Making Performance Exhaust Quieter?

[Pablito1702]

Thinking about trying to quiet down my BMW performance exhaust. Installed almost immediately after purchasing 2009 135i along with PPK, so I can't really recall how quiet the stock system was.

While I appeciate the more sporty sound under acceleration and downshifts, most of my drivng is freeway cruising at 75-80 mph and I think the exhaust is contributing some excess noise to the cabin. I am considering:

1) Trying combination of stock mid-pipe (with resonator) with performance muffler. Anybody else try this? Hopefully I wouldn't need to cut midpipe (in order to preserve option 2).

2) Going back to stock and selling performance exhaust.

3) Other suggestions from forum? Thanks!

[ScarecrowBoat]

I would say just go back to stock...

[escobar929]

if you have the BMWP exhaust, then your mid pipe is already cut, so no need to worry about that. So the first thing would be to swap out the BMWP y-pipe for the OEM resonator, see if that help. After that, stock is your only option

[SiN55]

OMG, what did you expected in the first place?

[ScarecrowBoat]

Originally Posted by SiN55

OMG, what did you expected in the first place?

[L8*Apex]

Originally Posted by Pablito1702

Thinking about trying to quiet down my BMW performance exhaust. Installed almost immediately after purchasing 2009 135i along with PPK, so I can't really recall how quiet the stock system was.

While I appeciate the more sporty sound under acceleration and downshifts, most of my drivng is freeway cruising at 75-80 mph and I think the exhaust is contributing some excess noise to the cabin. I am considering:

1) Trying combination of stock mid-pipe (with resonator) with performance muffler. Anybody else try this? Hopefully I wouldn't need to cut midpipe (in order to preserve option 2).

2) Going back to stock and selling performance exhaust.

3) Other suggestions from forum? Thanks!

I suggest you go back to stock and sell me your performance exhaust. Dibs???

[Red135]

If you think that the BMW Perf exhaust contributes excess cabin noise, then a stock exhaust is your only option.

[miro2296]

Originally Posted by L8*Apex

I suggest you go back to stock and sell me your performance exhaust. Dibs???

lol yes this!

[Dackelone]

Originally Posted by escobar929

if you have the BMWP exhaust, then your mid pipe is already cut, so no need to worry about that. So the first thing would be to swap out the BMWP y-pipe for the OEM resonator, see if that help. After that, stock is your only option

+1. I would take off that y-pipe that deletes the mid pipe's resonator and use the mid pipes w/rear resonator (OE).

Or... remove the rear PE muffler/can and put on the OE rear muffler. That might be more easy to do yourself or with the help of a friend. This should really quiet things down.

Or... go 100% back to stock.


Of course it is possible that something is wrong with your PE exhaust. Maybe some part of the exhaust is touching the car's body and causing the loudness. ?

Also... IF you have the latest SW update... (w/the new DSC icon (skidding car not the yellow circle arrow) and TPMS icon that points to a low tire) that makes the exhaust a tad bit louder under cruising conditions. Say 45 mph to 70 mph - I notice my car is much louder than before. I suspect that the new SW messes around with that flapper in the rear of the exhaust. But the PE system does not have that flapper system.


PE Y-Pipe (resonator delete)


mid pipe resonator (this is what gets deleted with the PE)


PE exhaust system...


stock exhaust left - PE right

[seslait]

Originally Posted by SiN55

OMG, what did you expected in the first place?

[1NNO_35]

This forum is getting from bad to joke...

[ilikebmxbikes]

I would go back to stock and sell the performance exhaust. The Axel back is very similar (or the same) the difference is really in the Y pipe.

[Makkasteez]

just sell it to me :]

[ScarecrowBoat]

I'm interested in the midpipe if you decide to sell...pm me

[Dackelone]

Go test drive a stock(N54) 135i. Not a N55 becuase those cars have a MUCH louder exhaust note.

It sounds like you need to go 100% back to stock. It will be much less raspy and quieter overall. One mans growl is anothers raspyness.

Btw... is your air filter stock (drop in filter) or have you changed out the air box to one of those dual cone air filters? That will also increase the sounds of the engine. ???


Dackel

[Pablito1702]

No change to air box, the only other mod is the PPK. Don't get wrong, I think the PE has a great sound in general. I am just trying to quiet down the cabin at 80+ mph freeway cruising because I spend a lot of time on the road. Frankly, I cannot really tell if the exhaust is contributing significantly to the noise at cruise as at this speed the engine is pretty much loafing. Maybe it is the result of the engine/turbo.

[Dackelone]

I bet your tires are making more noise than your exhaust. Mine RFT's were making some noise at 14K miles. So glad I replaced them with non RFT's. Just a thought - tires.

[RobM23]

Stock :/

[N55_BBM]

Had the same problem. Couldn't deal with the drone at ~2k rpm.

Slapped the resonator back on and left the PE muffler. Sounds exactly like I want it to now. Highly recommend it and know of other members in here who did it and were very happy as well.

[BerkTechnology]

1) Trying combination of stock mid-pipe (with resonator) with performance muffler. Anybody else try this? Hopefully I wouldn't need to cut midpipe (in order to preserve option 2).

This is your only other option if you want to keep the system. Of all the performance exhaust systems out there the BMWPE is one of the quietest if not the quietest system.

[tracer bullet]

I'm going to throw in that the OP should check for leaks.

I bought my car used and it had the PE already on it. I'm glad it's there, I love it, it helped me to choose that particular car F/S over the others. That said - the installation of the exhaust was lacking. Over the last few days mine slowly got louder. I couldn't figure if it was my imagination or not, so I checked last night. Sure enough one of those clamps had worked it's way back and one of the PE pipes was no longer connected to the rest of the system.

Looking at it, when "they" cut the factory exhaust they cut too much of it. Instead of the clamp sealing up the two pipes together it's also trying to bridge about a 1" gap as well. Not surprisingly it doesn't get the grip it needs to stay in place. I loosened it, slid it up, and tightened it back down but I'm not optimistic it will hold. I predict a trip to a muffler shop in my future to get something more robust.

Anyhow - OP may simply have a leak. It's pretty quiet when it's connected.

[Pol]

Originally Posted by Pablito1702

I cannot really tell if the exhaust is contributing significantly to the noise at cruise as at this speed the engine is pretty much loafing.

For sure it is..