If i have a 2.5" catback would it make sense to get a 2.5" downpipe with high flow cat, or is there a benefit to getting a larger downpipe? (Will it bottleneck at the 2.5" exhuast anyways? etc...)

And I already searched, nothing specific came up. Thanks in advance

 

I would get a 3" downpipe and have it bottleneck down to a 2.5 so it will fit the cat-back.

 

^^What I did.

 

your exhaust is only as big as the smallest point in the exhaust system. i do not see a 3'' dp going to a 2.5'' cat back being helpful. I could see it creating flow problems. talk about air turbulence. you best bet would be to get a 2.5'' dp with a high flow cat, or catles

 

yah thats what my common sense was telling me, keep the same size for both or it will have a bottleneck, i just wanted to here it from someone who knows more about exhausts than i do, thanks.

 

Yeah i never thought about the airflow being weird with the neck down on my ZZP. maybe that's why it makes so much noise.

 

its all about cfm's lol