Quote:
Originally Posted by cmcfaul
Does more overlap = greater VE (Volumetric Efficiency)?
Chris
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It means more VE at a particular, narrow, high rpm band. It will be because the air has enough momentum to keep coming in through the open exhaust valve even though the piston is coming up. The air only has that high velocity with ram air, velocity stacks, and a fast piston downstroke, or turbocharger pressure. The fast piston downstroke also means a fast piston upstroke, so there is a point where overlap is too much. Below that, there is more reversion so less VE. There are particular harmonics- bad and good ones, like a tuned exhaust system. Everything needs to work together. Cams, intake, timing, exhaust.
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1971 911S, 2.7RS spec MFI engine, suspension mods, lightened
Suspension by Rebel Racing, Serviced by TLG Auto, Brakes by PMB Performance
Last edited by Flieger; 11-05-2010 at 11:16 AM..
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