Car Talk and premium gas

[-rick-]

Did any one happen to catch Car Talk last Saturday where
they advised (I'm paraphrasing) that it was a waste of money
to use premium gas. I expected some qualifications to
follow but they left it as a broad truism that the knock
sensor would prevent damage and made no mention of reduced
efficiency or performance.

Does any one know of any valid data to support or refute
their claim?

 

[houndman]

Did any one happen to catch Car Talk last Saturday where
they advised (I'm paraphrasing) that it was a waste of money
to use premium gas. I expected some qualifications to
follow but they left it as a broad truism that the knock
sensor would prevent damage and made no mention of reduced
efficiency or performance.

Does any one know of any valid data to support or refute
their claim?

I heard it and was puzzled, but then I don't know the new electronics
and the like. Would like to hear what people have to say.

Maybe asking on their web site would bring clarification.

 

[B A R R Y]

Did any one happen to catch Car Talk last Saturday where they advised
(I'm paraphrasing) that it was a waste of money to use premium gas. I
expected some qualifications to follow but they left it as a broad
truism that the knock sensor would prevent damage and made no mention of
reduced efficiency or performance.

Does any one know of any valid data to support or refute their claim?

Read your owner's manual for what you should use in your vehicle.

Cars that require or "recommend" premium often run more efficiently or
more powerfully on premium. Cars that recommend regular (most cars)
usually get zero benefit from higher octane, so premium is simply a
waste of money. Here in the most highly marketed-to-in-the-world North
American society, we tend to buy into the "upscale" mentality of more
expensive = better.

I have MPG data from every tank of gas for my 2005 Tacoma in Quicken.
Toyota recommends premium for the 4L V6. If I spend the ~$0.30/gal
extra for premium, I get enough extra miles to actually make it
slightly cheaper per mile than regular, and get better performance under
stress (towing and hot / higher atmosphere) as a freebie!

My '99 Wrangler and 2001 H4 Subaru got exactly the same mileage and no
noticeable performance gain on 87 vs. 91+, so premium was a complete
waste of money.

Cars that _require_ higher octane in the manual can be damaged by lower
octanes, and should not be run on regular.

 

[bigjim]

Premium is a waste of money. Yes performance may suffer but not for a
daily driver. No damage will result. What if premium isnt available.
Do you really think your car will explode if you use regular? I have
personal experience with a 2001.5 Passat that "required" premium
fuel. Never used it and car ;lasted 140k + before tradein. None of
the numerous mechanical problems car suffered could be attributed to
gas . You are free to give oil companies more but I wont

 

[KLS]

Read your owner's manual for what you should use in your vehicle.

Cars that require or "recommend" premium often run more efficiently or
more powerfully on premium. Cars that recommend regular (most cars)
usually get zero benefit from higher octane, so premium is simply a
waste of money. Here in the most highly marketed-to-in-the-world North
American society, we tend to buy into the "upscale" mentality of more
expensive = better.

I have MPG data from every tank of gas for my 2005 Tacoma in Quicken.
Toyota recommends premium for the 4L V6. If I spend the ~$0.30/gal
extra for premium, I get enough extra miles to actually make it
slightly cheaper per mile than regular, and get better performance under
stress (towing and hot / higher atmosphere) as a freebie!

My '99 Wrangler and 2001 H4 Subaru got exactly the same mileage and no
noticeable performance gain on 87 vs. 91+, so premium was a complete
waste of money.

Cars that _require_ higher octane in the manual can be damaged by lower
octanes, and should not be run on regular.

Thank you for this excellent post. You said it far better than I
could, especially with your empirical evidence to back it. I don't
know why people buy cars that require premium gas and then don't feed
the cars properly. Why did they buy those cars, then?

 

[bigjim]

I buy a car for the car- style, design, capabilities, utility etc.
Gas is gas so I dont consider it.

 

[Rick Courtright]

Cars that require or "recommend" premium often run more efficiently or
more powerfully on premium. Cars that recommend regular (most cars)
usually get zero benefit from higher octane, so premium is simply a
waste of money. Here in the most highly marketed-to-in-the-world

I have MPG data from every tank of gas for my 2005 Tacoma in Quicken.
Toyota recommends premium for the 4L V6. If I spend the ~$0.30/gal
extra for premium, I get enough extra miles to actually make it
slightly cheaper per mile than regular, and get better performance

Hi,

Barry already said everything that was going thru my head. My old Subie
says "regular" and only during the very hottest months of summer have I
been able to see any difference when I've tried "higher" grades (cuz it
pinged like crazy.)

OTOH, a slightly newer 3.0l V-6 Camry sitting on the driveway will run
on anything, but DOES do better, as the book says it will, by going to a
higher grade just as Barry's Taco does. I assume it's got a lot to do
with improving fuel and engine management systems as the years go by?

Rick

 

[B A R R Y]

I have
personal experience with a 2001.5 Passat that "required" premium
fuel. Never used it and car ;lasted 140k + before tradein.

A sample of one, in sea level NJ. <G>

 

[Fuzzy Logic]

Did any one happen to catch Car Talk last Saturday where
they advised (I'm paraphrasing) that it was a waste of money
to use premium gas. I expected some qualifications to
follow but they left it as a broad truism that the knock
sensor would prevent damage and made no mention of reduced
efficiency or performance.

Does any one know of any valid data to support or refute
their claim?

It's generally considered a waste IF the manufacturer recommends regular fuel. If the owner's manual states
premium fuel you should be using it. Here is an article on this topic:

http://www.canadiandriver.com/articles/jk/040728.htm

 

[JD]

It's generally considered a waste IF the manufacturer recommends regular
fuel. If the owner's manual states
premium fuel you should be using it. Here is an article on this topic:

http://www.canadiandriver.com/articles/jk/040728.htm

I can tell you that an STi can produce audible pinging on 91 on a hot day
from experience; because the base timing is reached and it can't be retarded
further. Just about every automotive source indicates that audible pinging
in a modern engine with a knock sensor usually means damage is occurring.
Given that, I only use 93 or better in the STi, and drive sedately on 91 in
the summer. So, you can bet regular would definitely damage the engine if
driven hard.

 

[bigjim]

Yu are free to keep inflateing oil company profits. Pinging is
normal and indicates maximum efficiency

 

[Clive - Selectron]

Pinging is fuel detonating, not burning smoothly and not normal.
That is bad.
If pinging is present in an engine, excessive amounts of heat and stress are
generated and will cause destruction of engine components such as pistons
and valves.
I'd check that out if I were you....try Google....don't take my word for it.
As a rule (in the UK) the higher octane fuels we have (95 to 102) also have
detergents and other additives to keep the fuel system clean which is an
additional benefit.
My WRX most certainly runs better on 99 (+5% bioethanol) than 95 so better
all round, a little greener and who cares about a few pennies extra per
litre for a top quality product?
-C-

 

[Rick Courtright]

Yu are free to keep inflateing oil company profits. Pinging is
normal and indicates maximum efficiency

Hi,

Methinks you've got it a bit off: maximum efficiency comes JUST BEFORE
pinging according to all sources I've ever researched. Pinging is
uncontrolled, therefore it's hard to believe it's efficient!

Rick C

 

[Fuzzy Logic]

(e-mail address removed) wrote in

Yu are free to keep inflateing oil company profits. Pinging is
normal and indicates maximum efficiency

Not unlessyou are using a Bourke engine <http://en.wikipedia.org/wiki/Bourke_engine>

Pinging aka detonation is not good for conventional internal combustion engines:

It is caused by an instantaneous ignition of the remaining fuel/air mixture in the form of an explosion. The
cylinder pressure rises dramatically beyond its design limits and if allowed to persist detonation will damage
or destroy engine parts.

 

[JD]

Pinging is NOT normal and it is not good for the engine. If you think
otherwise, go read some more.

 

[Phil]

Pinging is normal and indicates maximum efficiency

What the fk ???

 

[bigjim]

A vehicle is at maximum efficiency at the stage right before pinging

 

[JD]

A vehicle is at maximum efficiency at the stage right before pinging

And is in a danger zone once pinging starts. Pinging is NOT normal and
extremely distructive.

 

[Phil]

Pinging is normal and indicates maximum efficiency

A vehicle is at maximum efficiency at the stage right before pinging

It may well be, but that's not what you said.

 

[bigjim]

My 94 Trooper manual said something like "occasional light pinging
upon accelleration indicates vehicle is at optimum efficiency" .
Truck occasionally pinged and lasted 140+k miles before it was hit and
totalled. Engine appeared to have much life in it so I cant accept
there was any "damage".