Hey im just a newbie..and im asking why is it that if you run your engine with a higher octane that you can prevent your engine from detonation and boost your turbo to 20+ psi?

 

higher octane has better quality and less unnecessary particles to burn off.

 

when you raise your boost, you raise the effective compression ratio of the combustion chamber by forcing already compressed air and fuel mixture into the cylinder.. the Octane in a fuel keeps the mixture from "Flashing" when compressed (preignition or detonation) the additives (octane boosting compounds) more or less slow the burn rate of the fuel and raises the flash point which gives the fuel the opportunity to be compressed and ignited by the spark plug..

Detonation happens prior to the piston hitting top dead center (the highest point of the piston where compression is highest) and the effect is the gasses (And shockwave caused by the gasses exploding) are acting against the piston by trying to expand while the piston is continuing to try to compress.. Ultimately if it happens often enough, it has to go somewhere, and it will be the weakest point on the engine, or some other flaw such as a microscopic crack.. much of the time the heat and gasses can eventually burn or crack the piston..

Other failures can occur, Head bolts stretching, valves burning, crank failure, block cracks, even turbo damage due to a backfire..

I tried to keep this explanation simple and academic and as accurate as I can recall.. Feel free to correct anything I might have stated as innacurate..

 

thanks. Very informative for a newbie like me.

I could'nt understand why detonation would cause a lot of damage prior to your post.

Now a couple of questions:

1) How can you monitor if your damn close to detonation?
2) Besdies higher octane gas, How can it be avoided?
3) People say that buying an ecu would be a safe way to up the boost. Why? A performance chip as i understand, has a different table mapping for Air-fuel mixture, avoiding a lean mixture with a higher boost. Why would a lean mixture be more susceptible to detonation?
4) Granted you have a performance chip, would it be safe to increase boost without upgrading fuel?

thanks

 

1) Get a wideband O2 sensor and an exhaust gas temperature. Back off when EGT gets too high.

2a) Lower the intake charge temperature by installing a more efficient intercooler, sitting on the intercooler spray, migrating to Canada etc.
2b) Water-injection (jury's out on this, experts are divided etc)
2c) Avoid high RPMs

3) Higher fuel content will lower the intake charge temperature slightly.

4) Depends on your tolerance for risk exposure.