Engine Drivetrain 2nd Gen S Most liked posts in thread: 2nd Cat Delete

It depends on what you consider an improvement in sound. Without a resonator higher frequency notes become apparent; they are the main cause of rpm specific resonance and impart a tinny quality to the exhaust note. Rather than a straight pipe, I would recommend the JCW section with the long resonator, RealOEM.com * BMW R56 Coop.S JCW CATALYTIC CONVERTER/FRONT SILENCER, slightly less back pressure and clips the high frequencies.

 

I have run my car with the second cat, without the second cat and also without any cats. I have to say that I didn't notice that the sound was annoying with the second cat removed. It does however get VERY loud without a downpipe cat. In all cases I have left the resonator on.

Keith, you seem to be talking about the resonator, I believe the OP is referring to just removing the cat.

I have seen that many people are happy with the JCW exhaust, I just don't have any personal experience with it.

I will also say that you will not notice any performance increase by removing the cat. You might think you do, because the car will be louder, but I doubt there is any actual increase.

 

Yes, I now see at as only the post-cat and not the entire section. I'm familiar with the JCW exhaust and like its sound more than any other, aftermarket or the stock exhaust. I know its lower tone is due to the longer resonator. There's a good chance I'll be installing the JCW in a customer's car soon, and reports from others who've made the switch sound like this MINI COOPER :: North American Motoring - Seeking suggestions regarding my R56 JCW stage 1 exhaust
.

 

Justa NOTE. It is a FEDERAL Law on the emissions!! IF you remove the cats , you ARE in violation of Federal Law.

But hey that must be cool... as the Feds dont know the meaning of the word "Illegal" either!! LOL

Just me........................................

Thumper

 

Thumper.........
You are correct for the street.
But, off the public streets (off road), such as race tracks etc., I believe there is an exemption. Correct???

 

Race tracks are not public roads, so none of the rules apply. On the track you play by big boy rules.

 

Yes.. there must be NO Tags and the Car has to be regerstered as an OFF ROAD Only!!

but as said... who cares, and no one checks anyways!! LOL

Thumper

 

It's a Texas Law too ...

http://www.tceq.state.tx.us/assets/public/legal/rules/rules/pdflib/114b.pdf

 

You only need one cat so it is ok to take one off.
This really applies to N/A cars more then boosted but thought I would put it here anyway.
http://www.importtuner.com/features/0610impp_catalytic_converter_removal/index.html

 

Be kind to our environment, leave the cat on.

 

LOL... it IS the LAW!! any where here in the US!!

Thumper

 

Before I got my custom 2.5" magnaflow exhaust I had my 2nd cat and resonator removed. If you just get the 2nd cat removed it probably won't be noticeably louder, but a little more free flowing. If you also get the resonator removed it will be a little louder/raspier past 2.8 rpm on up depending on how hard you accelerate. I liked it and pretty much had zero problems with drone. Also, I could care less about CARB rules and my state does not abide by them anyway. I mean I already have one cat and I don't need another.

 

Delete the second cat. there is no need for it. if the car is not looking for it, no one else will. but i do recommend a aftermarket system in place of the stock one. this one bolts up and sounds great for a good price from a swell company. it's always better to spend money once than twice.