Quote:

...what if we just test the port without adjusting the test pressure?This should very closely simulate the flow of each lift of the valve at the same engine speed...



I don't think so. If you've even seen graphically the pressure variations that an engine experiences in the intake & exhaust tracts as it runs through the complete 4-cycle series, you'd see there's a whole lot more going on there.

Unfortunately, using the same standard test pressure for each lift is the simplest way to capture comparative data from one head / port to another. Does it accurately reflect exactly what's going on with a running engine? Not really...

EDIT: Go check out http://www.audietech.com and look at the page for the Dynomation 4 Stroke program. Scroll down to see the "pressure graph screen" showing intake & exhaust port velocities vs. crankshaft rotation to get an idea of what I'm referring to.

Last edited by Brad_Hawk; 02/22/05 07:01 PM.