1M exhaust drone problem

[VO1M]

Originally Posted by johnsfb

I’ve now been for a run with the other exhaust on and the drone is ALMOST completely gone. It now comes in about 200 rpm higher but compared to before, the difference is like chalk and cheese. I can get along with the way it is now.

Yes, the dealer put the one from the demo on mine and tested it, finding it to be ok.
They expected mine to cause problems on the demo but that didn’t happen so they had a quick fix although they don’t know how/why.

They also said that if mine did cause problems on the demo, it would have had to go back on my car and investigations started again from there, so I think I’m very lucky indeed.

I’m sorry this doesn’t help others who have this drone but the dealer said they have informed BMW about it because this was all warranty work.

With so many people getting this I would say there has to be some underlying problem though.

Now you've had more time in it with the new exhaust, I would appreciate your thoughts as to whether it definitely much better than it was. The reason I ask, is that mine feels better some days than others. Mind games!

It still doesn't make sense to me how the old faulty exhaust is OK on the demo car.

[rapter]

Originally Posted by VO1M

Now you've had more time in it with the new exhaust, I would appreciate your thoughts as to whether it definitely much better than it was. The reason I ask, is that mine feels better some days than others. Mind games!

It still doesn't make sense to me how the old faulty exhaust is OK on the demo car.

Yours now has an intermittent drone ?

[VO1M]

Originally Posted by rapter

Yours now has an intermittent drone ?

No it's not intermittent - more that the mind concentrates more on the drone some days than others. It seems to be better on normal roads than on motorways - probably because of the constant load on motorways.

[HP Autosport]

We may have a solution here...

http://www.1addicts.com/forums/showthread.php?t=535738

[Red135]

Harold, did you have the drone initially?

[rapter]

Originally Posted by HP Autowerks

We may have a solution here...

http://www.1addicts.com/forums/showthread.php?t=535738

Have you had the opportunity to cruise on the freeway (Highway) and experience no load "drone" ???

[HP Autosport]

Originally Posted by Red135

Harold, did you have the drone initially?

No, not really. There was some resonance, but not a drone. Not enough to bother me.

[HP Autosport]

Originally Posted by rapter

Have you had the opportunity to cruise on the freeway (Highway) and experience no load "drone" ???

No load drone?

Here is what I experienced after the mid-pipe install.

http://www.1addicts.com/forums/showp...0&postcount=11

[Red135]

Originally Posted by HP Autowerks

No, not really. There was some resonance, but not a drone. Not enough to bother me.

Then I guess we can't label it a possible solution.

[VO1M]

Has anyone had a definite answer from a BMW dealer as to what the problem/solution is?

[Red135]

Originally Posted by VO1M

Has anyone had a definite answer from a BMW dealer as to what the problem/solution is?

When I asked the question, the only response I received was that the dealership hadn't seen any service bulletins in regards to the drone.

[HP Autosport]

Originally Posted by Red135

Then I guess we can't label it a possible solution.

You said initially, did you mean with the oem exhaust? There was some resonance with the stock exhaust, but not with this mid-pipe.

[rapter]

Originally Posted by HP Autowerks

You said initially, did you mean with the oem exhaust? There was some resonance with the stock exhaust, but not with this mid-pipe.

The resonance that we are complaining about occurs on the highway in 6th between 2200rpm - 2800rpm. Did you experience a harmonic from the exhaust during these driving conditions?

Following the installation of the mid pipe does driving at this engine speeds in 6th produce a quiet or more quiet ride than it did in stock form?

[HP Autosport]

Originally Posted by rapter

The resonance that we are complaining about occurs on the highway in 6th between 2200rpm - 2800rpm. Did you experience a harmonic from the exhaust during these driving conditions?

Following the installation of the mid pipe does driving at this engine speeds in 6th produce a quiet or more quiet ride than it did in stock form?

There was hardly any resonance to start with and after the mid-pipe it got quieter in my opinion. There is just a bit at about 2300 rpm, none below or above it.

See post #74 or go to the link below:

http://www.1addicts.com/forums/showp...0&postcount=11

[rapter]

There is some in-car video from autoblog showing (amplifying) the exhaust drone in the car. The sounds that we are hearing is similar to this one when the in car video is playing. Note, the audio quality is really poor on the microphones so the Drone IS REALLY REALLY loud in this particular case. The more videos I see the more I think and feel that the exhaust drone is part of the vehicle and in no way is a design flaw.

HP AutoWorks, can you chime in and let us know if you are hearing similar droning in your car following your mid-pipe modification?

http://ca.autoblog.com/2011/05/26/bm...t-rs-on-track/

[Karen and John]

Hi,

We received our 1M on the 20 May and have now covered over 3000 km in it.

With respect to the exhaust drone, we have noticed it a bit too: interestingly, it seems to be very dependent on temperature, humidity and, in particular, road surface so to my mind there is definitely some sort of resonance issue with the exhaust mounts. For instance, it was noisy on UK roads, much better in Spain, then disappeared completely, returned after the car was cleaned at the 2000 km service, and is now not noticeable except when the road surface is broken.

I am not sure it is anything to worry too much about.

[Ascari]

The driving in this clip is not worthy of the car... Pretty messy.

Originally Posted by rapter

There is some in-car video from autoblog showing (amplifying) the exhaust drone in the car. The sounds that we are hearing is similar to this one when the in car video is playing. Note, the audio quality is really poor on the microphones so the Drone IS REALLY REALLY loud in this particular case. The more videos I see the more I think and feel that the exhaust drone is part of the vehicle and in no way is a design flaw.

HP AutoWorks, can you chime in and let us know if you are hearing similar droning in your car following your mid-pipe modification?

http://ca.autoblog.com/2011/05/26/bm...t-rs-on-track/

[rapter]

Originally Posted by Karen and John

Hi,

We received our 1M on the 20 May and have now covered over 3000 km in it.

With respect to the exhaust drone, we have noticed it a bit too: interestingly, it seems to be very dependent on temperature, humidity and, in particular, road surface so to my mind there is definitely some sort of resonance issue with the exhaust mounts. For instance, it was noisy on UK roads, much better in Spain, then disappeared completely, returned after the car was cleaned at the 2000 km service, and is now not noticeable except when the road surface is broken.

I am not sure it is anything to worry too much about.

My car makes the drone independent of what the road conditions are.

[Mark]

The drone is definitely there, but i'm coming from a car with a remus exhaust so it doesn't bother me much. However, I did find that the solution is to get to the highest gear possible and voila the drone usually disappears...

[HP Autosport]

For comparison we re-install the oem mid-pipe and find it to have more drone(it doesn't really bother me) than the aftermarket mid-pipe that replaces it. The oem mid-pipe also has slightly more drone at various rpm ranges where the aftermarket only seem to do it ever so slightly at one certain rpm only.

[rapter]

Originally Posted by HP Autowerks

For comparison we re-install the oem mid-pipe and find it to have more drone(it doesn't really bother me) than the aftermarket mid-pipe that replaces it. The oem mid-pipe also has more slightly more drone at various rpm ranges where the aftermarket only seem to do it ever so slightly at one certain rpm only.

Very interesting

Curious, are you selling your modification to the market?

Could you take some in car sound samples with both systems?

Question about your mid pipe system: essentially the system removes the two cats and replaces them with straight pipes?

[DrRay81]

Originally Posted by HP Autowerks

For comparison we re-install the oem mid-pipe and find it to have more drone(it doesn't really bother me) than the aftermarket mid-pipe that replaces it. The oem mid-pipe also has more slightly more drone at various rpm ranges where the aftermarket only seem to do it ever so slightly at one certain rpm only.

and CEL's with your mid pipe system? is a tune required? any performance gains that are noticeable? is it a straight forward bolt on with no modifications?