Exhaust change over
Thread Starter
Intermediate
Joined: Jan 2011
Posts: 25
Likes: 1
Exhaust change over
Hi Everyone,
I recently went to a full dual exhaust system. I eliminated the air pump but have not removed the rest of the emissions parts on my 86. I have been driving the car for a few months and noticed that the exhaust gases smell like the engine is running rich stronger than normal gas order. Is there something else that I need to address or is this what I should expect after eliminating the cat and air pump? Any ideas?
Thanks.
I recently went to a full dual exhaust system. I eliminated the air pump but have not removed the rest of the emissions parts on my 86. I have been driving the car for a few months and noticed that the exhaust gases smell like the engine is running rich stronger than normal gas order. Is there something else that I need to address or is this what I should expect after eliminating the cat and air pump? Any ideas?
Thanks.
Le Mans Master
Joined: Dec 2005
Posts: 8,594
Likes: 981
From: Communist Colorado
You removed the converter and the smell is from that. I had done that before on a couple of Vettes.... couldn't deal with it and replaced the cats with hi-flow units from Magna Flow... You may be loose 3-4 HP, but its worth it in my opinion.
IIRC, the air injection pump only injects fresh air into the exhaust stream while the car is in open loop (warming up) to clean it up.
IIRC, the air injection pump only injects fresh air into the exhaust stream while the car is in open loop (warming up) to clean it up.
Last edited by 81c3; Jun 18, 2026 at 03:42 PM.
Burning Brakes
Joined: May 2005
Posts: 1,100
Likes: 38
From: Coldville
Yup, sounds like the Cat being gone is the smell.
I Run a High flow Cat, like the other guy said.
My other car is a 1980 Gp with a 71 Pontiac 400 that didn't come with a Cat and I smell that same thing.
Only smell it at start up in a garage though.
Driving around I don't smell it because the car is warmed up and Pontiacs run hot, so it Burns off that's smell and not a hint of smoke out the tailpipe.
I Run a High flow Cat, like the other guy said.
My other car is a 1980 Gp with a 71 Pontiac 400 that didn't come with a Cat and I smell that same thing.
Only smell it at start up in a garage though.
Driving around I don't smell it because the car is warmed up and Pontiacs run hot, so it Burns off that's smell and not a hint of smoke out the tailpipe.
Melting Slicks
Joined: May 2019
Posts: 3,290
Likes: 1,431
From: Mid-Atlantic
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Man. I envy you guys who don't live in states that dictate all of the emissions crap. If that were the case here I'd have had all of that stuff gone from month one of ownership.
****. They're dropping bombs all over the world, setting the planet on fire and yet they wanna give me some **** about my exhaust. Pft...
****. They're dropping bombs all over the world, setting the planet on fire and yet they wanna give me some **** about my exhaust. Pft...
Last edited by Natty C; Jun 19, 2026 at 11:46 AM.
