I decided I need some extra octane even when not in boost and need some advice. I read a little about toluene saying its 114 octane and can be mixed with gas to bring up the octane. I also found a local 76 station that sells 100 octane race fuel for $6 gal. The question is, in my research I found people saying a toluene gas mix would spool the turbo faster, has anyone heard this. I don't think I have ever been able to find it anyway but it might be fun. I am going to try to get 10 gals of 100 octane at lunch. Online vendors wanted up to $14 per gal for 100 plus shipping.

Even if I can run a 50/50 mix of race gas and 91 and bring it up to 95 range that would help out nicely. Heres a octane chart for the TL 91 octane mixed with 100 octane race gas
1 gal race/16 gal 91= 91.5
2 gal race/15 gal 91= 92
3 gal race/14 gal 91 = 92.5
4 gal race/13 gal 91 = 93.11
5 gal race/12 gal 91 = 93.6
6 gal race/11 gal 91 = 94.17
7 gal race/10 gal 91 = 94.7
8 gal race/9 gal 91 = 95.2
9 gal race/8 gal 91 = 95.7
10 gal race/7 gal 91 = 96.2
11 gal race/6 gal 91 = 96.8
12 gal race/5 gal 91 = 97.3
13 gal race/4 gal 91 = 97.8
14 gal race/3 gal 91 = 98.4
15 gal race/2 gal 91 = 98.94
16 gal race/1 gal 91 = 99.47
17 gal race/0 gal 91 = 100

 

I forgot there was a race forum where they would explain how to mix your own race fuel. There were certain ratios they followed with the mix. If I find that site I will try to pass the info out.

 

You may also want to check out 109 unleaded. It's more expensive but it may be cheaper mixing it at the same octane.

I would go with the race gas over tolulene. I've run a lot of tolulene and xylene and they're fine but with race gas you don't have to worry about running too strong of a mixture.

Tolulene won't make the turbo spool any different.

Race gas is usually formulated to burn a little quicker and optimized for racing. The 109 will supposedly mix better and evaporate quicker for a better cooling effect. There's not a big difference in the two but race gas will probably give a small edge in power.

FWIW, I believe xylene is 116-118 octane and about the same price as tolulene.

If you have a 100 octane station in town, that's the easy winner. It gets old getting out the funnel and mixing tolulene.

 

Update:
I picked up 10 gal of race 100 octane and 7 gal of 91. The car seems the same and I'm running 96.2 octane and turned the boost down to 6 psi in preparation for a retune.

 

Did you try it with the boost at it's normal level with the race gas before you turned it down?

 

It's still bleeding off boost to fast. I turned down the boost prior to getting the race gas. I'm not sure if the mixure made it to the injectors yet since I didn drive very far after filling up. I will get a better idea tomorrow after I put some miles on it.

On a slightly related note I'm pissed I still can't get the AEM FIC software to work. Car feels great out of boost, but once it goes into boost it doesn't pull like it should.
I have been working late and my tunner is only available at night so I haven't been able to go by. I'm also still trying to decide what octane I am going to tune for to keep the engine safe while not in boost but not be too rich of a race gas mix to save $$$.

 

Didn't Rodney send you out a totally different F/IC? Are you using the same computer to try and connect? If you are, then it's likely your computer.

Mine works flawlessly. I even tried some quick logging and that works as well for what it provides.

 

Rodney did send me another Fic but I haven't put it in yet. He wanted to walk me thru a few steps before I plug it in. My plan was to have the tuner install it and retune my car but it's hard to find the time. I'm in the process of buying a boost controller and getting it and my meth injection installed.
With the higher octane gas I feel more comfortable running a more aggressive timming map. I bought race gas by the can for awhile at $12 per gal, when this gas station was a mile or two away and selling it for $6 per gal.

 

Sucks you don't have 93 octane in California. How's the $3.50 per gallon treating you?

 

After $6 a gal gas a few years ago $3.50 is great.

 

Update:
I picked up 10 gal of race 100 octane and 7 gal of 91. The car seems the same and I'm running 96.2 octane and turned the boost down to 6 psi in preparation for a retune.

 

i just paid $2.70 for 93 today i love Texas

 

I used to run 110 leaded in my old STi for the race map. Leaded fuel is badass, aside from the fact that it's terrible for the environment and you can't run it if you still have any catalytic converters :P

 

more info on leaded fuel

 

I've put about 100,000 miles on leaded gas.

You can't run it with 02s and you can't run it with convertors. Typical heated 02 sensors will last a few tanks of gas with automotive unleaded. Mine lasted about one tank with 100LL aviation fuel.

For pure performance I love leaded race gas. At the time I quite running it, it was quite a bit cheaper for the octane rating than unleaded was. The lead is good for exhaust valves and seats. Lead is a super cheap octane booster.

My car seemed to be less prone to detonation on leaded gas of the same octane.

I highly discourage the use of 100LL av gas in a car or at least in a full mixture. My GN could originally run 16psi boost on 91 and 24psi on av gas. It typically ran about $1 more than 91 so I ran it full time including long trips. As time went on I could run less and less boost without running into detonation. Toward the end (about 1.5 years) I could only run 10psi on av gas and I didn't even bother to find out how low it would be on 91.

I went nuts trying to diagnose it. After I shattered the axle I pulled the heads off (which is how it sits today) and found more lead build up than I thought possible. The pistons have 1/4" caked on as did the heads and you could see where the piston deposits had hit the head deposits. It was probably running 13:1 compression from the original 8.5:1.

100LL has 8 times more lead than automotive race gas. I did not know that at the time and I figured since it has the "low lead" designation it probably had less lead than auto fuels. So I paid the price for being cheap.

This stuff would be a very cheap octane booster in a 50% mixture. It acts as if it has more octane than 100 unleaded. I never verified it but it acts like it has a slower burn rate than pump or race gas. I had to add 4 degrees more timing to make up for the initial power loss.

But back on topic, run the automotive leaded race gas (VP 114 is awesome with it's quick burn rate) if you have no 02 sensors (or a replacement on hand) and no convertors. I've found the Denso sensors to be very tolerant of lead. No one seems to know why but toward the end when I still ran a stockish 02 I only had half a year on the Denso but it never failed.

Sorry, I know this post is all over the place but I'm in a big hurry. I'll clean it up later.

 

IHC pretty much summed it up as usual

Leaded fuel gives a much higher margin of safety against detonation over unleaded. You can crank up the boost. As a frame of reference, with a good dyno tune I gained over 110whp/110wtq by switching from the 93 octane map to 110 leaded.

Here are the old dyno charts I found in my photobucket:

93 pump gas:


VP 110 Leaded: