Re: Camry I4 + Supreme gaz = danger??

On Sun, 3 Sep 2006 11:52:21 -0400, "cimetiere"
<cimetiere@xxxxxxxxxxxxxxxx> wrote:

Hi! A few weeks ago, I read in a NG (I don't remember if it is this one, if
so, please accept my apologize to bring this issue back!) that cars that
toyota recommends to use regular fuel should not use supreme since the
octane is too high and the engine would not be able to burn it efficiently,
therefore could damage it in the long run.

Is this true? Should it not be true, I have a second question: is it
worthwhile to use supreme fuel (does it last longer, is it cleaner, etc.?)
or is it a waste of money?

On cars built within the last 10 years with EFI and knock sensors,
you can run regular fuel when you are driving easy around town, and
the engine will knock back the timing to compensate.

Read the wording in the Owner's Manual carefully, it will say
something like "For best performance you should run 91/92 Octane
Premium, but you can run on 87 Octane if you want, with diminished
performance." Not an absolute.

You will get a bit better fuel mileage on Premium because of the
slight power boost, but when you consider the price bump for Premium
at best it's a wash. Run 89 mid-grade around town if you are worried.

But if you are taking a trip and plan to push for time and go
blasting up mountain passes with the car fully loaded, run the good
stuff. As soon as the computer notices the lack of knocking, it'll
bump the timing and give you that little extra kick in the tuchis.

WARNING: If you have an older car (carbureted or first-generation
EFI without the knock sensor and sophisticated fuel and timing
control) and they say to run Premium, you run Premium, Period.

The mechanics can only compensate so far for garbage fuel when
setting the timing by hand - and if they set the timing while it has
Premium in the tank it will be way off if you switch over to Regular.
The engine will happily knock hard (called detonation) and beat itself
to death when you push hard. And when you punch a hole in a piston or
two it's a rather expensive thing to fix.

--<< Bruce >>--

.

Relevant Pages

  • "Premium" Fuel - Con?
    ... Don't pay for premium ... An RACV study shows that most cars don't benefit from more expensive premium ... Oil companies claim filling up with premium unleaded petrol, ... lower fuel consumption and higher performance. ...
    (uk.rec.driving)
  • Re: Better than Lincoln... except for the hypocrisy
    ... E85 is a less efficiently burning fuel than what sort of ... High-octane, standard, premium, leaded ... Nearly impossible with today's cars. ...
    (alt.smokers.cigars)
  • Re: MPGs...Do you really get what you pay for?
    ... Myth If regular-grade fuel is good, ... Reality Most vehicles run just fine on regular-grade fuel. ... Using premium in these cars won't hurt, but it won't improve performance, either. ...
    (rec.outdoors.rv-travel)
  • Re: 1991 Passat Wagon 2.0L/5speed
    ... The fuel door sticker is long gone and I didn't get an owner's ... I believe that with lower octane fuels, ... cheaper premium is on a percentage basis. ...
    (rec.autos.makers.vw.watercooled)
  • Re: Shortwave for cars?
    ... It's not too difficult to bring older vintage cars up to reasonable emission standards but then the analists will question their "authenticity. ... Have a look at the rest of the world where fuel is hellishly expensive so performance, efficiency AND fuel economy go hand in hand. ... Engine efficiency depends a lot on volumetric efficiency and the maximum volumetric efficiency can occur at either high or low rpm depending on engine design. ...
    (rec.radio.shortwave)