This is my first posting on the forum. I'm in the UK and I've been following this great forum for a while and bought a Countryman Cooper S just over a week ago.

I've immediately installed a Westfalia detachable towbar to tow my Rotax Max go kart on a small trailer. Whilst I was doing the job, I took a good look at the OEM exhaust with a view to gutting the OEM silencers to improve flow and increase power/torque. I've previously done this to other BMW cars with OEM stainless steel mufflers with great success. Before I do this to my Countryman, I'm wondering if anyone has previously done this on a Countryman Cooper S? Can anyone direct me to any photographs showing the internal layout of the OEM muffler so that I can make the neatest cuts? Is the muffler of single or double skin construction and is it of thick enough gauge to reweld easily?

Thanks in advance for any help and advice anyone can give me.

 

Hello,


OEM US muffler looks like For Countryman All4

 

The part number for the US Countryman Cooper S All4 is the same as my Euro spec Cooper S. What I'm wanting to see is a photo showing inside of the muffler when it's been cut open to show the internal pipe layout.

To achieve "silencing" the manufacturers use a layout that creates "reverse flow" inside the muffler, and what I do is remove some of the internal pipework so that the exhaust flow is more direct between the inlet and outlet pipes, but done in a way that doesn't make the car sound unduly noisy. Doing this mod costs me nothing except my time.

I use ECU datalogging to check the before and after performances after "gutting" the mufflers and I've been able to get up to 9% improvement in torque/hp from doing this with a couple of different normally-aspirated 6 cylinder BMW engines. I'm interested to see what gains I'd get with the turbo engine in the Cooper S.

 

Ah, you want an inside shot. I dont have that. Might have to dig into one.

 

I'd really appreciate it if you can find an inside shot and if you could tell me how thick the skin of the muffler is.

 

great post! i look forward to anymore info you can share

 

Hope someone has this shot, as I am very interested to see how this thread progresses.

 

 

I never found a shot of the R60 specific exhaust. But if anyone came across one that would be great.

 

I'm familiar with said mod! (I had some fun with an m3 I used to own: http://www.m3post.com/forums/showthread.php?t=253661 )
As its BMW sourced, its likely double walled like the BMW's, but perhaps not since they probably want to save weight. I'd expect a few different chambers in there, likely a helmholtz in there somewhere. I'd cut on top or back the tip side first and see whats there. You could always drill an inspection hole to see if you hit metal threads/baffle material.

I'm keeping my eye out for a used JWC r52 exhaust.. I'd like to see what a valve would do on this little mini..