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Discussion Starter · #1 ·
Just curious here, but noticed something this past summer while trying different catback systems. I’m running a 3” dp and many catback systems are 3”. However I’ve noticed that most all aftermarket catback systems have 2.5” flange on them. Obviously they’re designed to be used with the stock dp. But I’m curious to find out from those more knowledgeable. Does that small section create any kind of bottleneck resulting in possible power loss? Would there be any benefit if the 2.5” flange were cut off and replaced with a 3”? Or would it not be a worthwhile endeavor. Feel free to flame away at me for asking. :banana:
 

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While I do not like the idea of there being a neck-down in the system, it will not rob you of any HP when looking at a 2.5" flange on a 3" system.

A 2.5" exhaust will support plenty of power on these cars and you wouldn't notice any type of hinderance until you start marking serious power. Even then it's going to be negligible.
 

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Discussion Starter · #3 ·
While I do not like the idea of there being a neck-down in the system, it will not rob you of any HP when looking at a 2.5" flange on a 3" system.

A 2.5" exhaust will support plenty of power on these cars and you wouldn't notice any type of hinderance until you start marking serious power. Even then it's going to be negligible.
Yeah, was just a thought. If there were any appreciable gains I'd consider it.
 
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