Car Talk and premium gas

[JD]

You are an annecdote of one. In most vehicles requiring premium
(performance vehicles) damage definitely does occur.

 

[bigjim]

That's what warranties are for! NO car maker will produce a car that
is damaged by regular gas. Otherwise they would be replacing engines
left and right. What would happen if you were in the sticks and only
regular was available? Will your car be damaged? NO!!!!! MPG
and0-60 may suffer but no damage will result. Buy me an FJ cruiser
and I will only use regular- guess what I'll still reach 100k+
miles. Plus save a bundle!!!

 

[JD]

Modern ECUs can tell what kind of gas you have been running by the amount of
retard on the timing combined with the number of times the knock sensor
activated. If the timing hits base and the knock sensor still fires, the
fuel grade was too low. Guess what? No warranty from any resulting engine
damage even if had nothing to do with the fuel.

 

[hippo]

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?

Here in Oz, current unleaded fuel grades are 91, 95 & 97 RON, with or w/o
ethanol. *Everything* post 88 is required to accept 91RON *but* a
significant (and increasing) number of cars specify minimum 95 or 97 and
*will* show decreased performance &/or economy with the base grade.

My 99OB is recommended for 91. Ditto 02 2.4 Camry and an 83 carburettor
Nissan my daughter owns. On these and many others higher grades make NO
difference except higher cost. OOTH, pre EFI cars can suffer catastrophic
damage from pinging/detonation over not too great a time.

My 81 Saab turbo requires min 97RON, copes with 95 ethanol, sulks a bit on
straight 95 and runs like rubbish on 91 on all but eggshell throttle
openings! By contrast, 85+ APC Saabs will run ok on everything from kero
upwards - min 86RON IIRC.

Anything post unleaded will run on base grade, but if it specs premium,
then there *will* be a performance tradeoff running a lower grade. If you
just noddy around it may not show up. If you back off when it starts
pinging its head off you won't do any damage, *but* it's all a bit like
the old so called "motorbike mechanic's torque wrench" method - tighten it
'til it strips then back it off half a turn! If you're running through
hills with a full load plus the air and sound on, I doubt if you'd know it
*was* pinging until something broke!

Maybe better to just pay the money or select a different car in the first
place? Cheers

 

[JD]

Here in Oz, current unleaded fuel grades are 91, 95 & 97 RON, with or w/o
ethanol. *Everything* post 88 is required to accept 91RON *but* a
significant (and increasing) number of cars specify minimum 95 or 97 and
*will* show decreased performance &/or economy with the base grade.

My 99OB is recommended for 91. Ditto 02 2.4 Camry and an 83 carburettor
Nissan my daughter owns. On these and many others higher grades make NO
difference except higher cost. OOTH, pre EFI cars can suffer catastrophic
damage from pinging/detonation over not too great a time.

My 81 Saab turbo requires min 97RON, copes with 95 ethanol, sulks a bit on
straight 95 and runs like rubbish on 91 on all but eggshell throttle
openings! By contrast, 85+ APC Saabs will run ok on everything from kero
upwards - min 86RON IIRC.

Anything post unleaded will run on base grade, but if it specs premium,
then there *will* be a performance tradeoff running a lower grade. If you
just noddy around it may not show up. If you back off when it starts
pinging its head off you won't do any damage, *but* it's all a bit like
the old so called "motorbike mechanic's torque wrench" method - tighten it
'til it strips then back it off half a turn! If you're running through
hills with a full load plus the air and sound on, I doubt if you'd know it
*was* pinging until something broke!

Maybe better to just pay the money or select a different car in the first
place? Cheers

That may be true in Oz, but not neccesarily in NA. If you do not run the
correct grade of fuel here, and there is engine damage (even if not directly
related) they won't honour the warranty. Also, NA-spec cars are different
than the rest of the world.

For example, the STi. It recommends 93. The user manual tells you in the
absence of 93, you can use 91. However, no lower grade should be used. In
many places in NA, 93 is not available. I can tell you from experience that
the STi will ping on 91 on warm day, and since I have the car instrumented,
I can also tell you that timing reaches base when that happens. It can no
longer compensate.

 

[bigjim]

Cite an actual case where a warranty was denied based on fuel use.
Should a dealer hedge n warranty repair (none will), Simply claim gas
was low and the only nearby gas was regular. If they continue to
stall a call to the local troubleshooter/consumer advocate will get
the dealer and the car maker negative publicity they do not want. The
whole premium requirement is a crock. Again, buy me a new FJ cruiser
and I will never use premium. Any warranty issues will be dealt with
by Toyota with no problem and the vehicle will last me the average of
8 years I normally keep a vehicle. If youre so convinced that damage
will result,step up and put your money where your mouth is. You wont
do it because 1. You know I'm right. 2. You'll feel bad that I'm
enjoying a cool vehicle and saving gas money.
People buy premium to feed their egos and because they dont know
better. Would the car maker provide towing if you were in Nowhere MT
and the only gas for 200 miles was regular? Doubtful.

 

[JD]

I don't need to. Read the friggin warranty guide for a WRX or an STi.

Secondly, even if you are right (which you're not) you won't save money
because the reduction in gas mileage and performance will more than offset
the slightly higher cost of premium fuel.

There are a variety of ways in which a car can be 'detuned' to run regular.
Cobb AP on economy mode is one. If you install an AP it will void your
powertrain warranty; there are TONS or real-world examples of that
happening.

 

[Bonehenge (B A R R Y)]

and I will never use premium. Any warranty issues will be dealt with
by Toyota with no problem and the vehicle will last me the average of
8 years I normally keep a vehicle.

Your loss!

I have the same engine in a Tacoma. Premium is recommended, not
required, so you really don't have to use it. Warranty coverage will
not be an issue as far as 87 octane goes.

Where you'll lose is never getting to enjoy the full potential of the
engine, as well as an overall lower cost per mile for fuel. That's
right, premium is cheaper!

 

[bigjim]

Yes detuning re-tuning, chips etc may cause a dealer to question
whether or not car was abused or raced and they may try to weasel out
of a major repair. However , I doubt the WRX STI manuals say clearly
in bold letters "The use of less than 93 octane gas WILL result in
engine damage and disclaiming of warranty" It likely mentions nothing
of damage. I only have the outback manual. I will look and see if
there is mention of engine destruction with the 3.0 which asks for
premium. I doubt it.

 

[JD]

Yes detuning re-tuning, chips etc may cause a dealer to question
whether or not car was abused or raced and they may try to weasel out
of a major repair. However , I doubt the WRX STI manuals say clearly
in bold letters "The use of less than 93 octane gas WILL result in
engine damage and disclaiming of warranty" It likely mentions nothing
of damage. I only have the outback manual. I will look and see if
there is mention of engine destruction with the 3.0 which asks for
premium. I doubt it.

I have the manual in front of me. It says:

"Your car requires the use of premium fuel of 93 octane or better. If 93
octane is unavailable, 91 octane may be used temporarily. Driveability may
be affected. Use of lower grades of will result in poor driveability and may
result in engine damage."

I don't know how much more clearly it could be stated.

 

[bigjim]

"may result in damage" Just like alchohol may cause health
problems. . Any warranty mention ?

 

[JD]

It doesn't matter. It quite clearly mentions the possibility of damage from
wrong fuel types; which is what just about everyone has been telling you.
The warranty is not mentioned in the Owners Manual at all. It is a separate
guide. It is more of what is not covered by both the OEM and the extended
warranty. But it does state that if the vehicle is not used or maintained
within the parameters recommended by Subaru that the warranty may be voided.

Think about it for a second. The warranty is to cover manufacturer's
defects and premature failures, not failures due to misuse or incorrect use.
You wouldn't have a leg to stand on.

 

[hippo]

It doesn't matter. It quite clearly mentions the possibility of damage from
wrong fuel types; which is what just about everyone has been telling you.

The warranty is not mentioned in the Owners Manual at all. It is a separate
guide. It is more of what is not covered by both the OEM and the extended

warranty. But it does state that if the vehicle is not used or maintained

within the parameters recommended by Subaru that the warranty may be
voided.

Think about it for a second. The warranty is to cover manufacturer's
defects and premature failures, not failures due to misuse or incorrect
use.
You wouldn't have a leg to stand on.

Yeah, but if the man wants to buy a new vehicle cos he thinks it's cool
then have to drive like a granny so he can scrimp pennies by buying the
cheapest fuel around then that's his choice I say! FWIW, if I could afford
an STi - and do without the wagon - I think I'd take the fuel requirement
as a necessary cost and have a grin on my face anyway, same as with the
bike.
Cheers

 

[KLS]

Yeah, but if the man wants to buy a new vehicle cos he thinks it's cool
then have to drive like a granny so he can scrimp pennies by buying the
cheapest fuel around then that's his choice I say! FWIW, if I could afford
an STi - and do without the wagon - I think I'd take the fuel requirement
as a necessary cost and have a grin on my face anyway, same as with the
bike.

My attitude exactly; well said!!!!

 

[JD]

Yeah, but if the man wants to buy a new vehicle cos he thinks it's cool
then have to drive like a granny so he can scrimp pennies by buying the
cheapest fuel around then that's his choice I say! FWIW, if I could afford
an STi - and do without the wagon - I think I'd take the fuel requirement
as a necessary cost and have a grin on my face anyway, same as with the
bike.
Cheers

That's how I feel. I didn't buy the thing for economy. I have the daily
driver for that.

However, every now and again we get the question as to whether you can burn
low-grade gas in a high-performance engine. The answer is, of course, no.
But if someone is asking, it means they don't know and so I can't let go
when I see someone give those people a bullshit answer that could leave them
in a real pickle.

 

[bigjim]

You continue to mouth the myth that an engine will destruct if regular
gas is used. Unknowledgeable people will buy this and feel they MUST
pay extra for gas. Myself, I would never buy a car that "required "
premium just because I know its a crock and my idea of high
performance is a V8 not a 4 cyl. I also will not buy a car that I
cannot do an oil change and basic maintenance on. But there will be
no damage so people just use the gas they want and if there is no high
octane engine will not die.

 

[Carl 1 Lucky Texan]

You continue to mouth the myth that an engine will destruct if regular
gas is used. Unknowledgeable people will buy this and feel they MUST
pay extra for gas. Myself, I would never buy a car that "required "
premium just because I know its a crock and my idea of high
performance is a V8 not a 4 cyl. I also will not buy a car that I
cannot do an oil change and basic maintenance on. But there will be
no damage so people just use the gas they want and if there is no high
octane engine will not die.

high performance (as it relates to acceleration) is high power to weight
ratio. NOT 'V8' . PLENTY of vehicles are high performance with fewer
than 8 cylinders.

And, since many people agree with you and would not buy a car that
required premium fuel, there is a big incentive for manufacturers to
point out the fact that their cars are designed to run on low octane
fuel IF THAT'S THE CASE! So, why recommend mid or high octane? because
that is what the car is DESIGNED to be operated with.

Do you run straight 20W oil? Don't wanna give the oil companies too much
money, remember? ;^) It might be cheaper and your car will likely run
for 150k or more miles with it. BUT - with the PROPER oil it may run for
200K or more. Using low octane and getting 'slight' pinging on occasion
may be in teh same caetgory of long term, 'slow death'.

Carl

 

[JD]

Good for you. If a V8 is your idea of high performance, that's cool. Most
of them don't require high octane fuel. Generally, it is high-compression
or forced-induction engines that require it. If you would never buy premium,
at least you don't buy a car requiring it. Those of us liking small, nimble
cars with small but high horsepower engines, get forced-induction or
high-compression; which require premium. Its no myth.

Incidently, I always use the fuel for which my car is designed. I generally
get 350,000 KM (210,000 miles) out of my cars and I sell them still working
fine.

 

[bigjim]

To me 4 cyl are economical and regardless of how quick a car might be
there is nothing like the rumble of a v8.
Oil costs the same so weight is not a factor in cost. Longevity is a
matter of design and maintenance not oil weight or cost. My 86 Dodge
daytona got whatever oil was cheapest. Ran over 100k but dodge
quality came into play and it was needing ,major work (not engine).
94 Trooper used syn blend and ran to 140+k til hit. 04 outback used
full syn since about 7k. Usually walmart super tech - $13 for 5 qts
SL rated full syn. I have no doubt I can get high mileage out of
subie but will probably trade next year if Wrangler Unlimited is sold
in yellow or better colors than available now and to allow kinks to be
worked out. If someone wants to put premium in their car thats
fine. It just bothers me when some people who are trying to feel an
ego boost " my car is high performance" are led to believe "damage
will result" which is just not true. Does slight occasional pinging
cause damage? Probably not IMO. If I get 8+ years from a vehicle
with no major repair bills, I'm happy. After a point I choose to buy
a new car rather than put money into an old one but thats my choice.
I just cannot in good conscience give those oil companies a cent more
than I have to. Iwalk and cycle to handle most errarnds. so I will
not buy a higher grade of gas for $3-5 a tank extra.

 

[nobody >]

You continue to mouth the myth that an engine will destruct if regular
gas is used. Unknowledgeable people will buy this and feel they MUST
pay extra for gas. Myself, I would never buy a car that "required "
premium just because I know its a crock and my idea of high
performance is a V8 not a 4 cyl. I also will not buy a car that I
cannot do an oil change and basic maintenance on. But there will be
no damage so people just use the gas they want and if there is no high
octane engine will not die.

You sound like a parrot.

I mostly agree with you but you can't see the exceptions worth shit.

My '00 OBW *doesn't* spec higher octane fuel. With a 10 to 1
compression ratio, that's pushing it. I've found that 89 over 87 gives
me about a half-mile per gallon better, so if 89 is 10 cents or so more
than 87 I fill it with 89.