Pre Ignition and Detonation / Pinging / Pinking / Knocking
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Physicists find way to control detonation wave in promising new type of engine
Skoltech researchers have theoretically predicted synchronization—a kind of self-regulation—in detonation waves. The discovery could help tame this inherently chaotic process so as to stabilize combustion in a rotating detonation engine. This refers to an experimental device potentially...
Various sources of load can also contribute to adverse ignition events. Be it the obvious things like a full compliment of passengers, towing, going up hills etc, or the not so obvious; AC on, dragging brake/s, altered gearing, significantly heavier wheels/tyres etc.
An alloy head (all things being equal) is considered to be capable of tolerating one full point of compression more (over the same head made out of cast iron), due to its greater heat dissipation/transferring ability. On the same token if your alloy headed car's cooling system is running hotter than it should it will be more susceptible to pre-ignition/detonation. Also the inlet air temperature can also have a significant effect so it pays to ensure any cold air piping and associated flaps/levers are in situ and functioning as designed.
One of my vehicles is running 10 to 1 static compression with 10 psi of boost via a Roots supercharger. Even with the Roots style blower's poor adiabatic efficiency I'm still able to run the vehicle (pre-ignition and detonation free) on 95 octane fuel. However, the car is extremely lightweight, has very low rotational masses, has an all aluminium engine, the cooling system runs at 160C and it has a very short cold air induction tract from the bonnet scoop to the carburettor. I run 15 degrees of lead at idle and a further 15 degrees of mechanical (at the crank) advance that is all in by 2500 rpm.
An alloy head (all things being equal) is considered to be capable of tolerating one full point of compression more (over the same head made out of cast iron), due to its greater heat dissipation/transferring ability. On the same token if your alloy headed car's cooling system is running hotter than it should it will be more susceptible to pre-ignition/detonation. Also the inlet air temperature can also have a significant effect so it pays to ensure any cold air piping and associated flaps/levers are in situ and functioning as designed.
One of my vehicles is running 10 to 1 static compression with 10 psi of boost via a Roots supercharger. Even with the Roots style blower's poor adiabatic efficiency I'm still able to run the vehicle (pre-ignition and detonation free) on 95 octane fuel. However, the car is extremely lightweight, has very low rotational masses, has an all aluminium engine, the cooling system runs at 160C and it has a very short cold air induction tract from the bonnet scoop to the carburettor. I run 15 degrees of lead at idle and a further 15 degrees of mechanical (at the crank) advance that is all in by 2500 rpm.