Originally Posted by I hate cars

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.

Originally Posted by I hate cars

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.

Originally Posted by WRXtranceformed

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:

Originally Posted by ihatecars

I agree with your posts.

I did some knock monitoring in the middle of a hot summer and the TL knocks badly in stock form in high temps. I tried different mixtures of 91 and 109 and it took around 96 octane to completely get rid of the knock.

So the answer is to use the highest available octane for the TL. Octane boosters usually have toluene as their octane booster but you can but this stuff at the paint store in a gallon container for about the same price as the 8 ounce container in the autoparts store. The little bottle they sell won't boost it more than a few points at best. 91 to 91.3
octane.

You will see gains of mpg and hp until you get past the point of knock. How much of a gain depends on the severity. You might see a few lbs of torque on the dyno and mpg change would be there.

In a hot summer mine pulls so much smoother and without the initial hesitation from the ECU pulling timing and trying to put it back in constantly. My mpg went way up in city driving but mine was pretty bad without the extra octane.

To the OP, I just wrote nearly this exact thing in another octane thread last night and I have several much more detailed threads on octane out there that you can find with a search.

Originally Posted by Bwatson3

what ratio do you mix the toluene..and do you add it to hi octane gas from the pump..?

Originally Posted by I hate cars

No more than 30% for fuel system safety or whatever mixture it takes to get rid of the detonation.

Originally Posted by Bwatson3

more like how much tolulene would you add to a full 15 to 17 gal fill up. .? And do you add it to regular 87 octane or do you add it to the highest available at the pump..? Im not very good with the 30% thing..math was never my forte..

Originally Posted by phee

your gas light comes on when you have a 3 gallon reserve out of your 17 gallon tank

17-3=14 gallons

30 percent of 14 gallons is 4.2 gallons of toulene

percentages are calculated in this manner

14 (# of total gallons) * (times) .30 (decimal in front of percentage) = 4.2 (the amount of the percentage out of the total)

if you have a smaller percentage, say, 3% you would add a zero after the decimal like this - 14 X .03 = .42 gallons (half a gallon)

Originally Posted by I hate cars

If you want a 3% mix do half a gallon.

You have to count the reserve capacity also.

Just make it easy. Run it down to the light, put 7 gallons fuel then add 3 gallons of toluene. The second time, do 10 gallons of fuel and 3 gallons of toluene.

30% will give approx 96.7 octane.

It's more cost effective to run 100 or 109 unleaded fuel in a mix.

Originally Posted by HEAVY_RL

Will it work? Yes, the only problem is I have heard of some brands "varnishing" components with prolonged use.

The real question is how old is that fuel and how clean is it? Farm trucks are a lot more tolerant that our cars.