modified stock downpipe

NotAcamaro · Jul 14, 2018

I've been debating modifying my stock down pipe to remove the 2 1/4 bottle neck.
I have a 2.5in cat back and im considering removing the 2 1/4in section of the stock down pipe and replacing it with some 2.5in pipe.
has anyone done anything like this?

Chef jpd · Jul 14, 2018

If the only purpose of this is so the DP will mate with your exhaust, go for it. It will eliminate the choke.
The other option is a 3" catted downpipe, in which case the exhaust will be the choke. but that is another can of worms .

Another option is to take the downpipe to an exhaust shop and have them stretch the 2.25 section to 2.5.

NotAcamaro · Jul 15, 2018

Chef jpd said:
If the only purpose of this is so the DP will mate with your exhaust, go for it. It will eliminate the choke.
The other option is a 3" catted downpipe, in which case the exhaust will be the choke. but that is another can of worms .

Another option is to take the downpipe to an exhaust shop and have them stretch the 2.25 section to 2.5.

The exhaust has a 2.25 reduction so it can mate up to the downpipe.

My main goal is to remove some of the restriction in the exhaust without ditching the stock cat.

I had not thought about having it stretched, I'm not sure how that would work with the flex pipe

Marvinmadman · Jul 15, 2018

The flex section is pancaked also

Elgyn · Jul 16, 2018

i did that, changed the flex pipe to a larger one and removed the resonator. It's worth it if you have a tune and want to keep the stock cat to avoid a check engine light

modified stock downpipe

NotAcamaro

New Member

Chef jpd

Well-Known Member

NotAcamaro

New Member

Marvinmadman

Well-Known Member

Elgyn

Well-Known Member