100 Octane (Race Fuel)
 

Hey Everyone,

I ran into something interesting today. A Sunoco near me seems to sell SS100 or 100 octane "race" fuel. Has anyone ever try running this high octane fuel? Any interesting effects or problems?

On a stock FA20 motor with a factory tune, the 100 octane would be a waste of money (of no real benefit....and it would probably hurt your gas mileage). Anything above 94 octane on the stock tune would seem to be overkill unless you were boosted or tracking the car in 100 degree heat.

I've been running 100 octane on the track for the extra protection against detonation. Would highly recommend it for that, but not needed on the street for a stock engine.

Could you please elaborate on why this is the case? Is it due to the electronics pulling back to provide a certain performance output?

I asked because I've read the electronics keep a tight leash on the engine parameters and wonder if it would self regulate output regardless of the energy level provided by the fuel. ie - pull back for higher octane fuel and kick it up for lower grade fuel.

The ecu will pull timing if it senses knock. If there is no knock it leaves the timing where the factory set it. If you put in a higher octane fuel that doesn't make more power. You would have to add timing to make more power. You just made it less likely to see detonation.

Why not run an e85 tune?

Higher octane fuel does NOT contain more energy or make more power...it only has a higher detonation threshold.

BTW, I think you'll find that the 100 octane is LEADED fuel, an absolute no-no for catalyst equipped engines.

The sunoco here that sells 100 octane is unleaded. And quite expensive

the Sunoco down the road has 100 at the pump. its great for when you know you are gonna go beat on a boosted car. :burnrubber:

Since I can't get 93 here I just mix 100 with 91 to achieve 93, quiets the crickets just a bit