Mike85220

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!

chevygirl2006

jdbaugh1

iTrader: (1)

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