deleting cats?

E36cruiser · #1 (**permalink**) 12-31-2007, 10:43 AM

I was looking at my exhaust while doing my engine and tranny mounts the other day and it looks like it would be simple just to cut off the cats and put strait pipes in place of them. Has anyone done this or atleast done the equivalent by putting a catless mid pipe on? I want to hear what it sounds like with the stock muffler.

villlein · #2 (**permalink**) 01-01-2008, 09:51 PM

it's been done. very loud. very illegal, and easy for cops to pick up on. im sure you can find youtube videos of it.

BadGTho · #3 (**permalink**) 01-03-2008, 06:47 AM

many people have done this.. the car will sound pretty sweet... but as mentioned above, it's against the law.

in an OBDII car, you will get a CEL unless you take appropriate measures to prevent against this.

E36cruiser · #4 (**permalink**) 01-03-2008, 03:09 PM

Well I have a local exhaust guy that will actually cut my cats in half and then wrap them around the strait pipe to make it look like it has cats. I'm just curious how it sounds and if it benifits the car.

petar7408 · #5 (**permalink**) 01-03-2008, 07:10 PM

on a turbo car YES, not on your car though

vfr-rich · #6 (**permalink**) 01-04-2008, 07:13 AM

No benefit at all, felony. $25,000 fine and prison for shop owners. I'm never surprised by the stupidity of others. Makes your car stink, screws up my air. Don't do it.

There are some performance benefits for using aftermarket high flow cats, but there are cats, and they do work.

itsabimmerthing · #7 (**permalink**) 01-08-2008, 03:09 PM

Yes, it does add performance. As for the cop thing, no, most cops will not pick up on it unless echecks are done in your area. Most cops have no idea what the hell their looking at. I had a cop get under my car and look for a cat, which it didnt have, and claimed he seen one and let me go. As for performance gain, it is pretty good. I would go for it personally. OR, if you want to do it, and look legal..... You can gut the cat, and get just about the same results. Who cares about the air anyway. We are all going to die some day anyway. When its our day, their is nothing we can do.... Might as well enjoy life while we can.

E36cruiser · #8 (**permalink**) 01-08-2008, 03:49 PM

Quote:

Originally Posted by itsabimmerthing

Yes, it does add performance. As for the cop thing, no, most cops will not pick up on it unless echecks are done in your area. Most cops have no idea what the hell their looking at. I had a cop get under my car and look for a cat, which it didnt have, and claimed he seen one and let me go. As for performance gain, it is pretty good. I would go for it personally. OR, if you want to do it, and look legal..... You can gut the cat, and get just about the same results. Who cares about the air anyway. We are all going to die some day anyway. When its our day, their is nothing we can do.... Might as well enjoy life while we can.

I like how you think... hah, werd. prob. just gutt the cats out tomorrow, thanks for the advice.

Motorsport3 · #9 (**permalink**) 01-08-2008, 03:53 PM

Why don't you just buy a AA track pipe?

E36cruiser · #10 (**permalink**) 01-08-2008, 04:02 PM

Quote:

Originally Posted by Motorsport3

Why don't you just buy a AA track pipe?

Because I saves money and "if" i get pulled over it still looks like I have cats... once I do headers then maybe i'll get a trackpipe at the same time.

itsabimmerthing · #11 (**permalink**) 01-08-2008, 04:16 PM

There you go. No point and buying an expensive ass track pipe. To be honest if I want a full strait pipe, I do the following:
I fab myself the strait pipe using the existing flange.
I then procede to weld a heat sheild around the test pipe (strait pipe) and cops cant tell the difference. Why buy one, when you can make one is my philospihpy.

E36cruiser · #12 (**permalink**) 01-08-2008, 04:47 PM

yea, same idea as i said w/ cutting the cats in half and welding them around... question, witht he pack of four there, are 2 cats and the other 2 resonators?

92318is · #13 (**permalink**) 01-27-2008, 03:40 PM

No benefit at all? Do you know what you're talking about??

And its not just a benefit to turbo'd cars, although I do have just a straight pipe running from my turbo back, and when I have to pass emissions, I just put the stock cat back on. I can tell a huge difference, but even on a non-turbo car it will add more power. And I don't notice any "stink" from not having the cat. The cat adds restrictions to the exhaust...we all know a less restrictive exhaust = more power.

itsabimmerthing · #14 (**permalink**) 01-27-2008, 04:54 PM

Quote:

Originally Posted by 92318is

No benefit at all? Do you know what you're talking about??

And its not just a benefit to turbo'd cars, although I do have just a straight pipe running from my turbo back, and when I have to pass emissions, I just put the stock cat back on. I can tell a huge difference, but even on a non-turbo car it will add more power. And I don't notice any "stink" from not having the cat. The cat adds restrictions to the exhaust...we all know a less restrictive exhaust = more power.

Wow, another DSMr, same here man. Us DSMrs know about taking cats off lol. Hell yea it adds power and spoolup. Plus the 4g63 sounds awesome without it lol.

andresvillanu20 · #15 (**permalink**) 02-13-2008, 02:34 PM

what about the O2 sensors, arent they going to read any diff. and mess up your performance?