[PFM]

Some more input to compression and knock.

Below is a quote from David Redszus, a racing engineer. Clearly he is describing the 3.6 piston. The underline I provided. Makes you want to look a little harder at some of the aftermarket pistons.


True hemi chambers have a real problem with compression ratio and squish velocity. The resulting combustion chamber shape does not lend itself very well to flame front travel and is often quenched on contact with a chamber or piston surface.


The best solution I have seen was a design by Porsche. They used a full dome piston nested closely against the chamber wall to provide a high squish velocity. The actual combustion chamber was actually a bowl cut into the top of the piston. This combination produce extraordinary high flame speeds, and a compact chamber to prevent detonation. I could see where they could run very high turbo boost pressures and still prevent detonation.

Regards,

PFM