Heretic

Mixing old school simplicity with new school performance. Heres how she looks on her first day at her new home The wheels are for sale on trademe by the way

Why run low compression in a turbo motor? To fit more fuel in, plain and simple. High compression motors can run turbo's, but you can't fit as much fuel in without having reliability issues. From memory, Ronnie Lim was running something like 7.5:1 compression with 40psi boost, or some crazy combination like that - you'll make a bit more power and be reliable, but you'll get really crap fuel economy. As for the octane, thats a safety thing - the higher the octane, the less likely detonation/pre-ignition will be. Thats not to say that 98 will make your 1.3 corolla run any better than 96, since its probably not got the intake system to make detonation/pre-ignition a problem, but with a turbo vehicle, this can make the difference between reliablilty and detonating itself to bits! Also, theres a common misuse of the word detonation - detonation is not so bad, as its not that destructive, but the one you want to avoid is pre-ignition, which is when the air/fuel mixture is compressed to a point where the mixture gets too hot and ignites itself without a spark. This is not necesarily bad, as this is how a diesel engine works (in principle, except the diesel is added to the already compressed air to ignite the mixture), but with a petrol motor, this usually happens when the piston is still in its compression stroke, so the piston is pushing against the expanding ignited fuel (very very bad!) http://www.streetrodstuff.com/Articles/ ... /index.php