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Re: octane rating

Shell's premium fuel is 93 octane. However I have heard it is not necessary to run the 93 octane as most cars will do just fine on the 89. I haven't picked up my GTI yet...picking it up this weekend. But my BMW runs just as well on the 89 octane from shell. Stay away from the BP gas since the cleaning agents in the fuel cause problems over time to fuel injectors, etc.
 

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Re: octane rating

DrJones said:
Low octane gas in a high compression of forced induction motor can created a condition of early ignition called detontation. When the fuel-air mixture ignites before it's supposed to, the downforce placed on the piston before it completes it's upstroke can cause serious damage to the motor. While this condition is rare, it is a possibility. The motor in the GTI is designed to run best on 91 octane gas.
As for the detonation it is rare like you say and cars these days have anti-knock sensors to prevent this from happening. If detonation does happen you will know it's going on...by your fast yelling from under the hood!

I think it's safe to say you can cheap it out at the pump on the mid-grade but you will pay for it in performance. It' depends on how hungry your fast is an how expensive of a dinner you want to buy it.
 

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Re: Octane Mixture

tikiman said:
MINE SAYS 91 BUT IVE ONLY USED 93...THE SALESMAN SAID THAT I COULD USE 89 AND IT WOULD ONLY HURT THE PERORMANCE, HE SAID THAT THE CAR WILL "DETUNE" SOMEHOW BY ITSELF
Correct, You won't hurt your engine by running 89. You'll just hurt your performance. Every once and a while though I would run 93 through it.

For the record I have only pumped 93 so far. But then again I have only filled up a couple times so I have no idea what kind of performance loss you would have. Most people probably won't notice the 10-15 hp loss running a lower octane.
 

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Re: Too high of octane??

I wouldn't run anything higher than 93/94 octane that you can get at the corner pump. 100 octane fuels will damage your parts with extended use. The stock engine doesn't have the appropriate components to handle the higher octane in addition to making any extra power with the higher octane.
 

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Re: Too high of octane??

Aldin20 said:
dem yo here in chicago 87 is like $3.25 a gallon and 93 is like $3.50 a gallon depends what gas station u go to
Head out to the burbs and save yourself 20 cents a gallon. Or hit Indiana for cheap fuel, cigs, and beer. >:D
 
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