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RarlyL8 RarlyL8 is offline
Crotchety Old Bastard
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Join Date: Jan 2000
Location: Huntsville, AL
Posts: 14,083
The cat bypass is 2.75" pipe and the muffler is chambered with many restrictions. Picture is below. My system is straight through 3". The difference is not tremendous in terms of HP; the greatest benefit is the combination of boost lag reduction, sound, and throttle response.
K27-7200, IC, and 1bar on a stock late USA engine will get you about 280WHP. I prefer to gain power in other ways than increasing boost. More boost = more engine stress. My engine puts out 350WHP with stock boost using large IC, my headers/muffler and SC cams.

RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 07-08-2011, 05:57 AM
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