Author Topic: Antone Else's SuperSprint Rub the Rear Apron??? (Read 2914 times)

bmwman91 · « **on:** March 26, 2009, 01:39:31 AM »

I finally put my car back together tonight, and I installed my new SuperSprint cat back. It is the newer 2-piece one (I previously had the 1 piece unit in there but it was time for anew one). Well, try as I might I cannot get it to stop sitting against the rear apron. I thought I fixed it by bending the muffler hangers a little, but abour 5 minutes down the road I could hear it making awful noise.

Anyone else have this issue? I am trying to think if there would be a way to bend the pipe or something. It is particularly sensitive to how tightly I have the flange at the cat torqued. The cat is an aftermarket one that was welded in, so perhaps it was not well aligned previously. Perhaps I should go there & have them cut & re-weld that bit so that it sits properly without forcing the downpipe into a weird position (= cracks in header). Dammit! I just swapped all of the poly bushings for rubber to make the car quieter!!!

txleadfoot · « **Reply #1 on:** March 26, 2009, 08:23:56 AM »

My SuperSprint used to do that, even with new rubber hangers installed. I took it to a local indy muffler shop. All they did was heat up (red-hot) the portion of the pipe just ahead of the muffler and use a big-ass pry bar stuck inside the muffler to bend it away from the valence.

JP 91iS · « **Reply #2 on:** March 26, 2009, 10:58:55 AM »

Mine is roughly 1-3 mm away from my rear apron and I was worried about rubbing- but so far haven't noticed anything. When its just sitting I tried wiggling it around and its really stiff so I don't think I'll have any issues.

As far as why yours is making contact, sounds reasonable to suspect the aftermarket cat. You may try rotating the pipe piece of the supersprint since it seems like there is room for play there. You could also adjust how far the muffler piece sticks onto the pipe piece. The tip angles up off the back of the muffler so you may just need to pull it out an inch.

bmwman91 · « **Reply #3 on:** March 26, 2009, 01:33:13 PM »

Thanks guys! I am going to a local muffler shop after lunch to see if they can cut & re-weld the cat in, in such a way that it is not forcing the cat-back into a weird position. I will try to shy away from having the hangers pull on the muffler itself as I suppose this will put undue stress on the header.

ak96ss · « **Reply #4 on:** March 26, 2009, 03:09:53 PM »

My exceedingly expensive B&B Triflo does the same thing, as did the stock replacement Eberspacher I bought from BavAuto that the Triflo replaced, both with an OE cat on there no less. I took it in several times, and finally just ended up widening the 'notch' where the pipe comes out. Unless you look *very* carefully, it is not noticeable, and I have no more problems with the pipe striking the valance.

One thing I mean to check one day is the motor mounts - I have heard that a worn motor mount can show itself as the exhaust pipe not aligning properly at the very end. Seems plausible...

bmwman91 · « **Reply #5 on:** March 27, 2009, 12:29:29 AM »

Well, the issue is 100% fixed. I took it to a local muffler shop & had them cut the pipe just behind the cat, and cut 90% of the way through in front of it. The muffler popped right into place, we bent the cat into place (it was held on by a little bit of pipe in front still), and then welded it all up again. Kick ass. Best $40 I ever spent.

twinpop171 · « **Reply #6 on:** March 27, 2009, 04:45:06 AM »

I had the same problem with mine. I ended up using small pieces of diamond plate aluminum as spacers between the top of the muffler and the hangers to massage the fit a little by pushing the muffler down.

A bit of Mickey Mouse mechanical work but it fits fine now with no rattles.

Dan