Posted by keith on November 20, 1999 at 23:43:05:
In Reply to: Performance Boost posted by Witch Doctor on October 25, 1999 at 01:22:13:
I am glad you pointed out the misconceptions about high octane gas, that it can reduce power is news to me but it does make sense. Here's some information for you. The phenomenon you are discussing is not pre-ignition. It is detonation.
from the Airframe and Powerplant Mechanics General Handbook, when detonation occurs, the first portion of the carge burns in a normal manner but the last portion burns almost instantaneosly, creation an excessive momentary pressure imbalance in the combustion chamber. Preignition is caused by hot spots or surfaces in the chamber igniting the fuel-air mixture. It this happens before the spark plugs get the chance to do their thing, it's called preignition (The Advanced Pilot's Flight manual).