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

 

Also if u wanted u can go look on unical76's website and look for a local 76 that sells 100 octane and add to the tank of gas to make your own blend

 

wow, this sounds really promising, been looking for solutions for the stupid 91 has, racing gas would empty my wallet so maybe this could help me out afterall, great post, thanks

 

evoturbo131: hey, went by your shop about a week ago, but you weren't there. Moved to Sac on Thursday. ANyway, check out the WORKS ECU re-flash. I love runnning some race gas, but that's gonna get expensive over time. Sounds like the WORKS setup might be a great solution i/o race gas to help us out with this 91 octane ****. Especially since they are right there in SF... you should go down and talk to their engineers, see what you think.

 

yea actually i was browsing through their site, and it sounds coo, i might actually do that. i'm waiting over at vishnu to see when they will be done with their ecu re-flash project, so i'll see who i should work with. did you get the WORKS ecu yet? let me know if you go by there.

 

Wow, sounds really good! This is where switchable maps would be so wonderful. Id say buy an extra ECU meant for different setups.

 

I just added 2 gallons of Xylene to my tank and filled her up with 91. So I should be almost at a 95 octane rating. I am going to reset my computer and see how she runs. I paid 7.95 per gallon at Sherwin Williams. Kind of pricey. I am sure that I can find it cheaper elsewhere. This equals to about a 15% mix, so I should still be within the limits. Next time I will probably mix it with some ATF for lubrication.

 

Its hard i've tryin'g to look around for cheaper xylene or toulene other then sherwin williams. For me right now, i mix 1.2 gallons of 100 racing gas and about .6 gallons in other to reach 93+ . If you want its always safe to mix 100 to your mix right now, so you don't have too much xylene in your car

 

I ran a half tank of the xylene mix through the car so far. It is running alot smoother and wants to pull even past redline and I mean it pulls alot harder. I was impressed with the results. I wish I could get 100 around here at the pump, but for me I have to pay 6.95/gallon for C12 or 7.95/gallon for C16 at the local perfomance shop. I will not do this every tank though, only when I am going to a dyno are the track.
I will be on the East coast by March are sooner with the higher rated gas, so I wont have to put up with the 91 mix anymore. Thought I would just try it to see how it would work.
I am impressed with the results though.

 

C12/c16 are leaded fuels... will eventually screw your o2 and cat?

 

Thanks for the info. Soon I will be running a cat delete pipe. Will just one gallon affect the o2 senor that much and will it affect a nice wideband sensor? Just curious. I don't want to put leaded fuel in my car anyways.

 

I have read a few reports on the subbie and skyline forums of a few runs with leaded gas plating the 02 sensor and rendering it useless. With the cost of a wideband ... I would not risk it.

 

Here's some more info on the Sunoco fuels:

http://www.racegas.com/fuelspecs/default.asp

 

Also I just located 100 octane Sunoco GT100 here in Rochester. It's sold at a few select Delta Sonic locations, namely West Henrietta Rd and Ridge Rd E.

At $4.29/gallon it ain't cheap. I just put 2.917 gallons on top of what I'd estimate at about 10 gallons of 93 Sunoco already in the tank. Average that out and it's 94.6 octane. We'll see how she runs. I want to start lower for testing purposes... which brings me to a question:

What are you guys doing for a/f/boost controlling? I have nothing to adjust these factors with, so will running a higher octane gas simply allow the combustion cycle to complete with more efficiency at this point? Will the ECU compensate with timing advancement for a more complete burn? How far can the ECU adjust per octane increment? Should I just shut up and drive the thing?

 

Hey all a little update-

Car definitely pulled harder with the last tank of gas. Power seemed more linear to the redline for sure. 1st gear was where it was particularly noticeable, and 3rd when say merging on the highway and you're WOT.

FWIW I averaged 18.9mpg on 12 gallons of appx. 94.6 octane fuel. That happens to be my best yet and I definitely drove with a heavy foot 90% of the time. I'd guestimate about a 50/50 split highway/city with every highway merge being WOT to redline in at least 1 gear.

Just put in 4 gal @ 100 octane, and 8 gal @ 93 octane, raising me to average 95.3 octane for the tank (considering an estimated 1.5 gallons of 94.6 left in the tank at time of fill up). Calculation as follows:

((4gal * 100) + (8gal * 93) + (1.5gal * 94.6)) / 13.5gal = 95.25...

I probably shouldn't even be rounding to the nearest tenth, should just be sticking with whole numbers, but what the hell. It's still an estimated 1.0 points higher at 94 vs 95.

We'll see how she does on this tank!

BTW temps are averaging 35-50 degrees around here right now, light humidity.