[SOLVED] 428 to 435 exhaust conversion now drone

tboooe · 09-24-2015, 08:53 PM

A while ago I successfully converted my 428 exhaust to a 435 one. Overall I am happy with it except I get an annoying drone between 1500 and 2000 rpm at around 40mph. Normally this doesn't bother me as I usually keep the rpms above 2000. However, when I am just driving casually around town the drone is bothersome.

Does anyone else who did this conversion experience any drone? Is there any solution? If it matters I used the OEM muffler clamp instead of welding it.

kirill_1361 · 09-26-2015, 09:07 PM

I did exactly the same conversion on my 328i. I read your thread and went to Mike's muffler shop to install the muffler. So everything is exactly the same, except I have N20 engine. I didn't have any drone for a first 500 miles. Then I disconnected the valve to make both pipes to be open all the time. That is where I started to notice the drone at around 40 mph. But I recently tuned the ECU on my car (didn't want to put any piggy box) and now I don't have any drone + the sound of the exhaust became meaner. I loved the sound with this muffler on the stock car but now it is totally different. Sounds more like a 335.

mge92 · 09-28-2015, 01:00 PM

ROBNYC

DG20 · 09-28-2015, 03:03 PM

I did this conversion and i left my valve unplugged and i never get drone

MattTheCarNut · 09-28-2015, 03:52 PM

My valve is plugged in and no drone.

What happens if I unplug it???

FSociety · 09-28-2015, 11:07 PM

Quote:

Originally Posted by MattTheCarNut

My valve is plugged in and no drone.

What happens if I unplug it???

Both valves remain open and you get more sound.
Although, not sure if the car needs to be on first and unplug the wire or if it needs to be off and then unplug.

tboooe · 09-29-2015, 11:52 AM

Quote:

Originally Posted by MattTheCarNut

My valve is plugged in and no drone.

What happens if I unplug it???

My valve is plugged in so I am not sure what the cause can be. To me the drone sounds like when a car is in too high of a gear for the speed, except that the sound is amplified and seems to resonate throughout the cabin. I guess that is the definition of drone?

I did use a 335 muffler though I understand its the same as the 435 one?

I am at a loss for what could be causing this.

tboooe · 09-29-2015, 04:06 PM

Finally got this drone issue solved! Here is what I did:

For this mod, I used the OEM muffler clamp to attach the muffler to the midpipe instead of welding. I did it this way so I could easily change back to the original 428 or other exhaust in the future. I got to thinking that perhaps the clamp or how it clamped the exhaust could have been what was causing the drone. When I looked at the exhaust more closely, specifically the exhaust tips, I noticed the muffler was rotated up so that the exhaust tips were horizontal, instead of slightly slanted downward as they are stock. The axis of rotation is around the two rubber vibration dampening pieces that the muffler attaches to. On the 335/435, you can see there is quite a bit of gap between the exhaust tip and the diffuser. In my case, there was hardly any gap. This caused the midpipe to be forced downward so that it sat dangerously close the frame cross brace. I am not sure the midpipe vibrated against the brace at certain RPMs causing the drone.

I loosened the clamp, rotated the muffler so that the exhaust tips pointed down slightly which in turn raised the mid pipe away from the frame cross brace. After taking the car for a test drive I can report the drone is gone!!! I am not sure if I am imaging things but I would swear that the car revs quicker from 1500-2000 RPMs now.

Anyway, if anyone has drone and used the muffler clamp it would be worth loosening it and readjusting the position of the midpipe. I hope this helps someone else.

F36 Pilot · 09-29-2015, 10:19 PM

That is great news! I know the drone would have bothered me too so I decided not to do the conversion after reading your original post about it. Now that you have fixed the problem and others who have done the conversion report no drone, I guess I'll be shopping for a 335/435 muffler.

tboooe · 09-30-2015, 08:14 AM

Quote:

Originally Posted by F36 Pilot

That is great news! I know the drone would have bothered me too so I decided not to do the conversion after reading your original post about it. Now that you have fixed the problem and others who have done the conversion report no drone, I guess I'll be shopping for a 335/435 muffler.

Go for it! I love the symmetry of the dual exhaust look. Now I need to get the M Perf diffuser.

perrystacks · 10-01-2015, 12:48 AM

i hear the same drone but i had my exhuast welded.. i am going to have to take a look at this again.

smithf80 · 10-02-2015, 12:25 PM

Quote:

Originally Posted by perrystacks

i hear the same drone but i had my exhuast welded.. i am going to have to take a look at this again.

That bad?

I think the drone he's describing isn't the normal small amount you hear when you get the 335i exhaust on the 328.

With my MPerf I only get a little, and I wouldn't even call it Drone so much as just engine noise.

Try a muffler delete, that drones, this is nothing haha.

zman1237 · 10-03-2015, 12:21 PM

Quote:

Originally Posted by tboooe

Finally got this drone issue solved! Here is what I did:

For this mod, I used the OEM muffler clamp to attach the muffler to the midpipe instead of welding. I did it this way so I could easily change back to the original 428 or other exhaust in the future. I got to thinking that perhaps the clamp or how it clamped the exhaust could have been what was causing the drone. When I looked at the exhaust more closely, specifically the exhaust tips, I noticed the muffler was rotated up so that the exhaust tips were horizontal, instead of slightly slanted downward as they are stock. The axis of rotation is around the two rubber vibration dampening pieces that the muffler attaches to. On the 335/435, you can see there is quite a bit of gap between the exhaust tip and the diffuser. In my case, there was hardly any gap. This caused the midpipe to be forced downward so that it sat dangerously close the frame cross brace. I am not sure the midpipe vibrated against the brace at certain RPMs causing the drone.

I loosened the clamp, rotated the muffler so that the exhaust tips pointed down slightly which in turn raised the mid pipe away from the frame cross brace. After taking the car for a test drive I can report the drone is gone!!! I am not sure if I am imaging things but I would swear that the car revs quicker from 1500-2000 RPMs now.

Anyway, if anyone has drone and used the muffler clamp it would be worth loosening it and readjusting the position of the midpipe. I hope this helps someone else.

Did you use the 335 or 428 muffler clamp? I have the 428 and I'm putting a 335 on it. Just don't know what muffler clamp I need.

tboooe · 10-03-2015, 02:37 PM

Quote:

Originally Posted by zman1237

Did you use the 335 or 428 muffler clamp? I have the 428 and I'm putting a 335 on it. Just don't know what muffler clamp I need.

I replied to your PM but you need a 75mm clamp. The BMW part # is 18307560781. You also need the muffler shop to make a transition piece of pipe from the 335 exhaust that will is 75mm to match your midpipe diameter. This is very easy and any decent exhaust shop can do this.

N26Ghost · 09-17-2018, 05:22 PM

Planning on doing this conversion to my '14 M Sport 328. Just bought 335i muffler and and M Sport dual diffuser. Excited!

JG_Coupe88 · 09-17-2018, 10:37 PM

Quote:

Originally Posted by N26Ghost

Planning on doing this conversion to my '14 M Sport 328. Just bought 335i muffler and and M Sport dual diffuser. Excited!

I have it on mine with 435i MPE, and MP diffuser, and I LOVE how it looks. So much more aggressive then before, enjoy yours and post a pic when it's done.

tboooe · 09-17-2018, 10:58 PM

Quote:

Originally Posted by JG_Coupe88

... and post a pic when it's done.

+1

N26Ghost · 09-18-2018, 02:16 AM

Will do!

fiveohwblow · 09-18-2018, 11:45 AM

Just did mine yesterday. Ordered the diffuser like a dolt and didn't realize (cause I didn't look) that my factory 328i bumper was molded in and not removable. Either way, i was just in an accident where I was rear ended so I told the shop to go ahead and cut it out to make it fit and had my body guy order the m sport bumper. Should be looking good as soon as I get the new bumper. For now, it looks and sounds great given the car is black you cant see the temporary hack job

09-24-2015, 08:53 PM	#1
tboooe Brigadier General 925 Rep 3,089 Posts Drives: F36 428i GC, E36 M3 - gone :( Join Date: Dec 2014 Location: The OC! iTrader: (1)	[SOLVED] 428 to 435 exhaust conversion now drone A while ago I successfully converted my 428 exhaust to a 435 one. Overall I am happy with it except I get an annoying drone between 1500 and 2000 rpm at around 40mph. Normally this doesn't bother me as I usually keep the rpms above 2000. However, when I am just driving casually around town the drone is bothersome. Does anyone else who did this conversion experience any drone? Is there any solution? If it matters I used the OEM muffler clamp instead of welding it. __________________ My build thread 2015 428i GC - Alpine White - Coral Red - M Sport Last edited by tboooe; 09-29-2015 at 03:02 PM..
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09-26-2015, 09:07 PM	#2
kirill_1361 Private 57 Rep 93 Posts Drives: F30 328i Join Date: Feb 2015 Location: La Jolla, CA iTrader: (6)	I did exactly the same conversion on my 328i. I read your thread and went to Mike's muffler shop to install the muffler. So everything is exactly the same, except I have N20 engine. I didn't have any drone for a first 500 miles. Then I disconnected the valve to make both pipes to be open all the time. That is where I started to notice the drone at around 40 mph. But I recently tuned the ECU on my car (didn't want to put any piggy box) and now I don't have any drone + the sound of the exhaust became meaner. I loved the sound with this muffler on the stock car but now it is totally different. Sounds more like a 335.
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09-28-2015, 01:00 PM	#3
mge92 SPEED RACER 375 Rep 740 Posts Drives: BMW X5 M50d BMW M2 CS Join Date: Jul 2012 Location: London iTrader: (2)	ROBNYC __________________ 2019 BMW X5 M50d Artic Grey \| 2020 BMW M2 CS Misano Blue Incoming - Ginetta G56 GT Academy \| Incoming - BMW X5M Comp Oxford Green RIP - 2020 Mini JCW GP Racing Grey \| RIP - 2013 X3 xDrive28i Carbon Black
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09-28-2015, 03:03 PM	#4
DG20 Lieutenant Colonel 967 Rep 1,771 Posts Drives: M340i Join Date: May 2014 Location: Los Angeles, CA iTrader: (5)	I did this conversion and i left my valve unplugged and i never get drone __________________ Instagram: @dg_g20
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09-28-2015, 03:52 PM	#5
MattTheCarNut Lieutenant 303 Rep 481 Posts Drives: 2023 G05 Join Date: Jan 2012 Location: Houston, TX iTrader: (1)	My valve is plugged in and no drone. What happens if I unplug it??? __________________ 2023 G05 Phytonic Blue/Cognac, M Sport, Prem Pkg, Parking Assistance Pkg, 22", M-sport red brakes, heated armrests, 4zone climate, HK, extended shadowline
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09-29-2015, 04:06 PM	#8
tboooe Brigadier General 925 Rep 3,089 Posts Drives: F36 428i GC, E36 M3 - gone :( Join Date: Dec 2014 Location: The OC! iTrader: (1)	Finally got this drone issue solved! Here is what I did: For this mod, I used the OEM muffler clamp to attach the muffler to the midpipe instead of welding. I did it this way so I could easily change back to the original 428 or other exhaust in the future. I got to thinking that perhaps the clamp or how it clamped the exhaust could have been what was causing the drone. When I looked at the exhaust more closely, specifically the exhaust tips, I noticed the muffler was rotated up so that the exhaust tips were horizontal, instead of slightly slanted downward as they are stock. The axis of rotation is around the two rubber vibration dampening pieces that the muffler attaches to. On the 335/435, you can see there is quite a bit of gap between the exhaust tip and the diffuser. In my case, there was hardly any gap. This caused the midpipe to be forced downward so that it sat dangerously close the frame cross brace. I am not sure the midpipe vibrated against the brace at certain RPMs causing the drone. I loosened the clamp, rotated the muffler so that the exhaust tips pointed down slightly which in turn raised the mid pipe away from the frame cross brace. After taking the car for a test drive I can report the drone is gone!!! I am not sure if I am imaging things but I would swear that the car revs quicker from 1500-2000 RPMs now. Anyway, if anyone has drone and used the muffler clamp it would be worth loosening it and readjusting the position of the midpipe. I hope this helps someone else. __________________ My build thread 2015 428i GC - Alpine White - Coral Red - M Sport
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09-29-2015, 10:19 PM	#9
F36 Pilot Private First Class 23 Rep 189 Posts Drives: 2015 428i GC Join Date: Jul 2011 Location: SoCal iTrader: (0)	That is great news! I know the drone would have bothered me too so I decided not to do the conversion after reading your original post about it. Now that you have fixed the problem and others who have done the conversion report no drone, I guess I'll be shopping for a 335/435 muffler.
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10-01-2015, 12:48 AM	#11
perrystacks Private First Class 25 Rep 108 Posts Drives: 428xi M Sport GC Join Date: Dec 2014 Location: Queens, NYC iTrader: (0)	i hear the same drone but i had my exhuast welded.. i am going to have to take a look at this again.
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09-17-2018, 05:22 PM	#15
N26Ghost Lieutenant 497 Rep 537 Posts Drives: 2014 BMW 328i M Sport Join Date: Mar 2018 Location: Elk Grove, CA iTrader: (0)	Planning on doing this conversion to my '14 M Sport 328. Just bought 335i muffler and and M Sport dual diffuser. Excited! __________________ '14 F30 328i M Sport // FBO // bm3 Stage 2+ DME Tune // Stage 1 TCU Tune // Apex EC-7s on Conti DWS06+s // 1 of 6 ever made of this spec (3C13 US-SULEV German-built //
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09-18-2018, 02:16 AM	#18
N26Ghost Lieutenant 497 Rep 537 Posts Drives: 2014 BMW 328i M Sport Join Date: Mar 2018 Location: Elk Grove, CA iTrader: (0)	Will do! __________________ '14 F30 328i M Sport // FBO // bm3 Stage 2+ DME Tune // Stage 1 TCU Tune // Apex EC-7s on Conti DWS06+s // 1 of 6 ever made of this spec (3C13 US-SULEV German-built //
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09-18-2018, 11:45 AM	#19
fiveohwblow Major 3633 Rep 1,397 Posts Drives: F15, E46 & M3, F82 Join Date: May 2016 Location: Desert SW iTrader: (1)	Just did mine yesterday. Ordered the diffuser like a dolt and didn't realize (cause I didn't look) that my factory 328i bumper was molded in and not removable. Either way, i was just in an accident where I was rear ended so I told the shop to go ahead and cut it out to make it fit and had my body guy order the m sport bumper. Should be looking good as soon as I get the new bumper. For now, it looks and sounds great given the car is black you cant see the temporary hack job Attached Images Last edited by fiveohwblow; 09-18-2018 at 11:52 AM..
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