Is there a basic formula to figure size requirements? Any help would be appreciated. Thanks Guys
Chad
Help with sheet metal plenium size
Moderator: Team
It depends on RPM and the number of cylinders drawing from the plenum, but there's a good article in the February '06 Popular Hot Rodding on fabricated manifolds, and one of the builders they interview, John Beck www.beckmechanical.com , says it should be about the same volume as the engine; smaller improves torque, larger improves high RPM power.
David Vizard, in his How to Build Horsepower Vol 2. says the plenum doesn't really work as a Helmholtz resonator with more than 4 cylinders connected, but gives numbers for 2, 3 & 4 cylinders (e.g. 2 for a V-8 ) as around 100%, 65-80% and 50 -60% engine volume respectively.
David Vizard, in his How to Build Horsepower Vol 2. says the plenum doesn't really work as a Helmholtz resonator with more than 4 cylinders connected, but gives numbers for 2, 3 & 4 cylinders (e.g. 2 for a V-8 ) as around 100%, 65-80% and 50 -60% engine volume respectively.
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.