c didy

Anybody with experience with standard primary "Cup" bypass, cat bypass, Wong chip combination:

I put a primary bypass on a couple months ago and it's great. Just got the cat bypass on last week, sounds fine. A bit louder but not bad. It really is light and looks great but now the car stinks even more than my '72 w Webers. Sure smells rich. Did it do that for your car, or will the map in my Wong chip help, (not in yet), or is it a sign that there is something else wrong? O2 sensor maybe?

I know the exhaust is probably not going to be the same as with the cat and maybe part of the problem is that I didn't get the clamps tight for good enough seals so I am getting exhaust in the cabin but they sure seemed pretty well seated. I don't want to be stinking up the place and I've heard that these cars burn clean enough to pass emissions without the cats so I think I'm missing something.

crg53

I have the exact same set up on mine and have never noticed any smell. I would install the SW chip and see what happens, you will definitely notice a difference in response and power.

P.S. If that is your car in the avatar, please show us some more pictures.

FeralComprehension

Remove the cat and of course you're going to smell it; the job of the cat (in part) is to burn any unburned hydrocarbons (=gas...) that escape the combustion chamber.

These cars run rich; part of the reason the mileage is so dreadful. Race cat is probably a better choice.

Jacke2c

I would bet it is weak or going... or is bad. I have the primary muffler bypass, and cup pipe and I get little or no smell, but I changed the O2 sensor when I installed the bypass.

PNine64

I have a cat bypass, primary bypass and SW chip. I smell fuel on occasion but figure that's what living a little less civilized feels like.

c didy

The O2 sensor seemed to be fine with the stock exhaust and the Cup Pipe. No problem at all since I purchased the car until I switched to the cat bypass last week. I disconnected it in the engine bay before removing from the cat. If it wasn't reconnected right would it show as a CEL?

c didy

'72, 2.7, glasurit Gold Metallic (original color)

Cosmos99

I have a cat bypass and primary bypass with the SW chip. When I did the swap I changed the O2 sensor because I assumed that it was 19 years old. The car runs rich ( a little soot here and there on the bumper ) and I smell some, but very little exhaust gas smell while sitting still. I assumed thats what would happen when removing the cat. Not bad at all and way less than some of the 70's muscle cars in my neighborhood.

c didy

Did this and found some leaking at the Cat-bypass/Cup Pipe joint.

"Start your car and then put something thick and non-flammable (it will get really hot within about 3 seconds so be careful)against the tail pipe, completely blocking it. If there is a leak you'll hear it right away. "

https://rennlist.com/forums/964-foru...eak-sound.html

I ended up seeing it more than hearing it. Water vapor was easy to see in my cold car. Gotta get it sealed.