I pulled the cats off my mustang, no problem at all, they were downwind from the O2 sensors so no codes were generated. The exhaust gets louder and what comes out the pipes is more noxious.

 

And in most states you will fail your state inspection (if you have one).

On my old Camaro I had an exhaust shop make me up some "test" pipes that went in place of the cats. They could be swapped out in less than an hour so I would put the cats back on when getting it inspected. One problem you will have is the air pump which expects there to be a cat. Since on the camaro it was a seperate belt, I just removed the belt so the pump was disabled too.

 

Back when cats were first mandated, they were atrocious, and removing them was possibly the best thing you could do for performance. Things have changed a lot since the 70s.

In many instances, removing the cats in a modern car can actually cause worse performance than leaving them on. For high-revving, especially turbo engines, you want as little exhaust back pressure as possible. For high-torque engines, some backpressure actually makes for better performance.

Note the relative torque and horsepower numbers for your model year.

The engine was designed, built, and programmed for the cats. Removing them will require a pretty comprehensive approach to achieve efficiency.

And may result in a $500 per missing cat fine.

Can you tell that I'm generally against it? Not for any treehugger reasons, but for performance ones.

Woody

 

Back when cats were first mandated, they were atrocious, and removing them was possibly the best thing you could do for performance. Things have changed a lot since the 70s.

In many instances, removing the cats in a modern car can actually cause worse performance than leaving them on. For high-revving, especially turbo engines, you want as little exhaust back pressure as possible. For high-torque engines, some backpressure actually makes for better performance.

Note the relative torque and horsepower numbers for your model year.

The engine was designed, built, and programmed for the cats. Removing them will require a pretty comprehensive approach to achieve efficiency.

And may result in a $500 per missing cat fine.

Can you tell that I'm generally against it? Not for any treehugger reasons, but for performance ones.

Woody

Hello, Thank-you for your reply. After talking to a few others, most agree today's cars, removing the cats make cause many other things to go out of adjustments.

Therefore I will leave them on and NOT change to higer flow ones too...Aloha