If the car is completely stock, you won't feel anything at all. Race gas by it's self doesn't give you any more power (unless you are already getting knock). However, it does allow you to safely turn up the boost and/or advance timing, which definately adds power. If you are not changing anything with the stock tuning, it really has no benefit.

 

Now there is someone putting some reasoning to "when" it wont effect it that much. Good post! If he was running 100oct fully or had very little pumpgas in tank and filled up with 100 oct there would be "possibility" to lose power, however sure a 50/50 mix i dont think would see much ill effect.

 

Then what is the Highest/ safest boost I can go on with 100ct? [22psi?]

 

Absolutely not true. Changing octane will not directly affect the AFR. Changing the boost will not directly affect the AFR.

 

You don't need to mess with boost. If you run your car at the dragstrip with 91 octane and then go back and run it with 91+100, you will may run a tenth or 2 quicker with the added race gas. Why you ask? The 91 octane may not be enough for the stock ECU to run full timing advance it is capable of. Once you put the higher octane in, reset the ECU and it may learn that it can run a bit more timing before the knock signal gets too high.

To answer the question "How much boost can I run on 91+100" :
You can run as much boost as possible while staying under X amount of knock.

That is the only true answer to that question. The only way to know for sure is to raise the boost, do a run and log knock. Raise it some more, log the knock. At some point point your knock will go up. Then you will know what is too much for that gas on that day.

EVOlutionary

 

91octane x 10 gal = 910
100octane x 4 gal = 400
=1310

1310/14gal(total in tank)=93.5octane

formula to figure out your octane rating. Just change the #'s based on the amount of fuels you are mixing.

 

But aren't evos supposed to get 93 Octane minimum? Aren't we in California forced (unless you have high octane available close by) to run suboptimum gas? So won't this be giving your car what is was designed for? I admit 100% 100 octane may be a bit much for a stock car on the street but blending it seems like good insurance against knocking and a better solution than octane boosters.