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      11-14-2019, 06:00 PM   #161
spool twice
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Drives: BMW M4cs
Join Date: Sep 2010
Location: Tampa Bay, FL Area

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2019 M4cs  [0.00]
For sure, someone made measurements in another thread where a few of us are trying to equalize the natural even firing exhaust pulses in another thread (with success too!)

Somewhere in there was measurements of pipe diameter between both banks to possibly slow down the velocity of the pulses on one bank in an attempt to equalize the spaces once they crossover. That's really the key to getting a different sound character to the S55:

Here is my recent clip of my exhaust mod:
-stock downpipes
-stock midpipes
-center resonator/crossover delete
-custom equal-length exhaust pipes
-crossover x-pipe (previously was an h-pipe)
-stock muffler

It's basically this where the red lines represent new pipes, and the crossover now occurs behind the rear differential (the drawing is terrible I know, but its basically that...)





and a revving comparison between stock ZCP, ZCP w/ aftermarket single midpipe and secondary cat delete, and a set-up with equal-length exhaust pipes and chambered crossover section


Last edited by spool twice; 11-22-2019 at 01:22 PM..
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