06-04-2014, 10:17 AM
I'm going to be doing the BMW performance exhaust mod tonight. The stock exhaust on the 135i's doesn't really cause any restrictions except the downpipes. So anything you modify past that is just for sound.
Having said that, BMW charges about $1000 for their performance exhaust. On the PE, the muffler is the same size and shape as the OEM one, so someone got the idea of looking inside one of these mufflers. Turns out, its the same thing as the OEM one minus the vacuum controlled exhaust valve and one pipe is solid instead of having holes in it to let the sound get muffled like the OEM one.
So, to save yourself a thousand bucks, you can cut open the OEM muffler and either weld those holes shut or just wrap it with a few layers of header wrap. All you need to do after that is weld the muffler case back together.
Actually, this is better than the BMW Performance Exhaust because you still retain the functionality of the factory exhaust valve if you want. While the exhaust valve being open or shut doesn't make a huge difference on the factory exhaust, it will on this because the pipe that is opening and closing is the one that is getting modified.
This means I can have a perfectly silent exhaust for long highway trips if I want and still have some exhaust sound otherwise.. Thanks to the tune I have I can open and close that exhaust valve at will using the steering wheel controls. :thumbup:
Hopefully this will hold me off on wanting to actually spend 500+ on an aftermarket exhaust system.
Having said that, BMW charges about $1000 for their performance exhaust. On the PE, the muffler is the same size and shape as the OEM one, so someone got the idea of looking inside one of these mufflers. Turns out, its the same thing as the OEM one minus the vacuum controlled exhaust valve and one pipe is solid instead of having holes in it to let the sound get muffled like the OEM one.
So, to save yourself a thousand bucks, you can cut open the OEM muffler and either weld those holes shut or just wrap it with a few layers of header wrap. All you need to do after that is weld the muffler case back together.
Actually, this is better than the BMW Performance Exhaust because you still retain the functionality of the factory exhaust valve if you want. While the exhaust valve being open or shut doesn't make a huge difference on the factory exhaust, it will on this because the pipe that is opening and closing is the one that is getting modified.
This means I can have a perfectly silent exhaust for long highway trips if I want and still have some exhaust sound otherwise.. Thanks to the tune I have I can open and close that exhaust valve at will using the steering wheel controls. :thumbup:
Hopefully this will hold me off on wanting to actually spend 500+ on an aftermarket exhaust system.
2015 VW GTI | 2007 4Runner Sport
SOLD
2010 Nissan 370z | 2003 BMW M3
2005 Subaru WRX | 2010 BMW 135i | 1999 BMW M3
2002 Pontiac Trans Am WS6 | 2006 Mitsubishi Evolution IX SE
1995 Pontiac Firebird Formula | 1998 Mitsubishi Eclipse GSX | 1996 Pontiac Firebird
SOLD
2010 Nissan 370z | 2003 BMW M3
2005 Subaru WRX | 2010 BMW 135i | 1999 BMW M3
2002 Pontiac Trans Am WS6 | 2006 Mitsubishi Evolution IX SE
1995 Pontiac Firebird Formula | 1998 Mitsubishi Eclipse GSX | 1996 Pontiac Firebird