I can get 100 octane racing gas in my area. although it is 3.50 a gallon.I was thinking of taking my car to the strip to see what i can get out of it.Will the engine hold higher boost levels on 100 octane or is anything above 93 a waste of cash?

 

No it won't hold higher boost, but you could turn up the boost a little more without detonation. You still shouldn't try to exploit race fuel without proper tuning tools. It will probably give you more agressive timing and that will help your times some. The Evo already runs so rich up top that it really doesn't need race gas in stockish trim.

 

way rich dont use race gas only after many stages of upgrades or road racing..

 

Stages.

 

Read this thread, and many more on the subject. I tried it and it works.

After reading alot online about Homebrewed Octane boosters and seeing the results from the Work Perfornce Dyno runs and the 18hp difference between 91 and 93 octane in the EVO; I ran down to the local Sherwin Williams and bought 1 gal of Toluene and 1 gal of Xylene, added them to 1/2 tank and topped it off with 91 gas.
After the old gas was run out of the lines I dropped the hammer...WOW,
I really noticed an extra rush on the top of the RPMs. It pulled hard and fast, redline came faster than normal (only 91).
I ordered a 5 gal can of Toluene. I know it's really not feesable the run this all the time. But when I want to go out and run it, I can just drop in a couple gallons of this "wonder juice".

The formula for what I did is: (12gals X 91oct) + (1gal X 117oct (Xylene)) + (1gal X 114oct (Toluene)) / 14gals = 94.5 RON, using only Toluene = 94.28 RON. Toluene is cheaper.
Check out these sites:
http://www.gnttype.org/techarea/misc/octanebooster.html
This site is very informative:
http://forums.audiworld.com/s4/msgs/95187.phtml

 

There has to be a catch! I'll test it on my brothers S4.

 

damn where do you live
3.50 for 100 oct its 5.00 by be in jersey

 

Chicago il area

 

gas is gas

 

Insightful.

 

About 4.50 here in So cal

 

You are joking, correct?

 

Unless of course you're burning the ever powerful... RICE. Am I right RICEBURNER221? Is the brown a higher octane that the white, I forget?

 

Where in Chicago is it (specifically please). Make sure it is unleaded race gas. Some isn't and will ruin your emissions systems.

 

I'm assuming he's talking about this:
http://www.racegas.com/gt100locals/default.asp

They're nice if there is a location near you. Too bad they're not in Texas anymore.