How does the intake manifold "work"
Thread Starter
Teching In
Joined: Dec 2005
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How does the intake manifold "work" I've been seeing this cross-over type intake plenum on more and more vehicles. Is it a dual stage plenum? If I could just see a cross-sectional view of it, I think I'd understand how it functions. I don't have a vehicle with this intake myself, otherwise I could have taken it apart.
thanks
Pete
thanks
Pete
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If you mean the "tork link" (I think that's the name), aftermarket carburettor manifold, I believe the runners are crossed over to allow increased length, tuned for mid-range power, without turning the manifold into a hood-piercing tunnel ram. (Or are you speaking of OEM EFI systems?)
Thread Starter
Teching In
Joined: Dec 2005
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The OEM plenum.
I found a cross section view here...
http://www.idavette.net/hib/ls6/imag...es/407B_12.jpg
It doesn't appear to be 2 stage or anything. Are the runner lengths tuned to a specific rpm?
I found a cross section view here...
http://www.idavette.net/hib/ls6/imag...es/407B_12.jpg
It doesn't appear to be 2 stage or anything. Are the runner lengths tuned to a specific rpm?
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Yes they are. There's actually several RPMs that a given length will 'tune' to (not necessarily more than one in a particular engine's operating range). Packaging, the gap between tuned RPMs and other considerations weigh into the mfgrs. design. Also the plenum volume can have a separate "Helmholtz resonance" tuning effect. BTW, tuned lengths have been used for 80 years or more. I've seen test data from the thirties...
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Runner length versus torque. Best OEM example, I can think of, is the TPI (Tuned Port) system with it's long runners and mucho torque. There is an excellent, simplistic (that I could understand 
) explanation in John Lingenfelters SBC Performance book. FWIW.
) explanation in John Lingenfelters SBC Performance book. FWIW. 
