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      03-17-2015, 08:23 AM   #3
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Drives: Built not Bought 04 Z4 VF
Join Date: Feb 2013
Location: Kitchener Ontario Canada

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Quote:
Originally Posted by pokeybritches View Post
I'm fairly certain the rectangular section is a resonator. When I swapped in aftermarket catless headers, you could really smell the unburned fuel. The car smelled like it was catless. Since then I've added tiny Magnaflow cats (too small to fool the ECU), and the fumes are reduced by about 80-90%.

If you ever want to pass OBD2 readiness, the rectangular section is about the only place you can add cats large enough to pass emissions without sacrificing ground clearance.
Josh ya not sure why I wrote secondary cats, I know non M's don't have them.
As you know I put dual cats in the area where the resonator is on my custom exhaust(sold btw)
I am going to try the simulator approach on this one.
I picked up an oem exhaust at the local yard for peanuts to experiment with.
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W2A Intercooled Vortech V3Si, custom ducting, Alpha N, 60# Bosch,2.62 pulley, multi port WMI, Severn Tuning(pokeybritches), Tial, magnaflow,SS race muffler, 42 design,3.91LSD, H&R, Hotchkis,ST coils,Konis, Megan camber arms, AKG SS, Nylon mounts, Poly bushings, Carbon interior, CF Aero.APEX
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