CA 91 octane gas sucks -- trying Xylene

[MRC01]

Based on a recent dyno run of my car, it's lost almost 10 HP since California went to 91 octane ethanol based gas (same car, same dyno, both SAE corrected).

The engine ('98 Cobra V-8 in a Panoz Roadster) is designed to burn non-oxygenated 92 octane fuel. The recent dyno run showed light detonation and the computer compensating with timing retard. I got 280 RWHP on the old 92 octane gas, and just recently dynoed again and got 271 RWHP. That's same car, same dyno, both numbers SAE corrected at the rear wheels.

My choice would be Toluene or Xylene. But Home Depot doesn't sell Toluene anymore. Seems it's used illegally for meth labs so a lot of places stopped selling it. So I bought a gallon of Xylene to try it out. Assuming Xylene's (R+M)/2 octane is 116, I get:

10.5 gallons 91 + 0.5 gallon Xylene = 92.1 octane

I don't want to go over 92, since the engine doesn't need it and won't use it.

I searched and found some threads on this subject but no definitive word whether Xylene in a roughly 1:20 ratio will hurt anything. I don't think so, since pump gas already has Xylene in it, so adding 5% more doesn't seem like it would hurt anything.

I'll report any differences I observe. How many of you guys with high performance cars suffering from California's 91 octane gas have tried this?

Also, is the Xylene you buy in the 1 gallon cans pure Xylene? Or is it mixed with other stuff (and thus unsafe for the engine)?

Thanks,

 

[Alex D]

Before I put such destructive stuff into my fuel system, I'd give Fuel Power a try and see if it doesn't fix this problem ....... I'd bet it will.

I can't even imagine what a healthy dose of Toluene or Xylene will do to injectors, regulator, pump and other parts of the fuel system. makes me shiver .......

 

[MRC01]

quote:

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Originally posted by Alex D:
Before I put such destructive stuff into my fuel system, I'd give Fuel Power a try and see if it doesn't fix this problem ....... I'd bet it will.

I can't even imagine what a healthy dose of Toluene or Xylene will do to injectors, regulator, pump and other parts of the fuel system. makes me shiver .......

---

From what I read, Xylene and Toluene are already in pump gas. If that's true, adding a small amount more shouldn't harm anything... all that is needed is 1 part in 20 to go from 91 to 92 octane.

Well I did it today, I could feel the engine kick a little better from 4,000 RPM on up at wide open throttle. That's where the knock detector was kicking in on the dyno runs. I've dynoed this car a few times so I know what it feels like and I don't think the butt-dyno is fooling me.

So far, no problems and no check engine light...

 

[M_Minnick]

I've used Xylene in concentrations as high as 2 gallons added to 3 gallons of 91 octane pump gas. I only do this at the track when running nitrous, and I usually mix in a little Marvel Mystery Oil for some added lubrication. Since it is one of the main ingredients in race gas, I feel comfortable using it and don't have to worry about fouling my O2 sensors as it contains no lead.

Mike

'99 Firebird
11.75 @ 120

 

[Ferb]

MRC, curious, but where what the 280 hp dyno taken? high altitude or something that needs correction?

ferb!

 

[MolaKule]

MRC01,

What you want is 4-Nitro-m-xylene, 99% or 2,4-Dimethylnitrobenzene.

Paint thinner etc are watered down wanna be's.

 

[MRC01]

quote:

---

Originally posted by Ferb:
MRC, curious, but where what the 280 hp dyno taken? high altitude or something that needs correction?

ferb!

---

Both HP numbers are taken at the rear wheels on the same Dynojet and SAE corrected. The actual measurements were at sea level, but it doesn't matter since they were SAE corrected.

The engine is rated at 305 BHP so one would expect 255-260 at the rear wheels SAE corrected. Conversely, the 280 SAE I was measuring at the rear wheels is 329 BHP. The 271 I'm getting now is roughly is 319 BHP. The increase over the factory rating is due to headers, underdriven pulleys, intake and exhaust. So the engine is healthy & strong, but it still can't make full power on CA gasoline.

Mol, thanks for the info. I'm using stuff marked as "100% pure Xylene" but that means more to you than it does to me. It does eliminate the pinging, though.

 

[Chumley]

Alex D writes:

"Before I put such destructive stuff into my fuel system, I'd give Fuel Power a try and see if it doesn't fix this problem ....... I'd bet it will.

I can't even imagine what a healthy dose of Toluene or Xylene will do to injectors, regulator, pump and other parts of the fuel system. makes me shiver ......."

Relax Alex! Then find a warm place and read these links:

http://www.atsdr.cdc.gov/toxpro2.html

see the sections on automotive gasoline, toluene, and xylenes.

Then see this link:

http://blizzard.rwic.und.edu/~nordlie/cars/gasoline.html

see section 4.13

Xylene is an excellent choice for octane building since that's one of the ingredients that the manufacturers use to build the octane rating in their gasolines! Just don't use too much because it will dilute the existing additive package, lower the vapor pressure, and may lead to hard cold starts if you live in a cold climate!

Chumley (adds both toluene and xylene all the time without issue)