I have searched but can’t find an answer to this specific question: what ID size is the down pipe from the manifold to the cat? If there’s a thread, please point me to it, as there will be more to read and possibly learn from. Thank you!
2000 SSEi
-Ryan
Exhaust question
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AnthonyK
- SE Member

- Posts: 12
- Joined: Fri Feb 07, 2020 5:48 pm
- Year and Trim: 2005 Pontiac Bonneville SLE
Re: Exhaust question
I looked on the ZZP site and they claim the inside diameter of the factory downpipe from the manifold to the cat is just a little over 2". Hope that helps
Re: Exhaust question
It does, thank you. I hadn’t thought to look on their site.

