Exhaust collector venturi function/advantage ??
Exhaust collector venturi function/advantage ??
(OP)
Just wondering if anyone could shed some light on the advantages of having a venturi type reduction/expansion incorprated into the design of an exhaust collector, eg:
[img]http://i21.ebayimg.com/01/i/08/37/6c/76_1.JPG[/img]
secondarily, what should the subsequent exhasut pipe look like? ie, if the collector reduces to 3", then expands to 3.5", should the exhast then taper back to 3" thus generating a chamber, or should things remain at 3.5"
finally, does this venturi type of collector effect the calculated harmonic length of the primaries which feed the collector?
cheers
ed
[img]http://i21.ebayimg.com/01/i/08/37/6c/76_1.JPG[/img]
secondarily, what should the subsequent exhasut pipe look like? ie, if the collector reduces to 3", then expands to 3.5", should the exhast then taper back to 3" thus generating a chamber, or should things remain at 3.5"
finally, does this venturi type of collector effect the calculated harmonic length of the primaries which feed the collector?
cheers
ed





RE: Exhaust collector venturi function/advantage ??
pulsing in primary pipes allows for improved exhaust scavenging of the combustion chamber at TDC overlap, but steady state flow in the tailpipe reduces back pressure.
Regards
eng-tips, by professional engineers for professional engineers
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RE: Exhaust collector venturi function/advantage ??
I'm sure that in practice the benefit of a smooth transition is of greater significance.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Exhaust collector venturi function/advantage ??
so im guessing that the 'bottle neck' in the collector at the point where the primaries merge is simply a consequence of the angle (and size) at which the primaries were collected? with the subsequent re-expasnion from this 'bottle neck' to x final dia then just a consequence of an expansion to the desired exhaust size over a gradual transition?
i was perhaps over thinking the design. i thought that the primaries were brought together deliberately tight, with a subsequent collector expansion as some kind of active feature of the collector. ie that the venturi shape was a design feature, rather than a design consequence
RE: Exhaust collector venturi function/advantage ??
burns stainless makes some nice ones.
Joe
RE: Exhaust collector venturi function/advantage ??
As opposed to having the across the collector from each other.