really?

Then who operates that BP station a mile from my house? And all the
others around town?

[h***@h-gee.co.uk]

Post by Fat Moe

Post by h***@h-gee.co.uk
On Mon, 28 Jul 2008 13:02:09 -0700 (PDT), Built_Well
Actually one of our car mags here in the UK have just run an article on BP
hi-grade gas & Diesel.
They state that the claims for extra mileage is true but the most convincing for
me at least is the test using an Audi V8 adapted to run one bank on regular
gas/petrol and the other bank on BP Ultimate.
They fitted cameras to the inside of the combustion chambers and the regular
fuel side is a shitty as hell and the BP Ultimate side is like a new stainless
steel sink with no deposits and sparkling clean.
You might see pics on the web "Car Mechanics" or "Kelsey Publishing"
try - http://www.kelsey.co.uk
Hugh

Post by Built_Well
Usually I get 24 miles to the gallon for stop-and-go city
driving with the '06 Camry LE, but this last tankful I got
28 city. I really babied the accelerator pedal this time
and, of course, have plenty of air in the tires. I had
Shell V-Power premium in the tank this time (for its
exceptional detergent levels), but usually I just put in
a regular grade.
I had Hy-Vee Grocery Store premium in there two tankfuls
back, and thought the car was idling kinda rough sometimes
while stopped, so I thought some Shell V-Power was in
order to help clean out any minute amounts of potential
gunk I might have gotten from the Hy-Vee gas.
When I asked him, the Hy-Vee manager said his gas met
the Top Tier standard, but Hy-Vee is not on the list
of Top Tier stations at toptiergas.com, so I doubt
Hy-Vee is Top Tier.
On Hy-Vee, the car once idled at only 600 rpm; I've never
seen it idle so low. Usually 650 to 700 is the lowest it'll
idle at. It could have been a coincidence that the one 600
idle happened under Hy-Vee.
"TOP TIER Gasoline is a new class of gasoline with enhanced
detergency. It meets new, voluntary deposit control standards
developed by four automotive companies - BMW, General Motors,
Honda and Toyota - that exceed the detergent requirements
imposed by the EPA.
"TOP TIER Gasoline keeps engine parts cleaner by reducing
fuel-related deposits, resulting in better performance.
A lower level of detergent may cause a buildup of deposits on
critical engine parts. These deposits can cause stalling,
rough idling, lowered acceleration and other unnecessary
problems in your vehicle--and your life.
* Improves fuel efficiency
* Prevents driving upsets (rough idle, hesitation, stalling
and surge)
* Improves acceleration
* Provides more power
* Reduces emissions
* Cleans dirty engines and keeps new engines clean
MFA Oil Company is proud to join industry leaders by requiring
TOP TIER Gasoline with higher levels of detergent in all grades
and every gallon of gasoline at Break Time Convenience Stores.
Link: http://www.mfaoil.com/index.cfm?show=10&mid=14&pid=4

It all depends on how you look at it. Unless you are racing or
pulling a heavy load up a hill it won't matter what the octane rating
is. Top tier refers to the additives that prevent build up of deposits,
especially on the intake valves. As far as getting extra mileage with
higher octane? I don't buy it, either the argument or the product. A
friend of mine would always by premium fuel, it ranged from 15 to 20
cents more per gallon. I suggested he try regular instead, but it
wasn't until we did the math that he tried it.
It went something like 300K miles divided by 25 miles/gal = 12K gal
times 18 cents = 2160 dollars. To me it's all about what it costs to
get a mile down the road, total expenses. Fuel, tires,insurance
repairs, maintenance. You can drive a Caddie or Lexus and it's going
to cost you more per mile, you can go to the other extreme and drive a
used tin can and get down the road pretty cheap. I've found Honda
Accords and Toyota Camerys to be a pretty good all around cars,
comfortable enough, right size enough, economical enough to get me that
mile down the road without breaking the bank. I use regular in them,
top tier regular if it's there but I don't worry all that much about
it. The EPA has standards for fuel which must be met and deposit
problems are addressed by them. I stay away from ethanol. The only
preignition or knocking I've encountered in a long time are with a
couple of lawnmowers and a motorcycle.
Quit kidding yourself, Do the math and get yourself some free money.

Actually the maths work better here in the UK than there in the US as our gas is
3 x the price of your gas.
--
Sir Hugh of Bognor

The difference between men and boys is the price of their toys.

Intelligence is not knowing the answer but knowing where and how to find it!

Hugh Gundersen
***@h-gee.co.uk
Bognor Regis, W.Sussex, England, UK

[Retired VIP]

Post by h***@h-gee.co.uk
On Mon, 28 Jul 2008 13:02:09 -0700 (PDT), Built_Well
Actually one of our car mags here in the UK have just run an article on BP
hi-grade gas & Diesel.
They state that the claims for extra mileage is true but the most convincing for
me at least is the test using an Audi V8 adapted to run one bank on regular
gas/petrol and the other bank on BP Ultimate.
They fitted cameras to the inside of the combustion chambers and the regular
fuel side is a shitty as hell and the BP Ultimate side is like a new stainless
steel sink with no deposits and sparkling clean.

Don't you guys have 'truth in advertising' laws in the UK?

How did they fit a camera inside the combustion chamber? Do you have
any idea of the conditions, both heat and pressure, inside the
combustion chamber of an operating engine? Do you actually believe
this claim?

Jack

[Elmo P. Shagnasty]

Post by Retired VIP

Post by h***@h-gee.co.uk
They fitted cameras to the inside of the combustion chambers and the regular
fuel side is a shitty as hell and the BP Ultimate side is like a new stainless
steel sink with no deposits and sparkling clean.

Don't you guys have 'truth in advertising' laws in the UK?
How did they fit a camera inside the combustion chamber? Do you have
any idea of the conditions, both heat and pressure, inside the
combustion chamber of an operating engine? Do you actually believe
this claim?

Read more carefully, old man.

They took pictures of the combustion chambers, sure. With the engine
off.

Go back and re-read what he wrote. YOU put words into his mouth when
you ASSumed "camera inside with engine running".

[Retired VIP]

On Tue, 29 Jul 2008 12:58:19 -0400, "Elmo P. Shagnasty"

Post by Elmo P. Shagnasty

Post by Retired VIP

Post by h***@h-gee.co.uk
They fitted cameras to the inside of the combustion chambers and the regular
fuel side is a shitty as hell and the BP Ultimate side is like a new stainless
steel sink with no deposits and sparkling clean.

Don't you guys have 'truth in advertising' laws in the UK?
How did they fit a camera inside the combustion chamber? Do you have
any idea of the conditions, both heat and pressure, inside the
combustion chamber of an operating engine? Do you actually believe
this claim?

Read more carefully, old man.
They took pictures of the combustion chambers, sure. With the engine
off.
Go back and re-read what he wrote. YOU put words into his mouth when
you ASSumed "camera inside with engine running".

Maybe YOU should learn to read Elmo.

"They fitted cameras to the inside of the combustion chambers"

His words, not mine. Why in hell would they 'fit' cameras inside the
combustion chambers if they just wanted pictures of the combustion
chamber with the engine off. It would be a lot easier to pull the
head and photograph the chamber! If they used a fiber-optic camera,
fed through the sparkplug hole, then say that. Don't say you fitted a
camera. jezzz

Jack

[ben91932]

Post by Retired VIP
"They fitted cameras to the inside of the combustion chambers"

Combustion chamber viewing was used for the last 100 years to assess
fuel quality. Sir Harry Ricardo was the first to play with it on a
single cylinder variable compression engine with a 1" thick optical
micah viewing port. Pre-ignition and detonation were seen as yellow
colored, and led the the quantification of gasoline's detonation
properties via the octane-heptane ratio.
Many gasoline test engines (variable compression, viewing port with
high speed cameras) are still in use in industry and academia, but are
somewhat obsolete with the introduction of ultra-fast pressure and
temperature sensors and computer modeling.
hth,
Ben

[RT]

On Mon, 28 Jul 2008 13:02:09 -0700 (PDT), Built_Well

Post by Built_Well
Usually I get 24 miles to the gallon for stop-and-go city
driving with the '06 Camry LE, but this last tankful I got
28 city. I really babied the accelerator pedal this time
and, of course, have plenty of air in the tires. I had
Shell V-Power premium in the tank this time (for its
exceptional detergent levels), but usually I just put in
a regular grade.
I had Hy-Vee Grocery Store premium in there two tankfuls
back, and thought the car was idling kinda rough sometimes
while stopped, so I thought some Shell V-Power was in
order to help clean out any minute amounts of potential
gunk I might have gotten from the Hy-Vee gas.
When I asked him, the Hy-Vee manager said his gas met
the Top Tier standard, but Hy-Vee is not on the list
of Top Tier stations at toptiergas.com, so I doubt
Hy-Vee is Top Tier.
On Hy-Vee, the car once idled at only 600 rpm; I've never
seen it idle so low. Usually 650 to 700 is the lowest it'll
idle at. It could have been a coincidence that the one 600
idle happened under Hy-Vee.
"TOP TIER Gasoline is a new class of gasoline with enhanced
detergency. It meets new, voluntary deposit control standards
developed by four automotive companies - BMW, General Motors,
Honda and Toyota - that exceed the detergent requirements
imposed by the EPA.
"TOP TIER Gasoline keeps engine parts cleaner by reducing
fuel-related deposits, resulting in better performance.
A lower level of detergent may cause a buildup of deposits on
critical engine parts. These deposits can cause stalling,
rough idling, lowered acceleration and other unnecessary
problems in your vehicle--and your life.
* Improves fuel efficiency
* Prevents driving upsets (rough idle, hesitation, stalling
and surge)
* Improves acceleration
* Provides more power
* Reduces emissions
* Cleans dirty engines and keeps new engines clean
MFA Oil Company is proud to join industry leaders by requiring
TOP TIER Gasoline with higher levels of detergent in all grades
and every gallon of gasoline at Break Time Convenience Stores.
Link: http://www.mfaoil.com/index.cfm?show=10&mid=14&pid=4

Two tanks of the non-brand gas and you already have problems ? I think
it's all in your head.
hy-vee is not a gasoline manufacturer. They buy their gas from one of
the big names. There is nothing wrong with the gas, the only
difference could be in detergents. Results will only show up after
many many miles, if ever.
Buying higher grade gas than what the manufacturer of your car
specified is a waste of money.
If you really want to feel better , add a bottle of techron or seafoam
to your tank every 6 months and buy the cheap stuff.
The only gas I don't buy is from small gas stations that don't sell a
lot of gas. They might have old gas and cut corners when changing
filters in their pumps.

[Elmo P. Shagnasty]

Post by RT
Buying higher grade gas than what the manufacturer of your car
specified is a waste of money.

Define "grade".

Gasolines with good additive packages that include good detergents to
keep the fuel and combustion systems free of crap--now, those are good
grades of gasoline.

Funny thing--the manufacturer of your car doesn't specify what GRADE of
gasoline you should use.

I think you mean "octane" instead of "grade". Octane is not a measure
of "goodness". It's a measure of the fuel's ability to resist knock and
preignition. It's a property of the fuel--like color, it doesn't make
the fuel inherently "better" or "worse". It's just a property.

You've bought into the fuel company "premium" hype.

[RT]

On Thu, 31 Jul 2008 20:48:08 -0400, "Elmo P. Shagnasty"

Post by Elmo P. Shagnasty

Post by RT
Buying higher grade gas than what the manufacturer of your car
specified is a waste of money.

Define "grade".
Gasolines with good additive packages that include good detergents to
keep the fuel and combustion systems free of crap--now, those are good
grades of gasoline.
Funny thing--the manufacturer of your car doesn't specify what GRADE of
gasoline you should use.
I think you mean "octane" instead of "grade". Octane is not a measure
of "goodness". It's a measure of the fuel's ability to resist knock and
preignition. It's a property of the fuel--like color, it doesn't make
the fuel inherently "better" or "worse". It's just a property.
You've bought into the fuel company "premium" hype.

yeah yeah, I meant Octane.

[jim <"sjedgingN0sp"@]

Post by Elmo P. Shagnasty

Post by RT
Buying higher grade gas than what the manufacturer of your car
specified is a waste of money.

Define "grade".

Grade is a term used by the petroleum refining industry to classify
types of gasoline. Basically gasoline is pumped into pipelines for
distribution, The grading system is a way to determine the value of
the product so that exchanges and sales can be made. Octane is the
main criteria for determining each grade.

Most people agree that if you go below the octane requirements for a
given engine that your mileage will go down and if you purchase
gasoline that goes above the octane requirements you won't get any
benefit. That seems like a pretty simple proposition but in reality it
is a whole lot more complicated. It's complicated by the fact that you
really can't be sure what the exact octane requirements are with out
careful real world testing.

Post by Elmo P. Shagnasty
Gasolines with good additive packages that include good detergents to
keep the fuel and combustion systems free of crap--now, those are good
grades of gasoline.
Funny thing--the manufacturer of your car doesn't specify what GRADE of
gasoline you should use.
I think you mean "octane" instead of "grade". Octane is not a measure
of "goodness". It's a measure of the fuel's ability to resist knock and
preignition. It's a property of the fuel--like color, it doesn't make
the fuel inherently "better" or "worse". It's just a property.

I suppose you think there isn't any difference in quality of beef cuts
or that there is no such thing as "better" or "worse" when it comes to
types of wine?

Whether high octane is "better" or "worse" depends on what you are
interested in. Octane certainly is the single most important property
with respect to fuel economy. The reason the price is higher and
people pay more for premium is because A) It costs more to produce B)
In some vehicles it is cheaper to run using premium. C) regular may
cause damage to some vehicles. (note: I'm not saying B) applies to
every person who purchases premium and C) doesn't apply to very many
modern engines)

Here is a list what J.H.Gary's "Petroleum Refining Handbook" says
about the impact of octane on gasoline engines. The assumption here is
if everything else would be kept constant this is how these factors
affect a typical engine's octane requirements:

Combustion chamber deposits 0-12 RON
Altitude (air pressure) 3 RON for every 1000 ft.
Spark timing 3 RON for every 2 degrees
Engine speed 1 RON per 300 RPM
Engine Temperature 1 RON per 10°F
Intake air temp 1 RON per 20°F
Humidity 1 RON per 20%RH


He doesn't say anything about spark plug voltage and gap, EGR
concentration, and Air/Fuel ratio, or engine load which also are all
known factors that alter the engines octane requirements.
Engine management and it's sensors are designed to deal with a good
many of these factors so for instance timing is used to offset many of
the other factors. But sensors that measure these factors aren't
perfectly accurate or reliable. Just add up the possible normal
deviations and it is easy to see even in engines that are working 100%
as designed it is possible to deviate from the norm by more that 2
octane points. And what about the millions of cars that aren't
operating 100% as designed?

In isolation anyone of these factors is pretty simple to understand,
but when you combine everything together it becomes very complex
interactive system. Anyone (including the car's manufacturer) who
tells you they can predict with certainty what the effect of
purchasing higher octane fuel will have on any particular car's fuel
economy at any particular time or place is talking thru their hat.
There are just too many different factors beyond the scope of their
knowledge for such a statement to be anything but a guess.

-jim


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[Elmo P. Shagnasty]

Post by jim <"sjedgingN0sp"@

Post by Elmo P. Shagnasty
I think you mean "octane" instead of "grade". Octane is not a measure
of "goodness". It's a measure of the fuel's ability to resist knock and
preignition. It's a property of the fuel--like color, it doesn't make
the fuel inherently "better" or "worse". It's just a property.

I suppose you think there isn't any difference in quality of beef cuts
or that there is no such thing as "better" or "worse" when it comes to
types of wine?

You would be mistaken, just as you're mistaken when you compare cuts of
beef to gasoline.

[Elmo P. Shagnasty]

Post by jim <"sjedgingN0sp"@
Anyone (including the car's manufacturer) who
tells you they can predict with certainty what the effect of
purchasing higher octane fuel will have on any particular car's fuel
economy at any particular time or place is talking thru their hat.

yeah. Gee, you're right. Honda's engineers are pretty much stupid, and
don't know anything.

Sure. Uh-huh.

[jim <"sjedgingN0sp"@]

Post by Elmo P. Shagnasty

Post by jim <"sjedgingN0sp"@
Anyone (including the car's manufacturer) who
tells you they can predict with certainty what the effect of
purchasing higher octane fuel will have on any particular car's fuel
economy at any particular time or place is talking thru their hat.

yeah. Gee, you're right. Honda's engineers are pretty much stupid, and
don't know anything.

No. If you had ask I would respond that Honda's engineers are among
the best. But as far as I know all that they say about mileage
estimates on their vehicles is something to this affect: "Your actual
mileage may vary".
It would be pretty pointless for the engineers to enter into a
technical dialog with customers about the numerous factors that
contribute to the wide range of mileage that their customers get from
the same make and model vehicle. I mean look at your response - it
appears the only thing technical that you were able to grasp and
respond to was the analogy I made between grades of beef and grades of
gasoline.

-jim


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