Best way to attach 2.5" exhaust to OEM 60mm muffler piping?

Zasquatch · 11-03-2011, 07:47 AM

I have a Billy Boat DP-Muffler center section I got from a member and want to install it and retain my OEM mufflers ('07 e90), resulting in a completely cattless system. The exhaust is three sections, each of which is slip-fit and clamp-on, except for the DP flanges of course.

What is the easiest way to attach the end of the center section which is 2.5" SS piping to the OEM 60mm OD (2.36") muffler pipe? I was hoping to do the install myself, but if welding is the only way they I will have to go to a shop.

Thanks for the help... I've never "constructed" my own exhaust before, always done full bolton systems..

Tzu · 11-03-2011, 09:09 AM

Are they radial pressure clamps or v-band clamps?

IMO, i'd cut off the stock mufflers at the point where your aftermarket section meets them, weld on identical flanges to your aftermarket center section and do the same to the opposing flange on the stock center section. Then you can swap back and forth as need be. Probably a little more work than you wanted, but the interchangability is nice.

Zasquatch · 11-03-2011, 02:19 PM

Quote:

Originally Posted by Tzu

Are they radial pressure clamps or v-band clamps?

IMO, i'd cut off the stock mufflers at the point where your aftermarket section meets them, weld on identical flanges to your aftermarket center section and do the same to the opposing flange on the stock center section. Then you can swap back and forth as need be. Probably a little more work than you wanted, but the interchangability is nice.

One side is 2.5" ID and one is 2.5" OD (I'm guessing) with slits on each end and a band clamp that tightens the joint. The aft end of pipe is just a plain end with no slit. My guess is that this will be a tight fit -or close to it- over the 60mm OD muffler pipe (after being cut from the rest of the exhaust).

I will prob just get it welded but I was hoping for something easy, like the reduction sleeve clamps that I've seen online.

scalbert · 11-03-2011, 02:30 PM

It may take some “persuasion” but most of the time the 60mm stock tubing will slip into the 2.5 inch pipe. It just depends on the wall thicknesses. Sometimes it is too tight and a little grinding/sanding gets it done. Some very thin walled 2.5 inch will be loose.

Tzu · 11-03-2011, 02:36 PM

You can by all means get clamps. You can also get the stock muffler piping stretched a few mm, no problem.

I always perferred a nice, solid weld. Maybe I'm bias.

Zasquatch · 11-04-2011, 07:39 AM

Cool, thanks for the input guys.

11-03-2011, 07:47 AM	#1
Zasquatch Captain 36 Rep 708 Posts Drives: '07 BMW 335i Join Date: Sep 2010 Location: CT iTrader: (15) Garage List 2007 BMW 335i [0.00]	Best way to attach 2.5" exhaust to OEM 60mm muffler piping? I have a Billy Boat DP-Muffler center section I got from a member and want to install it and retain my OEM mufflers ('07 e90), resulting in a completely cattless system. The exhaust is three sections, each of which is slip-fit and clamp-on, except for the DP flanges of course. What is the easiest way to attach the end of the center section which is 2.5" SS piping to the OEM 60mm OD (2.36") muffler pipe? I was hoping to do the install myself, but if welding is the only way they I will have to go to a shop. Thanks for the help... I've never "constructed" my own exhaust before, always done full bolton systems..
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11-03-2011, 09:09 AM	#2
Tzu Lieutenant Colonel 29 Rep 1,551 Posts Drives: 335i Join Date: Jun 2010 Location: Toronto iTrader: (1)	Are they radial pressure clamps or v-band clamps? IMO, i'd cut off the stock mufflers at the point where your aftermarket section meets them, weld on identical flanges to your aftermarket center section and do the same to the opposing flange on the stock center section. Then you can swap back and forth as need be. Probably a little more work than you wanted, but the interchangability is nice.
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11-03-2011, 02:30 PM	#4
scalbert Major General 153 Rep 5,780 Posts Drives: '13 S4, '15 Q7 Join Date: Feb 2007 Location: Woodstock, GA iTrader: (8)	It may take some “persuasion” but most of the time the 60mm stock tubing will slip into the 2.5 inch pipe. It just depends on the wall thicknesses. Sometimes it is too tight and a little grinding/sanding gets it done. Some very thin walled 2.5 inch will be loose.
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11-03-2011, 02:36 PM	#5
Tzu Lieutenant Colonel 29 Rep 1,551 Posts Drives: 335i Join Date: Jun 2010 Location: Toronto iTrader: (1)	You can by all means get clamps. You can also get the stock muffler piping stretched a few mm, no problem. I always perferred a nice, solid weld. Maybe I'm bias.
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11-04-2011, 07:39 AM	#6
Zasquatch Captain 36 Rep 708 Posts Drives: '07 BMW 335i Join Date: Sep 2010 Location: CT iTrader: (15) Garage List 2007 BMW 335i [0.00]	Cool, thanks for the input guys.
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