I want more power and the engine is detonating! Do I need an adjustable fuel pressure regulator to run richer to eliminate the knock?
Maybe. It’s somewhat true that running a tad bit richer will help quench detonation (knock), but only to a certain extent. The stochiometric AF ratio for gasoline is 14.7:1. Stochiometric means that at this point, the fuel is completely burned with no unburned hydrocarbons left, giving you best emissions. This is the AF ratio the PCM is shooting for under idle and cruise.However, best power is achieved for gasoline at around 12.5:1, leaving excess unburned hydrocarbons, but no unused oxygen molecules! (This is why 12.5:1 is typically the best power point.) So under ideal circumstances, the best power AF ratio to shoot for is around 12:1 to 12.5:1. However, running a tad bit richer will throw excess fuel (gasoline) into the combustion chamber, and the extra unburnt fuel actually acts as a heat sink, absorbing heat and cooling the combustion temperature, hence reducing the tendency for detonation to develop. However, this only helps to a certain extent. If you’re knocking severely, you c
