I modified an ALTA R53 (MCS) catback to fit my R50 (MC) a while back and I'm VERY glad I did! I also just posted a bit about it in the ALTA feedback thread (here), but I'll paste the words below so we can keep any MC-specific comments (if there are any) here in this forum.
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This is a loooooong overdue post.....sorry for the delay Adam, Ken, et al.

Many moons ago (may be a couple years ago) I contacted ALTA about the possibility of them producing a version of their R53 catback for the R50. There were no plans to do so, but they seemed intrigued by my interest. I said I thought the single-sided MCS exhaust would fit an MC with just a few mods at the rear of the vehicle and offered to do it myself and report back with results.....again, sorry it took so long, but here ya go.

I LOVE IT! The sound even attracted attention at the recent Phil Wicks event at VIR.....one MCS owner wanted to know why my MC sounded better than the rest of the cars out there. Opinions are subjective, of course, but you get the idea. I think ALTA's description "The exhaust note is pleasant and lively at idle while giving a sporty, throaty growl under hard acceleration. All of this without annoying resonances at high idle or while cruising the interstate!" is spot on!

I tried a few MC exhausts and was unhappy with most of them -- mostly due to sound quality or quantity and in-cabin resonance -- and then I realized there are a number of single-sided MCS exhausts that were probably more thought out than those I figure are built mostly as an afterthought for the MC. The R50 and R53 use the same manifold and their exhausts use the same center tunnel and the same central hangers/mounting points. The passenger side can on an R53 (or the single rear can on single-sided R53 exhausts) sits exactly where the R50 rear can sits. The only things I had to do were 1) modify the hangers for the rear can and 2) cut off the S-shaped tail pipe (which routes the exhaust to the R53 center exit) and weld on a much shorter tail pipe and a tip to exit through the opening in the rear apron of my R50.

The fit is great! The sound is great! It weighs less than it did before I cut off the longer tail pipe!

Thanks ALTA!

 

Very Cool, would love to hear it and see pics.

 

 

Yeah, unfortunately I never think of pictures when it's up on the rack, etc. I promise to take a few when I have it in the air to evaluate the header project next week, and I'll see if I can post a video/audio clip. In the meantime, I found these on the hard drive -- they'll have to do for now.



Leftovers - gorgeous, but useless (to me). [edit: it's also sold]

 

Thanks for publishing those pics! Very helpful! Nice project as well!

 

love to see what it looks like from under the car
what were the costs with welds and all
what'd you pick for the tip

 

There's a video clip here now. It's just a stationary, with start, some idle, revs up to around 2K, 3K, 4K and 6K and a few blips after.
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edit: I moved the clip to blip.tv to free up my gallery space

 

I have been thinking about doing this for years! I was a little scared to spend the money and then have it fail misserably . Im so glad someone else took the jump and did it. It turned out great it seems. Looks and sounds awesome good job I am kindof excited now because i think im gonna give it a shot . Hope you dont mind if i shoot you some quick questions later.

 

sounds Hot!

 

Fire away!

 

The beauty part is that just blipping the throttle in the driveway sounds good, but in gear and pulling hard out on the road is even better. Plus, with the throttle well open and the revs climbing the intake starts to growl as well, and it's a great tonal match.

 

HAHAHA ok great.
THANKS!
You'll be hearing from shortly

 

Here are a couple things I've told others who've pm'd questions.

I have the m7 USS. It's known to cause a slight -- but annoying -- problem for some catbacks. One of its bars crosses under the car in an unfortunate spot and some catbacks, usually while lugging at very low revs (like from a standing start), can rattle just a bit against the USS. I don't remember which other catbacks, but this one does it from time to time on my car. I'm thinking about replacing part of the m7 USS with the TSW X-brace, but I only have this problem when I make an inelegant start.

As I said before, once you cut the tail pipe the thing fits perfectly, but needs two fixes -- a hanger mod for the rear can and a new tailpipe and tip. These two things aren't especially difficult, but the tailpie bit is definitely beyond the range of some shops. I made the mistake of going to a shop that sounded good, but cobbled up the tailpipe section (it was ugly and restrictive) and I had to have it re-done. The problem is, it requires fairly tight mandrel bends and a bit of skill with a welder. If you decide to do this, you want to get it right the first time, so check out the shop before hand.

1) Make sure they use mandrel bends in stainless and have the proper equipment to weld stainless.

2) Ask them if you can see a sample of their work (I think pics work, but whatever makes you comfortable). The best option IMO is a place that has at least one guy with the skill to fabricate stainless headers -- if they can do that, they can easily fab a clean tailpipe! Tell them you expect quality work that will not impede flow. I'm probably overemphasizing this, but when it comes to this sort of thing, anything less than "right" is wrong, and I know how disappointed I was with the first attempt. When I get the car up on the lift next Thu I'll snap some pics and then post the before and after.....plus the "after" shot might be good to take to your potential shop to show what needs to be done.....and the "before" shot to show them what might make you fly off in a fit of rage.....

3) Don't cut the tailpipe yourself - leave it to the fabricator to decide how much of the original pipe he needs/wants to work with.

 

WOW.... great advice and information....more than i planned to ask and good thing. I didnt think about some of the small things. Thank you so much! There is a place here that services only "little" british cars including ours. He does a bang up job on everything so i think i may have him to do the cutting and welding...and that way i can get my hands dirty and help him

I have really been wanting to get the new stealth alta cat-back. the thing is i will end up losing the tips with the cutting. Im gonna see if i can very carfully cut the tips so i can keep the stealth color. Also im may have to find some black pipe for the new part that will be goin in... thats gonnna be tough
Again thanks a ton. Your a big help and i will be keeping in touch with you to let you know how its going with progress pics and what not.

Also its cool to see someone who loves there first gen older model JPC and keeps it ALIVE!

Oh and i cant wait to see your under pics and your right, that will help me TON.

 

Yup, 6 years on and I'm no where near tired of this Cooper -- more fun all the time.

That stealth look is exactly what I would do if I could make it work (I'm still slowly deleting chrome elsewhere). I may "stealth"" the one I have.

I don't think there's any way to make the ALTA stealth tips fit. For one thing, they're probably too wide without cutting your bumper apron. Also, the angles may be all wrong.....hold that thought until I put up some pics from underneath.

I wouldn't worry too much about the black pipe. Better pics will make it clearer, but you don't see much of anything but the tip. This is one of the reasons I picked the ALTA -- it tucks well up under the car so the can and pipes are almost unseen.

 

WOW you got me beat...only 4 short years and i havent even scratched the surfface yet!

Yeah im not a big fan of chrome either, thats why i just replaced my orginal bumper with one from an '05 S. I didnt like those big knoby chrome things on it..gag. Now all i need is a new back bumper and ill be set Im sure you could have yours powdercoated, shouldnt cost to much; just as long as its not on it while they do it that would not go well. But have it sand blasted and take it to a rim shop. That would prob comeout nice with a flatt black ya know?

I was thinking about cutting and using only one of the two tips if at alll possible. But the angles...hmm didnt think about that. But i could just seperate and use one it may work.

Pictures will be neat, im interested to see what it looks like. yeah i dont like exhaust that hang down ie the magnaflow can...aghh! nightmare. No offense to those who baught it, just not my cup of tea. But thanks for all the advice. "what a pal, what a pal what a pal" - who first said that...some mobster on lonnie toons is the one i remember.

 

That is one hot sounding exhaust you got there!!!! I love it!!! Made props for thinking outside the box!!!

 

Thanks! I'm not the only Cooper owner to think of using an S exhaust, but I don't imagine scores have actually done it. Plus, I may be one of the first to use an ALTA? I don't remember exactly when/why I decided to do it.....may have been while trolling through the MCS exhaust thread one day to confirm my suspicion the MCS crowd was being offered more than those of us with "lowly" Coopers.....they are, no surprise here. Simple reason: there's more demand for S parts and, since development and production (etc) are expensive, supply follows demand. Of course any aftermarket producer has to be happy when he comes up with a crossover part that can be used on more than one model, and since the cars use a lot of interchangeable stock parts, there are plenty of interchangeable aftermarket opportunities.

The exhaust looks (on the surface) like it's NOT one of those interchangeable things. However, it seems to me like a manufacturer developing a single-sided S exhaust has a relatively cheap development and production path to a good non-S exhaust, especially if they have that in mind from the start. This one is a good example. The mid-pipe is 100% interchangeable and the rear section can be almost identical, using most of the same jigs and parts.....and the tail pipe section would be easier to make and use less materials, plus the single tip has to be cheaper and a lot easier to align, etc.

Oh well, since there isn't an ALTA non-S exhaust on the market, I guess that makes mine pretty unique.

 

I had the MINI up on a lift to evaluate my header project (should get that done next week ). I also had them change the tip for me -- wanted to try a different look. Anyway, I took a few pics to show the new, improved tailpipe section, so here are the before (WARNING: not for weak stomachs! ) and after shots.

But first..... I already know my car is dirty -- I'm already embarassed to post pics of my dirty car -- no need to tell me to "wash your car."

As you can see, I didn't have this fixed right away...thus the rust...purty ain't it?




I know, photography isn't my strong suit.


See the hole in the apron? It was cooked through by one of those other MC exhausts I tried. I have a new apron waiting in the garage but didn't want to replace this one until I figured I was done messing with the exhaust. Here you get a lovely glimpse of the internal view. Quality work from HP Racing!

Now we move on to the good stuff thanks to a real exhaust artist at Induktion Motorsports of Hanover, MD.


Here it is today after they put on the new tip.

 

Wow, that sounds fantastic! Not to go too far OT here but who are you going to use for a header?

 

OBX, cleaned up a bit and coated.

 

You were right those before pictures were sickening , but those after.... THEY LOOK GREAT!!! Those people did a superb job. Thanks for the pics too, they will realyl help me with my project. COngrats on the new look, oh yeah the Tip looks good too.

 

Thanks! I'm gonna have the same guys build my cat pipe and install the header next week.