Exhaust Width Question

[JustinSane8000]

Hey everyone, i have a 2g eclipse, with a 1g 6bolt swap with the 14b turbo running at 15psi. im kinda in an awkward situation.

a while ago i decided to build my exhaust (which as of now, is stock) so without doing much research, , i went and bought a 2.5 high flow cat a couple weeks back, and i just bought a 3'' catback system. so my question is,

how will this effect my system. I'll be using the stock downpipe, with the 2.5'' high flow cat, and a 3'' catback system.

im assuming i wont get the full exhaust power gains. but in a few weeks, im going to buy a 3'' downpipe. so will i be able to keep the 2.5'' cat with the 3'' downpipe & 3'' catback system? or do i need to buy a 3'' cat?

thanks alot

 

[S_Ranger]

If it was a smaller diamater I'd be more concerned. But really it's the manifold port, o2 porting, that makes the real difference. You'l notice a different sound and some increase in hp but you have nothing to worry about.

 

[UMR98GSX]

Anything worth doing is worth doing right. Ditch the 2.5" cat in favor of a 3" model. Your exhasut is only going to flow as well as it's weakest point. Although 2.5" is plenty for your current setup, if you should ever choose to upgrade you will see better gains with a full 3" exhaust.

 

[donmagicjuan]

My question is how do you plan to fit the 3" downpipe to the 2.5" cat? Catalytic converters are already the most restrictive components in an exhaust. My advice would be if you want to run a 3" downpipe, get a 3" high-flow cat to go with it. If you want to keep the 2.5" cat, then just get a 2.5" downpipe. The latter should still be sufficient for over 300 whp.

EDIT: Too quick for me, Anson.

 

[S_Ranger]

I'm sure you can sell teh 2.5" hi flow cat and flip it to buy a 3". This is probably done on a budget so I know how that is. Good luck with your project.

 

[UMR98GSX]

Andy has been teaching me! Quick reply is AWESOME

 

[donmagicjuan]

Yeah, he schools me with his fast typing all the time!

 

[JustinSane8000]

i used ebay to get the 2.5 for like 25$, the only 3'' cats i see on ebay are around 50-60... any sites that sell for cheaper?

im saving as much money as possible for the 16g, with a goal to have here in 1 month

 

[brute]

I've been struck by Andy on many occasions as well.

 

[UMR98GSX]

I picked up my 3" HF cat from a place on ebay with a "best offer" deal. I think I payed $52 for it so you are not really out of the ballpark on this one. Mine is a magnaflow and works great considering that a Random Tech or other application specific cat will run you well over $100.