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911nut 911nut is offline
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Join Date: May 2001
Location: Michigan
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Originally Posted by Speedy Squirrel View Post
For scavenging to work you need to have a fairly large amount of overlap in the valve events. The idea is that a low pressure suction pulse will travel back up the tube and arrive at the exhaust valve just as the piston has gone past TDC and is started on the intake stroke. The low pressure pulse will still let exhaust gas flow out of the engine, even though the piston is now going down. Obviously, such a situation can occur only at a very narrow RPM, and needs a cam with a lot of overlap to work really well. If you are like most, you have the classic turbo cam, which has exceptionally low overlap, so forget about scavenging.
Sounds like all of this back and forth about equal length vs. short path is moot then. It also saves me $2500
Paul B.
'91 964 Turbo
Port matched, SC cams, K27/K29 turbo, Roush Performance custom headers w/Tial MV-S dual wastegates, Rarlyl8 muffler, LWFW, GT2 clutch & PP, BL wur, factory RS shifter, RS mounts, FVD timing mod, Big Reds, - 210 lb
Old 01-17-2010, 11:25 AM
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