[Markos ZimZimma]

I do really like the sound of my 2015 335i F31, although with windows closed it's a touch too quiet perhaps, hence me thinking about the MPE which is just a back box it seems rather than a whole system. I'm definitely not looking to do any other mods to the car such as remapping or downpipes etc, so I'm wondering if anyone has heard a standalone MPE on a 335i in person and for their thoughts on it. Online it seems it's a slight improvement over stock but nothing too wild, which probably sounds like what I'm after. Any thoughts appreciated!

[AlwynMike]

If your current system is valved, the MPE may drone a bit at 60 and 70mph, especially when loaded up motorway hills.
My 440 MPE was awful when the caravan was behind; low revs and pulling hard made motorway cruising uncomfortable....although I did have the front box deleted too!
Ordinarily it was fine though.

[Markos ZimZimma]

Originally Posted by AlwynMike

If your current system is valved, the MPE may drone a bit at 60 and 70mph, especially when loaded up motorway hills.
My 440 MPE was awful when the caravan was behind; low revs and pulling hard made motorway cruising uncomfortable....although I did have the front box deleted too!
Ordinarily it was fine though.

Thanks for the info – I have a feeling the 440 MPE might be a little louder than the 335i one but still good to know. And yes, current standard system is valved. Did the drone improve over time? I once had drone on a custom exhaust which thankfully completely cleared up after a couple of thousand miles after sooting up a bit!

[Alscoob]

Think the MPE for the 335i is still valved? if so will be fine. This shows it but you would need to check.

https://www.realoem.com/bmw/enUS/sho...diagId=03_0059

The MPE for the 340/440i is not valved and as said above it drones when trying to cruse or under load when using the torque not the revs of the engine. So much so I sold mine after 2 weeks and just have the standard back box with valve permanently open & MPE tips. But the sound of a B58 is different to the N55 engine. The back box I bought was second hand but excellent condition and the drone was always there. Here you can see the 340/440i one as a comparison....

[AlwynMike]

Originally Posted by Markos ZimZimma

Did the drone improve over time? I once had drone on a custom exhaust which thankfully completely cleared up after a couple of thousand miles after sooting up a bit!

No. Same from day one, but I bought it second hand, so pre-sooted!

[Markos ZimZimma]

Originally Posted by Alscoob

Think the MPE for the 335i is still valved? if so will be fine. This shows it but you would need to check.

https://www.realoem.com/bmw/enUS/sho...diagId=03_0059

The MPE for the 340/440i is not valved and as said above it drones when trying to cruse or under load when using the torque not the revs of the engine. So much so I sold mine after 2 weeks and just have the standard back box with valve permanently open & MPE tips. But the sound of a B58 is different to the N55 engine. The back box I bought was second hand but excellent condition and the drone was always there. Here you can see the 340/440i one as a comparison....

Attachment 2865448

Attachment 2865450

Was the MPE bought used? Looks brand new! Have heard that the MPE for the 335i makes perhaps less of a difference than I'd like, so my next step is to pull the plug for the valve (whilst it's open) so the valve is permanently open and see how I get on with that I think. I've had a quick look under the car and I think there's a small tab that I need to pull up or push down for the plug to come out of mine, and lets see how much that improves things... Will look into back box mods after that as that seems to be a relatively common thing to do to them if a permanently open valve doesn't quite do it for me.

[Alscoob]

Originally Posted by Markos ZimZimma

Was the MPE bought used? Looks brand new!

Yes bought used but I cleaned it up to sell. Stainless steel exhausts should be shiney !!

Not sure on the 335i but on the x40i's you can get a plug for the connector when it's off the exhaust believe it stops it throwing a fault up. around £18 from BMW (18302411427 Dummy flap actuator for the x40i's) But maybe the electronics are different on yours and it's not needed.

[Markos ZimZimma]

Originally Posted by Alscoob

Yes bought used but I cleaned it up to sell. Stainless steel exhausts should be shiney !!

Not sure on the 335i but on the x40i's you can get a plug for the connector when it's off the exhaust believe it stops it throwing a fault up. around £18 from BMW (18302411427 Dummy flap actuator for the x40i's) But maybe the electronics are different on yours and it's not needed.

Thanks for this: I spotted that part number on another thread and I've just bought it

I'll give it a go when I get a friend over to get on the revs so the flap will be open when I unplug it - which should mean it then permanently stays in the open position, fingers crossed!