Pre-cats
Team Owner
Joined: Sep 2001
Posts: 62,153
Likes: 1,731
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
All from 86-91 have them stock.
If you dont then someone replaced it, but the precats dont affect emissions that much (once the engine is hot) if the main cat is good. Once the engine is hot then you'll pass a sniffer.
If you dont then someone replaced it, but the precats dont affect emissions that much (once the engine is hot) if the main cat is good. Once the engine is hot then you'll pass a sniffer.
Instructor
Joined: Jul 2005
Posts: 140
Likes: 2
From: RI
I have a 1988 convertible with 4+3, and it came factory with precats. The original front y looked to be 2.25 inches in diameter, and I just upgraded to a new 2.5 inch y with precats and magnaflow converter. It definately feels more powerful.
