M135i Custom exhaust Question

[Holiman]

So i been looking to do a full/Custom Exhaust on my PWG M135i for a while now and have looked into different options. From MPE to muffler delete options to full exhausts. I Currently only have a DP. I then realised that i do not want to delete the muffler all together because i fear droning. (So custom y pipe with no muffler has gone out the window). The other factor for me is price so i had to factor that in into this whole exercise.

Which leads me to the following...

So i have been thinking of doing the below mod:

http://f30.bimmerpost.com/forums/showthread.php?t=819125&page=1

To summarise for those that will not go through the whole post, the above link is a modification of the standard box to close up the perforation in two of the tree chambers of the muffler to improve sound without affecting the middle chamber and thus not affecting drone.

And then welding the standard back box to a straight 75 mm pipe.

(i can get a spare box on the forum without cutting mine off the the current Exhaust)

Any thoughts on the above?

The obvious question is why not go for a full exhaust without the modification?

Like i mentioned price is a factor. I can get the back box for a good price and also the mid pipe for a good price. My only other expense will be labour. This is still around 4K cheaper than an exhaust...

 

[Kolbe]

So i been looking to do a full/Custom Exhaust on my PWG M135i for a while now and have looked into different options. From MPE to muffler delete options to full exhausts. I Currently only have a DP. I then realised that i do not want to delete the muffler all together because i fear droning. (So custom y pipe with no muffler has gone out the window). The other factor for me is price so i had to factor that in into this whole exercise.

Which leads me to the following...

So i have been thinking of doing the below mod:

http://f30.bimmerpost.com/forums/showthread.php?t=819125&page=1

To summarise for those that will not go through the whole post, the above link is a modification of the standard box to close up the perforation in two of the tree chambers of the muffler to improve sound without affecting the middle chamber and thus not affecting drone.

And then welding the standard back box to a straight 75 mm pipe.

(i can get a spare box on the forum without cutting mine off the the current Exhaust)

Any thoughts on the above?

The obvious question is why not go for a full exhaust without the modification?

Like i mentioned price is a factor. I can get the back box for a good price and also the mid pipe for a good price. My only other expense will be labour. This is still around 4K cheaper than an exhaust...

This should work. I had the M135i EWG with the MPE exhaust with Supersprint downpipe. Very loud at cold start but lovely sound once warm. No drone. When I checked inside the MPE the difference to the stock silencer was that there were no perforated tubes as far as I could see. As long as you don't change the pipe going into the Helmholtz chamber you should have no drone. Also, reuse the packing material - even though the holes are welded up. Good luck!