ok. i see what everyone is saying about free flowing exhaust creating more power and better efficiency, but i think we might be overlooking the 02 sensors. no cat means the rear o2 sensor is always gonna read rich. that causes the check engine light but it will also cause the computer some trouble because its gonna try to lean it out which will cause a discrepncy between the pre cat and post cat o2 sensors. its just my theory though. i had the same question. can anyone with the gutted cat post any mpg loss or power loss? any gained? besides sound

 

gutted mine a year ago, and no code or CEL or anything. just got a drone and slight loss of low end power. i hear going with a high flow cat you get the same sound, and no loss of power.

if you do it and get a CEL light you can order an 02 sim that wont throw any codes.

 

lose mpg's?

 

Gutted mine about 3 months ago. Took a month for the check engine light to come on. Haven't installed a sim yet or tried the non fouler trick. But I have noticed no difference in mpg's. I even ran a steady 15 mpg on the highway during my trip out west last month.

 

Ok so im gunna cut it off and just put a stait pipe there that should be ok?

 

I get a P0420 Low Catalyst Efficiency every so often with my gutted cat and glasspack, it'll stay on for a couple weeks then go out if I don't clear it first.

with that setup it drones along at ~2 grand but it's a nice, deep LOUD tone that sounds really good. People definitely know when I'm coming, and I'm sure I've scared the **** out of numerous people I've passed right on the hammer haha.

 

Has anyone noticed a loss in power after gutting it?

 

Gotta Gut mine sometime soon, No work right now so no need to get in a hurry. I do not like the way the cat has two inlets and one outlet. Makes it kinda difficult to just remove it and replace with a straight pipe. Figure I'll just chop the pipe after the cat get the 3ft pry bar and driver home! rev it all out. Anybody done this before? I heard it works but makes quite the mess.

 

Cutt off at the Y, unless you have inspections it's easier to just cut the cat off and weld in a soild piece of pipe

 

My cat is actually the "Y" 2 pipes going into the front of it and one coming out the back. Single exhaust.