Toluene?

degreeoff1 · 03-31-2008, 06:48 AM

OK before you tell me to seach....I have with few direct responses to the "T" factor...I am running carbs with NEW SS fuel lines (rubber lined) AN stuff. Will it be cheap insurance against detonation?

Formerly Steve Wilkinson · 03-31-2008, 07:04 AM

There are searches and there are searches. Google "toluene octane" and you'll get a ton of responses from people using it.

Porsche-O-Phile · Porsche-O-Phile's Garage

I'm not certain how the lines will hold up to it but toluene/xylene blends are a trick among 951 tuning guys to run higher boost levels. I think some of the guys run up to 25% blends. I never ran higher than about 3 gallons in a full tank (+/- 13%) and got great results all the way up to 22 psi.

Porsche-O-Phile · Porsche-O-Phile's Garage

I'm not certain how the lines will hold up to it but toluene/xylene blends are a trick among 951 tuning guys to run higher boost levels. I think some of the guys run up to 25% blends. I never ran higher than about 3 gallons in a full tank (+/- 13%) and got great results all the way up to 22 psi.

cashflyer · 03-31-2008, 07:38 AM

http://www.elektro.com/~audi/audi/toluene.html

degreeoff1 · 03-31-2008, 08:01 AM

I have done those seaches, I guess what I was after was a little first hand porsche 911 experience.

Zeke · 03-31-2008, 08:29 AM

I have some first hand air cooled experience as I used a head temp and exhaust temp gauge setup on my kart and used a bit of toluene. It runs hotter.

RarlyL8 · RarlyL8's Garage

The vapor pressure of toluene is much less than that of ethanol, for example. Both increase octane rating but toluene will run more hot while EtOH runs cooler.
Be conservative with your blending and watch the head temps.

degreeoff1 · 03-31-2008, 09:53 AM

Well I would like to run 10% as a starter. Just wanted to make sure I could. I will run race gas @ tracks or at least a 50/50 there but for spirited street driving my 2.7 9.8:1 pistons with single plug heads might need a wee bit more that 93 Oct.

jluetjen · jluetjen's Garage

What sort of cams are you running? If you've got something like S cams, 9.8:1 on super is most likely not such a big deal. I used Toluene for a while in my 2.0 with S pistons and E cams (and the result high-CR poor combustion chamber design) and it certainly helped reduce the pinging (and I assume detonation). But it's not like gas isn't expensive enough, and it got to be a drag constantly mixing the stuff. You can't just dump it in the tank like octain booster. It doesn't mix that well with gas, and if you're depending on it to keep the detonation down, you need to be fairly consistent with the mixture. So now that means you're mixing it in external tanks and shaking it up in order to ensure that you get a good mixture.

At the end of the day I ended up retarding my ignition timing some and going back to straight high-octain and my engine has been happy ever since.