Root of all Evil

I have a time attack build, it made 450whp on 94 with a spoolin log on a dynojet. I'm going to be increasing the power this year with a larger turbo (silversurfer) and I'm looking at a Meth kit vs just running race gas. With Meth I know you get a cooling effect and lower egts but what is the cooling effect of adding slightly more fuel with 110oct? I can get race gas pretty easy so that's not a concern, what is going to benefit me most? One aspect of racegas I like is it can't fail like a meth system but obviously it's very expensive especially in Canada. I'm running s300 v2 btw.

TheShodan

iTrader: (14)

Well, this isn't a "vs" argument, really. Both perform the same job, albeit in different ways. They both have knock resistant properties to prevent detonation by allowing you to run lower Air-Fuel-ratios so that you can run higher boost pressures to make more power. The cooling effect of methanol / water is from the water portion of the mixture that creates a steaming mist effect that cleans carbon deposits and such within high cylinder pressure situations found in turbocharging (which is why you don't see people running NA using it.)

Race fuel also has knock resistant properties that work to its advantage. Because of its chemical properties (including toluene) that allow it to create higher BTUs than 93 octane or even E85, you can also run higher boost pressures at lower injector duty cycles.

This is a matter of preference. For Time Attack, you can run either one, however, using methanol on some tracks may require you to run the tank either in the engine bay, or have a separate tank that is foam filled (NOT the one included in the AEM Meth/water kit) in order to run it from the back.

If this is more street than attack, methanol is a nice viable option. If simply time attack only, you're not driving it enough to worry about the cost as much... continue to run race fuel.

Its preferential at this point.

wantboost

iTrader: (2)

Race gas is more detonation suppression since it's a higher octane fuel. If it's a petroleum based fuel and not an alcohol based fuel then it's cooling properties will be equal to that of standard pump gasoline. The detonation suppression comes from oxygenating and leading the fuel on top of increased octane and other chemical additives.

The main benefit of methanol/water injection is the cooling effect however tests have shown that injecting 100% water cools the intake charge equally or better than a 50/50 mix of methanol and water. We did some tests around Atlanta Motorsports Park with a built Lotus Exige S and we got the same results comparing 50/50 to straight water. The addition of methanol is to increase the detonation threshold through increasing octane. I don't remember the amount it increases with a 50/50 mix but it's based mainly on injection rate which is around 1cc-2cc per BHP. To reach race gas levels you'd have to inject a fair amount of 50/50 or step up to something like a 70/30 methanol to water ratio. Also either snow or devils own has shown adding small amounts of nitromethane to yield excellent results and sells small bottles for that purpose.

Aquamist has excellent articles on injection and IMO is the leading company, they were among the first if not the first to start offering kits and using digital controllers. I'll be using their kits on my builds, you gave total control over every aspect including built in failsafe measures (doesn't require an external unit like aem). I'll post the articles and such when I get home here soon.