Removing Stock Cat
Le Mans Master
Joined: Jul 2000
Posts: 6,559
Likes: 4,501
From: North Dallas 40 TX
No tune necessary. The C8 has wide band O2 sensors and functions in closed loop all the time, except start up and limp home. As for cost? how are your welding skills? If none, there are bypass pipes with new gaskets for $420 if you can install them yourself.
Thread Starter
Navigator
Joined: Aug 2022
Posts: 9
Likes: 0
so I won’t get a check engine light if I do this? And I plan on just taking it somewhere after I get the part and having them install it
Safety Car
Joined: Jul 2019
Posts: 4,079
Likes: 2,411
From: Florida
Last edited by bhvrdr; Oct 31, 2022 at 09:42 PM.
Thread Starter
Navigator
Joined: Aug 2022
Posts: 9
Likes: 0
How do I combat or fix these issues? and how much performance can I expect to receive from it?
Safety Car
Joined: Jul 2019
Posts: 4,079
Likes: 2,411
From: Florida
Speedy
Joined: Mar 2007
Posts: 6,073
Likes: 903
From: Tn
2024 C8 of the Year Finalist - Modified
I used defoulers when I decatted my bmw and would go 5 to 600 miles between lights. I tried a O2 spacer on the c8 and get the light every 50 miles.
I never used a mini cat but don't recommend it because there's no guarantee.
Below is a obd2 blutooth adapter
https://www.ebay.com/itm/25519817761...hoC4L0QAvD_BwE
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Thread Starter
Navigator
Joined: Aug 2022
Posts: 9
Likes: 0
I use a Bluetooth obd2 adapter to run torque and auto clear the CEL. The light doesn't bother but you can't remote start if it's illuminated at shutdown
I used defoulers when I decatted my bmw and would go 5 to 600 miles between lights. I tried a O2 spacer on the c8 and get the light every 50 miles.
I never used a mini cat but don't recommend it because there's no guarantee.
Below is a obd2 blutooth adapter
https://www.ebay.com/itm/25519817761...hoC4L0QAvD_BwE
I used defoulers when I decatted my bmw and would go 5 to 600 miles between lights. I tried a O2 spacer on the c8 and get the light every 50 miles.
I never used a mini cat but don't recommend it because there's no guarantee.
Below is a obd2 blutooth adapter
https://www.ebay.com/itm/25519817761...hoC4L0QAvD_BwE
Speedy
Joined: Mar 2007
Posts: 6,073
Likes: 903
From: Tn
2024 C8 of the Year Finalist - Modified
People insisted I use a O2 sensor spacer on the corvette to prevent a check engine light but they did not work. When I was purchasing from Fabspeed they could not guarantee their mini cats so i couldn't justify the added cost of that solution either. I had better luck on my 2020 M2 using spark plug defoulers drilled out to fit the O2 sensor and would keep the CEL off for about 500 miles.
Removing the cats adds a smell that some may not like. It makes the exhaust pop more on decel. Adds about 20-30% volume
My camera should be arriving today and if it does ill get you videos.
Le Mans Master
Joined: Jul 2000
Posts: 6,559
Likes: 4,501
From: North Dallas 40 TX
The power gains are not that great from the reports I have read. Mostly sound. You would have to have other mods to need the extra flow. The stock cats have huge openings. Bigger than most standard aftermarket cats.
Racer
Joined: Oct 2017
Posts: 342
Likes: 87
From: Dallas, Texas
I had Soul Performance sports cat with stock exhaust, it sounds great especially if you want to retain the AFM valves, most importantly no CEL.
I now upgraded the paragon exhaust so no need for the sports cat, hit me up if you interest in them.
I now upgraded the paragon exhaust so no need for the sports cat, hit me up if you interest in them.
Melting Slicks
Joined: Aug 2000
Posts: 2,317
Likes: 1,115
From: Early 2020 Z51 Coupe, Original Owner, Ahwatukee Foothills, AZ
Have the HJS 200 Cell Cats as well with the NPP stock exhaust and the sound is just right.
Thread Starter
Navigator
Joined: Aug 2022
Posts: 9
Likes: 0
you think I’d he beret off with a muffler delete? Or would suggest different cats? I don’t plan on adjusting my exhaust at all.
Speedy
Joined: Mar 2007
Posts: 6,073
Likes: 903
From: Tn
2024 C8 of the Year Finalist - Modified
Racer
Joined: Oct 2017
Posts: 342
Likes: 87
From: Dallas, Texas
Very simple if you track your car and don’t mine the obnoxious noise then go with test pipe, you might gain a few more hp. Otherwise stick with sports cat to eliminate CEL.
Pro
Joined: Apr 2019
Posts: 688
Likes: 415
From: Armonk, NY
In what way do the defoulers impact "metering"?
Melting Slicks
Joined: Jan 2006
Posts: 2,220
Likes: 1,783
From: Oregon
Performance gain; next to nothing, maybe a few HP. Bad smell, if you back up into a parking place, you will smell strong exhaust smell. Why bother? It will never pass DMV or DEQ.
It may sound different, but overall not worth the trouble. I had a no cat racecar that I drove on the street, every time I came to a stop sign I could smell that nasty exhaust. I put high flow cats on it.
It may sound different, but overall not worth the trouble. I had a no cat racecar that I drove on the street, every time I came to a stop sign I could smell that nasty exhaust. I put high flow cats on it.
Burning Brakes
Joined: Oct 2019
Posts: 801
Likes: 513
From: Colorado Springs
Fun starts about 25 minute mark. 20HP gains. https://www.youtube.com/watch?v=E23z3UtwMOQ