Catback exhaust 2.25" w/ 2.5" DP and cat - Cobalt SS Network

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Catback exhaust 2.25" w/ 2.5" DP and cat

2.2L L61 Performance Tech 16 valve 145 hp EcoTec with 155 lb-ft of torque

Catback exhaust 2.25" w/ 2.5" DP and cat

Old 09-20-2018, 07:48 PM
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Catback exhaust 2.25" w/ 2.5" DP and cat

I really want to get a header for my Cobalt. The problem is, long ago in 2013 I decided to go with a 2.25" catback.

ZZP Performance has a midlength header that looks perfect for what I want... but...
The DP included is 2.5", with no option to go 2.25".

I chose 2.25" because it is a 2.2 liter 4 cylinder engine.
The hp doesn't warrant a 2.5" exhaust, and I worried about not enough back pressure damaging the engine.

If I get this 2.5" DP and cat, is this going to make the car drive bad?

Going from a larger pipe to smaller is the opposite of optimal.
Plus, the question of back pressure and the obvious problem of mismatching.

Opinions please?

Thank you!
Mike85220 is offline  
Old 09-21-2018, 08:09 PM
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No it will be fine. I had the same setup
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Old 09-26-2018, 09:00 AM
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On a non-boosted 2.2 you most likely won't see a performance gain with an aftermarket header anyway so keep in mind this mod will be mostly for looks/sound. You may even lose some low end torque. That said, the reduction from your header downpipe to the back side of your exhaust is probably insignificant and I wouldn't be concerned about it.

Also, engines benefiting from back pressure is a myth. Engines do not need back pressure and back pressure is not good for engines. This myth is a misconception of power losses associated with larger pipes because of the reduction in exhaust gas velocity, compared to smaller pipes, which can reduce the effects of scavenging. Short summery here
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