[joshua12334]

Here's my idea to modify the OEM M2 Exhaust to M2 MPE. The goal is to keep the exhaust nice and quiet but also have the ability to loud. The yellow circles are the OEM exhaust valve.


M2 Hybrid exhaust, HOW IT WORKS?:
when it's in comfort/eco modem, the valves remained closed, exhaust soundwaves and gases go through the muffler.
When it's switched to Sport / Sport+ mode, the valves open up, exhaust soundwaves and gases go through the muffler and outer tips, a straight piped design just like the MPE.

Do you think this is a good design to accomplish the goal that's mentioned above? Are the valves located at the right location (Closer to the Y pipe? Closer to the tips?)

[thejeremyman9]

Have you seen this thread?

https://f30.bimmerpost.com/forums/sh...d.php?t=819125

I know the M2 OEM exhaust is different, but modifying the muffler internally might be easier than what you are showing. How are you going to get an extra valve and how are you going to integrate it into the new pipes you are proposing to add? The fab might be fairly complicated.

You could also just consider adding a electric cutout that you control manually.

[joshua12334]

Originally Posted by thejeremyman9

Have you seen this thread?

https://f30.bimmerpost.com/forums/sh...d.php?t=819125

I know the M2 OEM exhaust is different, but modifying the muffler internally might be easier than what you are showing. How are you going to get an extra valve and how are you going to integrate it into the new pipes you are proposing to add? The fab might be fairly complicated.

You could also just consider adding a electric cutout that you control manually.

Originally Posted by cfanb8

The goal is to keep the exhaust nice and quiet but also have the ability to loud.

Yes i have seen the m2 OEM exhuast mod. It's pretty loud IMO. Also electric cut out is kind of getto in a way.

[thejeremyman9]

Originally Posted by cfanb8

Yes i have seen the m2 OEM exhuast mod. It's pretty loud IMO. Also electric cut out is kind of getto in a way.

I just took another look at your sketch. What you proposed will basically make the flaps-closed sound be what the flaps-open sound is on the stock exhaust. So your comfort mode sound with the revision would sound like sport mode prior to the revision (both sides of OEM muffler would be used.

Also, are you sure your MPE sketch is correct? It doesnt really make sense because the muffler would basically be bypassed all the time.

To acheive what you are looking for, i think you need to do what i showed in my revised sketch. You just add a new valve that serves as a bypass for the muffler. The original value remains in place. Meaning when valve is closed, there is zero change from what you have right now. But when valve is open, you will have your current valve open function (open other side of muffler) + you will add the muffler bypass.

[joshua12334]

Originally Posted by thejeremyman9

Also, are you sure your MPE sketch is correct? It doesnt really make sense because the muffler would basically be bypassed all the time.

I have been having a hard time understanding how they designed the M2 MPE. Looks at the following pics, the inner pipes does look like a 1/2 straight pipe and half plumb back into the muffler, but then where do the gases go after it enters the muffler?

[joshua12334]

Originally Posted by thejeremyman9

I just took another look at your sketch. What you proposed will basically make the flaps-closed sound be what the flaps-open sound is on the stock exhaust.

Yes, there will not be any valves on the inner pipes, it will just be like and sound like sport+ because that's when the valve is opened on the oem exhaust. But even when the valves are opened, it's pretty quiet, just perfect for daily driving.

[Logicoeur]

Originally Posted by cfanb8

I have been having a hard time understanding how they designed the M2 MPE. Looks at the following pics, the inner pipes does look like a 1/2 straight pipe and half plumb back into the muffler, but then where do the gases go after it enters the muffler?

Some entered the canister, bounce around and exit either side. Because of the way the cylinders fire I believe there will still be some offset between pressure waves in the exhaust allowing the entering and exiting either side from the canister almost simultaneously