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Old 01-05-2011, 08:01 AM   #1
The Radium King
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Join Date: Apr 2010
Location: Canada
Posts: 3,121
exhaust / cutouts / variocam

hi folks, got a question. in all the reviews i've read, dynos i've seen, etc., i've come to the understanding that the stock porsche exhaust is tuned (unequal pipes, specific back pressure) for low rpm power (better driveability). most aftermarket exhausts (equal pipes, less restriction) are tuned for high rpm power (big hp #s sell cars, but dynos all show power LOSS in the 2500 rpm area).

i also note that the stock intake is designed for both low and high rpm power - the variocam switches over, as well the resonance flappers on the intake manifold and plenum, as rpm climbs. the control of these is a combination of vacuum and ecu/rpm.

would it be possible to design an exhaust cutout that was either ecu/rpm or vacuum controlled that would drop the second cats and mufflers and go to straight pipes at the same time that the intake switched over to 'high rpm' mode? would it be as simple as using the same vacuum lines that drive the intake resonance flappers to drive a vacuum-operated exhaust cutout valve?

that way no need for expensive mufflers, midpipes, headers; just a cut-out that installs between the headers and the mid-pipe?

Last edited by The Radium King; 01-05-2011 at 12:00 PM.
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