Originally Posted by HDDP
Save your money and make it yourself for track days. We call this "Rocket Fuel".
These are based on LA prices
10 gallons of 91 octane @ $3.45
1 gallon of Toluene, 115 octane @ $6.50
1 gallon of Xylene, 112 octane @ $6.50
1 gallon of Klotz Coxoc, oxygenator @ $22.00
Final octane level is somewhere in the range of 102 and only costs you $5.34 a gallon.
With an OEM ECU, you run the risk of the timing being retarded to offset the fuel, but it works great with ECU maps that advance the timing. Especially good for forced induction engines.
Apart from the fact that its not available near me, I wasn't seriously going to try it. There really is no point when the stock motor is mapped to run on 95 octane. Like you say it's the forced induction guys who will really benefit.
I'll file that recipe away though for when I start looking at engine mods. I think the full race M3 that was out on the track last weekend was running something other than plain 95, my eyes were watering when I caught a blast of the exhaust in the paddock!