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Jim2 Jim2 is offline
7.0:1 > 11.3:1
 
Join Date: Oct 2003
Location: Calgary
Posts: 1,680
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F1 car 19,000 rpm: 2.5" intake runners

Buick V6 FWD automatic 2500 rpm: 17" intake runners



Porsche V-ram and non V-ram have the same peak HP, but he V-ram has more mid range torque resulting from Porsche adding intake runner length as seen on the top of the intake manifold.


Overview: Exceeding 100% volumetric efficiency on a reciprocating internal combustion engine requires "pulse" tuning, among othere things. This "pulse" occurs when the moving column of intake charge is stopped by the intake valve upon it's closing, the moving charge column bounces off the back side of the intake valve and reverts the othere direction up the intake runner leaving a region of low pressure behind itself. At an optimal intake runner length the reversion wave goes right out the end of the velocity stack, at which point the differential pressure drives new charge back down the velocity stack. If the intake valve is open when the reversion wave arrives theree is an opportunity to impact the cylinder with charge exceeding atmospheric pressure. There is really lots of stuff going on, more than meets the eye. A 930 intake would be suited for an RPM well beyond the engines mechanical limit, except that there IS NO PLENUM eithere...
Old 02-06-2007, 09:50 AM
  Pelican Parts Technical Article Directory    Reply With Quote #20 (permalink)