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RarlyL8 RarlyL8 is offline
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Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,525
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USA pre-'86 heat exchangers are restrictive to the point that they will not allow bolt-on upgrades to work optimally. You cannot get an accurate dyno comparison on a modded engine because of that. If you were to swap the US exchangers for headers on a stock US engine with a stock muffler you would probably see 20HP. I have never done that test.

Euro heat exchangers will support 400HP and when swapped out with headers will add maybe 20HP or so. More importantly though a proper header design will reduce lag, increase torque, and allow bolt-ons and internal mods to function optimally. You cannot say headers are worth 100HP if X turbo is used. X turbo is giving the 100HP, the headers are facilitating that action.

The more mods you have the more important header design is to function.

Free flowing mufflers make a similar difference in power and engine characteristics.
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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 02-21-2008, 05:52 PM
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