removing the cat - BMW Forum

MiguelACA · 08-08-2006, 11:08 PM

would removing the cat from my 325i make my exhaust too loud? like ricer loud?

Ivan · 08-09-2006, 12:02 AM

it would probably sound pretty mean actually. but it would be uber loud and pretty unbearable, it would drive you nuts.

Quinn328is · 08-09-2006, 12:05 AM

ivan's right, might make the neighbors a little mad

preyash · 08-09-2006, 12:28 AM

Quote:

Originally Posted by MiguelACA

would removing the cat from my 325i make my exhaust too loud? like ricer loud?

Yea actaully my friend has a turboback exhaust in his eclipse with no catalytic converter, his car sounds like a car that has gone retarded, but it sure does increase a little hp after the cat is removed. u can also see sparks comin out if u rev it really hard.

MiguelACA · 08-09-2006, 01:12 AM

hmmm...the muffler shop guy said it wouldnt be too loud since i still have the stock muffler and silencer, my mechanic said the same thing, any other opinions, if its going to be super loud, like ricer loud, then i wont do it, but if it will amp it up just a bit to get a nice sound, wut do you guys think?

WarNox · 08-09-2006, 02:29 AM

wouldnt it be illegal and fail some emmisions test you guys have to pass anyway? i'd rather get a proper exaust system.

ps. nice avatar preyash

Ivan · 08-09-2006, 02:38 AM

oh, i thought you meant you were going to remove the exhaust completely from the cat back, like open headers. if you have the muffler still on and such it shouldnt be too bad.

MiguelACA · 08-09-2006, 01:27 PM

we dont have emissions tests down here, and i just wanted to take off the cat and put pipes in its place, keeping the original muffler

MiguelACA · 08-10-2006, 03:31 PM

anyone?

e36surge · 08-11-2006, 10:07 AM

Okay Miguel here's my take on this.

We don't have emissions test 'yet' in Montreal. When my exhaust started going this spring I took it to my mechanic who's a good friend of mine.

We removed the CATS and the resonators. I also ran a 3" pipe from after my O2 sensor all the way to an aftermarket RAVIN' exhaust.

RESULT: When we started the car the entire garage (5 bays) started vibrating and it was way too f##king loud.

We then went on to adding a single cat. Result, so loud I set off alarms as I drove by. So loud my teeth started to hurt. So loud it was loder in the car than outside.

So we added another CAT in line with the other cat. remember all along keeping the 3" pipe we added from after the O2 sensor. We also removed the RAVIN muffler.. too loud at idle but it sounded real sweet on the highway but added a regular aftermarket exhaust.

In the end I now run a 3" exhaust into two high flow CATS and one resonator and a regular exhaust with a dual tip.

No engine light or check engine or any other error codes appeared since the install and my mileage has remained the same. She just sounds a little 'throatier' and just a little louder than factory.

this was done on a 1995 325is.

Tochenzo · 08-11-2006, 12:09 PM

3" exhaust = competely unnecessary on a n/a car, you will actually only lose torque and won't have very much hp gains either

if you replace the cats with straight pipes, i'd suggest getting a high flow muffler along so it isn't too restricted once it hits your stock cat-back

look into the trackpipe through aa and turner, expensive but well crafted and they aren't incredibly loud as long as you have a nice cat-back, but it sounds mean as hell at WOT

MiguelACA · 08-12-2006, 03:07 AM

im just looking to take of the cats for now, i was told u get a slight hp boost, im just not sure if taking the cats off and replacing them with straight pipes, normal size as the rest of the exhaust, if it would be too loud afterwards

e36surge · 08-12-2006, 08:30 AM

I was merely stating what I did and what happened. I have not lost HP or torque. I did not do this for performance or even the sound. I did it because I didn't see the need to spend so much money on an OEM replacement on an 11 year old car. My mechanic told me it would just be louder

I have a wife, a dog and car, and they're getting more and more expensive to maintain.. in that order.

325IConvertible · 08-12-2006, 01:30 PM

hahahah " we don't have emissions test down here " Man where in Texas do you live ? I need to move to that part. I would stick to using a full exhaust myself. Certain car's you can lose the Cat or some even the muffler and get a decent sound and better performance but when it comes to just a little bit of increase then it isnt worth it ........... Plus think of law enforcement around you ??????? come on man this is TEXAS lol the law loves messing with car guys. Go to a new full exhaust .... from what I see BMW has a lot to offer.

MiguelACA · 08-13-2006, 03:22 AM

Quote:

Originally Posted by e36surge

I was merely stating what I did and what happened. I have not lost HP or torque. I did not do this for performance or even the sound. I did it because I didn't see the need to spend so much money on an OEM replacement on an 11 year old car. My mechanic told me it would just be louder

I have a wife, a dog and car, and they're getting more and more expensive to maintain.. in that order.

i understand what youre telling me, i agree, im not looking to spend to much on my car at this moment since im going back to school, just looking for a bit more sound and from what ive heard, hp gain

and 325icon. i live in mcallen, tx, way the hell down south, we have to get yearly inspections, but no emissions, just the normal turn signals, brake lights, stuff like that