Vibration tied to rpm

Alfalost · 04-14-2021, 05:00 PM

I have read numerous threads about a variety of vibrations, but I'm not at all clear any match the vibration I have.

I first became aware of it at a traffic light, and believed that it went away when the clutch was depressed. Therefore, I just spent a bunch of time replacing the clutch with a new Spec one. Also replaced rear subframe bushings, diff bushings, and transmission mounts while I was at it.

The clutch feels great.

The vibration is unchanged. The car idles smoothly. Around 2000 rpm, the vibration begins, and increases as rpm increases until it almost becomes a hum. It can be moving or at a standstill, in neutral or in gear. It isn't wheels or drivetrain, since it doesn't need to be moving.

Does this seem like an engine or an exhaust issue to you?

Johal E32 · 04-14-2021, 05:28 PM

Motor mounts?

Alfalost · 04-14-2021, 08:49 PM

The engine does not appear to move any differently at idle or when revved. Everything sits very flat and still.

amrazM · 04-15-2021, 05:23 AM

Quote:

Originally Posted by Alfalost

The engine does not appear to move any differently at idle or when revved. Everything sits very flat and still.

whats the mileage of your car? An exhaust vibration would be more noticeable at idle. If the mounts have not been changed that would be the first place I look.

CamasM3e93 · 04-15-2021, 09:19 AM

Motor mounts, agree with poster above. they are a known wear item and posters have reported torched mounts as low as 30k miles. I park on rubber mats to avoid flat spotting the tires overnight. Obviously not your issue with vibration at the stop light, but its another common cause of vibration tied to RPM or speed, resolving once the car/tires warm up.

Alfalost · 04-15-2021, 09:21 AM

Thanks!
I guess the front end is happening sooner than I had planned.

04-14-2021, 05:00 PM	#1
Alfalost New Member 5 Rep 7 Posts Drives: 2013 M3 Ci Join Date: Jan 2019 Location: SW Colorado iTrader: (0)	Vibration tied to rpm I have read numerous threads about a variety of vibrations, but I'm not at all clear any match the vibration I have. I first became aware of it at a traffic light, and believed that it went away when the clutch was depressed. Therefore, I just spent a bunch of time replacing the clutch with a new Spec one. Also replaced rear subframe bushings, diff bushings, and transmission mounts while I was at it. The clutch feels great. The vibration is unchanged. The car idles smoothly. Around 2000 rpm, the vibration begins, and increases as rpm increases until it almost becomes a hum. It can be moving or at a standstill, in neutral or in gear. It isn't wheels or drivetrain, since it doesn't need to be moving. Does this seem like an engine or an exhaust issue to you?
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04-14-2021, 05:28 PM	#2
Johal E32 Private First Class 163 Rep 183 Posts Drives: 91 M5, 98 M3, 08 M3 Join Date: May 2019 Location: Earth iTrader: (3) Garage List 1991 BMW M5 [0.00] 1998 BMW M3 [0.00] 2008 BMW M3 [0.00]	Motor mounts?
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04-14-2021, 08:49 PM	#3
Alfalost New Member 5 Rep 7 Posts Drives: 2013 M3 Ci Join Date: Jan 2019 Location: SW Colorado iTrader: (0)	The engine does not appear to move any differently at idle or when revved. Everything sits very flat and still.
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04-15-2021, 09:19 AM	#5
CamasM3e93 Friends don't let friends ESS 3152 Rep 871 Posts Drives: '11 Lemans Blue 6mt Harrop e90 Join Date: Dec 2020 Location: Camas, WA iTrader: (0) Garage List 2011 E90 M3 [9.00] 2003 Porsche 911 Turbo [9.75] 2019 BMW X5 xDrive40i [0.00] 2013 Mercedes E550 ... [0.00]	Motor mounts, agree with poster above. they are a known wear item and posters have reported torched mounts as low as 30k miles. I park on rubber mats to avoid flat spotting the tires overnight. Obviously not your issue with vibration at the stop light, but its another common cause of vibration tied to RPM or speed, resolving once the car/tires warm up.
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04-15-2021, 09:21 AM	#6
Alfalost New Member 5 Rep 7 Posts Drives: 2013 M3 Ci Join Date: Jan 2019 Location: SW Colorado iTrader: (0)	Thanks! I guess the front end is happening sooner than I had planned.
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