S55 M3/4 Prototype BMS exhaust photo, video and dyno - PRODUCTION VERSION PICS!!

[mike@x-ph.com]

Originally Posted by EyeWin

Hey Mr Mike, will the bms exhaust bolt up directly to an active autowerke dp?

Yes

[EyeWin]

Originally Posted by mike@x-ph.com

Yes

Thank you, sir!

[mike@x-ph.com]

Originally Posted by EyeWin

Thank you, sir!

My pleasure

[gregyoung14]

Just ordered one of these and had it installed on my 15' M4. I have stock downpipes at the moment. Right now, cold start-warm up is stupidly loud/deep/drone-y. Even after the car warms up, in sports plus/sport/efficient anything from 1-3k RPM sounds very deep/loud/drone-y it almost feels like it's making the interior rattle? Only other mod is BMS Stage 1 piggyback.

Would catless downpipes help reduce drone/vibration? Could it also help make the note sound less deep/farty and higher/mechanical?

Also, I haven't removed active sound yet, and I have a feeling it's piping an obnoxious amount of extra noise into the cabin, hard to say what's what, but that's on its way out.

Previous car was a 09' 135i vrsf downpipes berk street mids/cat back and it was loud, droned a bit around 2k RPM, but was very reasonable.

[Irishace]

Originally Posted by gregyoung14

Just ordered one of these and had it installed on my 15' M4. I have stock downpipes at the moment. Right now, cold start-warm up is stupidly loud/deep/drone-y. Even after the car warms up, in sports plus/sport/efficient anything from 1-3k RPM sounds very deep/loud/drone-y it almost feels like it's making the interior rattle? Only other mod is BMS Stage 1 piggyback.

Would catless downpipes help reduce drone/vibration? Could it also help make the note sound less deep/farty and higher/mechanical?

Also, I haven't removed active sound yet, and I have a feeling it's piping an obnoxious amount of extra noise into the cabin, hard to say what's what, but that's on its way out.

Previous car was a 09' 135i vrsf downpipes berk street mids/cat back and it was loud, droned a bit around 2k RPM, but was very reasonable.

Catless DPs make it way worse. The car became un-driveable for me. You need to add another resonator to the exhaust.

[gregyoung14]

Originally Posted by Irishace

Catless DPs make it way worse. The car became un-driveable for me. You need to add another resonator to the exhaust.

Did you have Catless DPs with this exhaust setup? I'm getting used to the sound, it's really not bad once the car is warmed up but quick drives when the car is cold down to the store for food and back, it's pretty loud.

The car want's to burble but the DP's are holding it back, I almost want to try and see what the verdict with DP's is for a few weeks, worst case sell them and throw OEM DP's back on. Or am I totally crazy and it'll deft. be way to loud? Funny enough, the BMS vids on youtube sound great but give you no perspective for just how loud/deep it is.