Quench Explanation

You're centralizing the burn/mix around the plug/valves, squishing it toward with force getting a more faster complete burn.jmo

KB pistons says...

A single side tight quench is a very important combustion enhancer that an engine builder can use to speed flame travel. What quench does that doesn't happen with high swirl or tumble chambers is TDC drive. A normal ignition system starts a small flame about 30° before TDC that burns relatively slow. The piston stops just short of hitting the cylinder head, a blast of air is forced from the quench area through the previously lit flame front. The flame front is driven through the chamber, increasing the chamber burn rate sufficiently to build maximum cylinder pressure early after TDC. The old way to get maximum cylinder pressure early was simply to run 40° of timing. The problem with the old way is that a long slow burn is more affected by hot spots, fuel distribution, spark scatter, chamber temperature, and general cylinder-to-cylinder variation. Don't forget the negative torque component of 40°.