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Old 08-02-2019, 07:50 AM
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HWYSTR455 HWYSTR455 is offline
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Join Date: Jan 2005
Location: Manassas, VA
Posts: 12,542

I have an issue with those 2 Hot Rod Mag tests. First test, it's with a 355ci, second test, no H or X pipe.

H and X pipes provide additional flow between exhaust cycles across the crossover pipe.

All know an X works better than an H, though sometimes it's not possible to 'fit' and X pipe due to clearance issues. Same with 3" tailpipes, sometimes you just can't fit them over the axle or past the tank.

Sometime when using OE looking tips, the larger 3" type repops just don't look right.

I bet if that second test had an X pipe, you would see less of a gain between a 2.5 and a 3" exhaust. But still agree there would be SOME difference. 10-15hp I think would be a max difference with a 600hp engine, and you do lose some TQ on the bottom end with larger pipes. So for roughly a 2% loss, I consider that nominal, and acceptable, in an event you don't want to run 3" tailpipes. When you have 600+, unless you are competing, 2.5 tailpipes are just fine.



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