86 catalytic converter removal issues
Instructor
Joined: Apr 2013
Posts: 104
Likes: 2
From: Greenville SC
If your 86 is anything like the 88 Vert that I have as a project car, I'm pretty sure the o2 sensor is in front of the CAT, so the car shouldn't know the difference, but the last I understood, there comes a hefty fine for getting caught removing CATS.
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Yes you can remove them without any codes. The O2 is upstream of all the cats on the driver's side, it'll still reach the requisite temperature.
Thread Starter
3rd Gear
Joined: Apr 2014
Posts: 3
Likes: 0
Searching for power and a better sound
luckily I live in a state where they don't check emissions or regulate cat removal much unless you are doing it for the public. Don't ask. Don't tell. Seems like the cat being after the sensor still can be affected because the cat builds up a lot of heat before it by stopping the flow dramatically.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
The O2 sensor sits just below the driver's side exhaust manifold/pipe flange. The left side pre-cat is about 8-10" past that.
I have run my '87 with true duals and kept the O2 sensor in the stock location. I now have Hedman headers and I moved the O2 sensor to the reducer where it bolts to the collector. No codes.
As mentioned, there is a huge fine (5 figures
) if a shop gets caught removing working converters and not replacing them. In California, most aftermarket converters can't even be used as direct replacements. Gotta have that CARB sticker 
I have run my '87 with true duals and kept the O2 sensor in the stock location. I now have Hedman headers and I moved the O2 sensor to the reducer where it bolts to the collector. No codes.
As mentioned, there is a huge fine (5 figures
) if a shop gets caught removing working converters and not replacing them. In California, most aftermarket converters can't even be used as direct replacements. Gotta have that CARB sticker
