Darren Mayer answers your questions about supercharging


I have what might be thought to be a big quench area with a polished chamber. What would be an appropriate quench for my application? It has Chrysler 346 open chamber heads, 0.010 quench on the head, 0.040 copper gasket, 0.060 deck height, "69"440 cu. in, 0.9.5 cr. Isky, 0.555int., 0.575 exh.8-71 blower, 8 lbs of boost, o ring block, 2x850 carbs holley's, msd 6al,34 deg @2500 rpm, automatic 4k converter, 3.73gears, 30" tire, 4000 lb. car. Your input is greatly appreciated! I love the web page!


The quench area is the portion of the cylinder head that is opposite to the chamber. The quench is flat; the piston approaches the quench area quickly as it passes TDC. The quench is important in naturally aspirated engines as the high- velocity gasses pushed back into the chamber from the quickly approaching piston help with homogenization of the air/fuel mixture. Super stock and comp eliminator guys have known the value of a tight quench area for years. However, with your blown application, the quench is not as important. The increased volume of gasses reduce the importance of a tight quench area and in the blown alcohol category many engine builders believe that the quench actually hurts power because it is believed at high rpm the large quantity of gasses can't accelerate towards the chamber fast enough and cause an increased power draw to rotate the engine at rpm.

Looking at your numbers, you're telling me you have 0.100" of quench clearance. That is a large amount for an aspirated engine, but your blower engine will not know the difference. The blown gas engine is best with low compression, as you have indicated.

Darren Mayer




To contact Darren Mayer write


Previous Stories
Super Charged Science — 1/8/04


Cover | Table of Contents | DROstore | Classifieds | Archive | Contact
Copyright 1999-2003, Drag Racing Online and Racing Net Source