chambered exhaust question
Thread Starter
Pro
Joined: May 2015
Posts: 571
Likes: 20
From: Milford, CT
I can't figure it out. the pics online of new cat back chambered exhaust systems clearly show 2 types. 1992-1995 and then 1996 is different but the pics look exactly the same. Aren't all the O2 sensor ports pre cat or actually on the cats? I know the 95 has 3 and the 96 has 4.
The reason I am asking is a complete 95 cat back chambered system is available locally and I have a 96.
The reason I am asking is a complete 95 cat back chambered system is available locally and I have a 96.
Burning Brakes
Joined: Aug 2008
Posts: 866
Likes: 220
From: Tampa, FL
I don't know for sure (I have an 84), but I'd have to say that the reason probably has to do with the number of O2 ports, based on the fact that the 1996 Corvette has OBD2, and is a different system. So, there might be a difference in size on the cats, etc.
Would you be replacing everything, or just cutting it and re-welding it in after the H-pipe anyway? If it's cheap, and you only need part of it... might be worthwhile.
Would you be replacing everything, or just cutting it and re-welding it in after the H-pipe anyway? If it's cheap, and you only need part of it... might be worthwhile.
Instructor
Joined: Apr 2017
Posts: 156
Likes: 36
From: Cleveland Ohio
You would need to add an O2 port on the driver's side exhaust pipe near the flange. When GM added a 4th O2 on the drivers side for '96-due to the way they drivers side cat assembly is made the port comes after the flange. It's easy to get an O2 bung and have a shop drill a hole and weld it in. I found in looking that many companies think the 4th port is only on LT4 engines so the catalogs get mixed up from time to time. If you buy that exhaust you would want to mock it up first so you know for sure A) the O2 port doesn't get welded in a spot where the harness is too short and B) if you have an auto trans it doesn't interfere with the O2 going in.
Thread Starter
Pro
Joined: May 2015
Posts: 571
Likes: 20
From: Milford, CT
You would need to add an O2 port on the driver's side exhaust pipe near the flange. When GM added a 4th O2 on the drivers side for '96-due to the way they drivers side cat assembly is made the port comes after the flange. It's easy to get an O2 bung and have a shop drill a hole and weld it in. I found in looking that many companies think the 4th port is only on LT4 engines so the catalogs get mixed up from time to time. If you buy that exhaust you would want to mock it up first so you know for sure A) the O2 port doesn't get welded in a spot where the harness is too short and B) if you have an auto trans it doesn't interfere with the O2 going in.
Pro
Joined: Mar 2007
Posts: 595
Likes: 355
From: Mt Prospect IL
2025 C4 of the Year Finalist - Unmodified
As already stated, the difference is the ‘96 has an O2 sensor on the drivers side just behind the flange. You can have a port welded on but use caution. If the angle is wrong it won’t clear the clutch slave cylinder (ask me how I know 😉
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Thread Starter
Pro
Joined: May 2015
Posts: 571
Likes: 20
From: Milford, CT
I have an automatic so that’s isn’t a concern.
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Thread Starter
Pro
Joined: May 2015
Posts: 571
Likes: 20
From: Milford, CT
Well… I think I got ripped off. I have been busy preparing this exhaust system to weld in the 4th O2 sensor bung and I decided to get out the leave blower and blow out the inside of both sides because I heard a rattle when I was moving it around. Well,,, about a pound of powdered rust and rust chips poured out of both sides. I am assuming it’s rusted baffles. Outside of the exhaust is pretty clean with only one small rust hole. Not sure what I should do at this point.
