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Anyone solve the 3k Vibration?

86K views 355 replies 56 participants last post by  Cezary 
#1 ·
i've searched and read a bunch of posts about this but i dont see anyone ever getting this fixed or even properly diagnosed. right around 3k rpms i can feel a vibration through the seat/console/shifter area. its more noticeable reving in neutral but can be felt while driving to a lesser degree.
 
#104 ·
i wont be pulling the tranny till i eventually have to do the clutch. but i know im not putting another dm flywheel in. i dont want to jump to conclusions as idk if it is the problem. though the whole point of the dual mass flywheel as i understand it is to better dampen vibrations... not friggin cause them.
 
#109 ·
DM is 99% for driveline lash. Read Steve Dinan's white paper on harmonic dampers. The fact that it weighs 50lbs is more of the reason it damps out engine vibrations.

When I swiched to my UUC setup, there was a smidge more vibration than with the 50lb dual mass boat anchor. However losing 35lbs or
rotating mass did wake the engine up enough for it not to matter.
 
#108 ·
im not suggesting a ltw flywheel, just a standard weight single mass. idk, i think i'd rather have a slight rattle at idle than the vibration. though it dosent seem to cause any harm, as the one i checked had a bit over 100k on it. i just have to wonder if it is slowly causing any damage. it can't possibly be good for the drivetrain.

we still need to explore other options. im just guessing that the flywheel is the problem, it may not be. it could be the vib damper, or the exhaust, or something in the engine.
 
#114 · (Edited)
For koolmofo's drone, is there something that the engine drives that could rotate or pulsate with the frequency of the drone and put just enough of a strain on the engine that you could hear it in the engine note when you're lightly on or off the throttle? Power steering servo, oil pump, AC? Similar to when you switch the AC on or off, or turn the wheels while idling, the revs will ebb and flow slightly? Only now this would induce a bit more load (perhaps due to wear) and have a regular "pulse"?
 
#116 ·
Ok, didn't remember that :) Still, would you say these vibrations are the slower droning ones that koolmofo has, or the quicker ones that I have that feel like sitting on a miniature jackhammer? Can you count the drones at 3k or is it more of a quicker vibration? Say, 6Hz vs 25Hz?

What I was suggesting was really only applicable specifically to koolmofo's droning sound and not to the vibrations that I can hear and feel in my car.
 
#117 ·
i think everyone's is slightly different. some can feel it more and hear it less, others have the opposite. mine i think is more similar to his video but the sound is not as loud. i've noticed also that in the rpm range where it starts to shake that the exhaust tone changes also. it almost sounds like the engine is missing slightly, but i dont think it is.

think of a wheel/tire that is out of balance. do you feel the shake all the time? no, usually only at certain speeds. as you hit the speed range you feel the shake, then as you increase speed it is less apparent. sounds like the same thing we are talking about here huh?
 
#118 · (Edited)
I did some vibration measurments last night over the gearbox and at idle. The idle speed is 960rpm/16hz. Its a very high idle, think I have some problem with the oil seperator lines.

Anyway, I got 3,2 mm/s RMS on the flange between the engine and transmission, vertical direction and 3,1 mm/s RMS horizontal direction. On the rear end if the transmission I got 2,7 mm/s rms on both vertical and horizontal (there is no rotating on out going parts here anyway since the shifter is in neutral)

The components that are the cause of the vibration on the front of the transmission is not a 1xRPM but a 2,66xRPM component. This means that I can rule out unbalance in the flywheel for now since a unbalance will only occure once every rotation, or 1xRPM. We can see a sligthly component at 1xRPM but this is normal on rotation parts. The value are not high.

I will try and take some vibration measurments while driving the car.
 

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#122 ·
You being with no exception a professional in this field, would you consider looking from these results that we're talking about a mass that's spinning? How about if a vibration damper that's bounching back and forth while spinning (from a small play), could it cause this?

Would there be any help, if you measure the body itself? Because clearly the vibration is felt there.
 
#119 ·
Arotished, I will try and make some more recordings of my engine drone at idle, vs where it is most noticeable (just above 2000rpm), and post on youtube. Perhaps you can use you measuring equipment to derive the frequencies, and compare these to a normal sounding m5 engine at the same rpm's.
 
#120 ·
Well, I have to say I am ecstatic! Today I just brought the beast home from the dealer...with no vibration! I have Tubi's on and I was told by the original owner that the vibration was related to the exhaust. The dealer took off the aftermarket urethane trans mounts and replaced them with stock BMW factory mounts...problem gone! I have to say I can't believe how smooth it is. I have always heard the difference in the tone of the exhaust as well...or at least I thought I could. After almost two years of ownership I have a new heightened appreciation for my beast. Hope this helps some of you.
 
#124 ·
i dont think its the crankshaft. if it was out of balance that much it would probably destroy the engine in a short period of time. yesterday i had one of our gm techs who is really good with vibrations check it. he thinks that it is not the flywheel because when the clutch is slightly depressed it dosent change the vibration at all. he said this should put enough pressure on the flywheel to change it if it were the problem.

arotished, try taking some measurements on the exhaust and the front of the engine also. maybe even the places inside the car where it is felt.
 
#125 · (Edited)
Yes, and if it was a unbalance you would have REALLY felt it on high rpm. And like you say, if you release the pressure from the pressureplate and dont feel any diffrent then it not related to the flywheel. One one thing, the flywheel is made by 2 pieces that you can move/rotate seperatly (about one inch or something)

I know my headers are vibrating more but i didn't record the values from each header. I will tray and pull the vibration leads from the probs to the colelctor throu where the shifter goes throu the body so that I can record while driving.
 
#126 ·
Valkman,
My vibrations were most noticeable around 2700 RPM through 3000. I would really feel it through the body of the car during gradual acceleration, holding it there, or backing off a higher rpm. When it was at this point, the exhaust seemed to resonate at a higher lever and the sound was different. I could shift out of it, and could get the vibration while not moving at that rpm. Based on all the posts, I would tend to think most of us are talking about the same thing. (From a wear standpoint, I just turned 40,000 miles this week).
 
#128 ·
having read the things about 3k vibration and suffered from a similar problem i took my car to the service

m7 car is at 60k miles with original clutch

i told them to check guebo and it's "friends" first

then bingo...they are all gone

but my vibration is something strange, yes around 3k but also when i put the gear into neutral i feel a bouncing in low speeds...strange

i had exactly the same vib in Z4, and the problem was spotted to be from guebo....

today they are replacing them....will let u know about the result
 
#129 · (Edited)
Vibration damper... that's what I'm thinking right now... but who knows... (devil knows)

So I called my friend, who's an expert in NVH- field, so we could have a get-together according the vibration. According to him this sounds more like a natural frequency thing than a spinning item being out of balance... Will be doing some measurements with him later on.
 
#132 · (Edited)
im really curious also about how the associated sound is being generated. i got in the car before and really slowly brought the rpms up, and really paid attention to where it starts. right at 1500 you can actually start to feel the vibration, but it is not as severe at that speed. also at that rpm the noise accociated is the most prominent. at 1500 i can feel the vibration, but it is not steady. it has a "beat" to it, it comes like once every half second. then as i bring the revs up a bit higher it pretty much dissapears till a hair over 2500 where it starts again and becomes worst at 3000. notice anything here? 1500 + 1500 = 3000. i cant tell cause after a bit over 3k its too hard to feel but i bet its there at either 4500 or 6000rpms as well. try this guys, everyone who has this please try and report back. put the car in neutral and very slowly bring up the rpms, really pay attention to where you feel/hear it and at what rpm

today at work our FSE(field service engineer) aka bmw rep, was there. i spoke to him about the vibration and asked him if he has ever encountered this problem. he said that he has heard of it. didnt have time to have him actually feel it today but next visit he is going to check it out. he thought that it could be either the crankshaft out of balance or the flywheel. the good thing is that it looks like he is going to help me and we also spoke of a possible goodwill repair.
 
#147 ·
im really curious also about how the associated sound is being generated. i got in the car before and really slowly brought the rpms up, and really paid attention to where it starts. right at 1500 you can actually start to feel the vibration, but it is not as severe at that speed. also at that rpm the noise accociated is the most prominent. at 1500 i can feel the vibration, but it is not steady. it has a "beat" to it, it comes like once every half second. then as i bring the revs up a bit higher it pretty much dissapears till a hair over 2500 where it starts again and becomes worst at 3000. notice anything here? 1500 + 1500 = 3000. i cant tell cause after a bit over 3k its too hard to feel but i bet its there at either 4500 or 6000rpms as well. try this guys, everyone who has this please try and report back. put the car in neutral and very slowly bring up the rpms, really pay attention to where you feel/hear it and at what rpm

Yes, I realized before, that the first vibe is somewhere at 1500 rpm and the second after 3000 rpm... but the biggest news is, that I tried today at work and got those same 3200 rpm vibrations on a 2006 Range Rover with 4.4 liter V8! That luxury car has almost no vibrations from the road surface through wheels, not to mention from the drivetrain/engine. But bringing the revs up at standstill brings the vibration to the body exactly at 3200 rpm... Are we talking about characteristics on big V8 engines, that for some reason are transfered to the body in our cars more stronger?

When I started reading this thread I had a suspicion, that it is so called secondary resonance vibration (excuse me if i didn't name it correctly, it was long time ago i've read about it)
Basically any engine has those vibrations, but for example in 4 cylinder which is already so unbalanced you don't feel it as much cause it's shaking all the time anyway.
For example on my mondeo, i've got 2.5 litter V6, and I can easily get the same sort of vibrations at about just over 2000 revs, it's just at a different rate (i.e. faster), the engine starts sounding as if it run out of oil. Mind you, one feels it only if at a stand still brings the revs slowly up, and then at above 2000 rpm you feel the very same vibration.
This situation leeds to engineers adding the counter-balancing shafts which do reduce lots of vibrations from the engine, for example in mondeo's V6 there are 4 and it is the smoothest engine i've ever heard. apart from this little spot just over 2000 revs

Also one of the most naturally balanced engines is a straight six, and that was the reason why BMW and Mercedes were using it in all their cars (and 4 cylinder budget engines of course) before the end of 80s when they started all this v8 and v12 madness. strictly saying v12 is more naturally balanced engine as it's two straight sixes together, v8 though is not an ideally balanced engine at all as it is two straight 4-cylinders together.

The reason that it appears on certain revs is that many different rotating parts (rotating at a different speed) at a certain point get into resonance with each other, hence why that vibration and sound do not match any rotating component's speed in the engine. And that's why Valkman could easily find this vibration on the range rover's v8 - cause they all (not range rovers, engines i meant :D ) have it. That's why you get it on 1500 RPM and then at 3000 RPM - certain rotating parts get into resonance with each other. Of course you probably will not feel it at 4500 and 6000 as the vibration is faster than what you would register. The very same thing for example with a disbalanced wheel - itis the worst at around 70 mph, and after let's say 100 mph you don't feel it anymore (does not mean it does not vibrate though)
It's just that with ageing or worn out engine/tranny mounts this sound and feeling can be amplified, compared to a new car, where everything is new and isolates this vibration from the driver much better. So the conclusion is to change all the engine/tranny mounts and it is going to reduce significantly the vibration, and nothing much you can do i guess...

Engines vibrate:M5launch: sorry if my mumbling is no help

Regards,
Tony
 
#135 ·
Yes, I realized before, that the first vibe is somewhere at 1500 rpm and the second after 3000 rpm... but the biggest news is, that I tried today at work and got those same 3200 rpm vibrations on a 2006 Range Rover with 4.4 liter V8! That luxury car has almost no vibrations from the road surface through wheels, not to mention from the drivetrain/engine. But bringing the revs up at standstill brings the vibration to the body exactly at 3200 rpm... Are we talking about characteristics on big V8 engines, that for some reason are transfered to the body in our cars more stronger?
 
#136 · (Edited)
Wow was I glad to see this thread.

I have the exact same vibration as described earlier in this thread by nightkrawler. Some other interesting points for me:


  1. 2002 M5. Engine is stock, but I do have a Britalman exhaust on the car.
  2. Vibration was really bad - I replaced the exhaust mounts near the transmission with new "black" mounts. My only problem here is that the mounting tabs don't line up exactly with the tabs on the car...so the mounts are really sheared. The vibration is reduced since I did this, but still very noticeable.
  3. Vibration occurs with or without engine in gear, with or without the clutch in or out. Primarily on gradual deceleration.
  4. One thing I didn't notice anyone else mention: For me, it's worse through deceleration in gears 1, 3, and 5. Not as bad in 2, 4, 6. Don't ask me why. It's by far the most noticeable for me in 3rd gear at 3,000 rpm (around 60mph?) slowly coming down in revs. Not sure if this is useful information, or purely coincedental in my case.
  5. Car has 43,000 miles - very similar to the miles of the other cars mentioned.
  6. Original clutch in the car, I believe. I have no documentation that it's been changed.
  7. I'm getting clutch slippage (when car is cold, mostly, but can occur any any time) in 2nd gear under hard acceleration. I'm assuming at a high intensity 43k miles, that this clutch is done.
My next steps were going to be the following:

  1. Replacing the trans mounts with UUC black rubber trans mounts
  2. Replacing the stock clutch with the v12 option from UUC - including the lightweight flywheel, etc. (UUC E39 M5, 540i, and Z8 Ultimate Lightweight Flywheel and Clutch conversion)

Is there anyone running a UUC Motorwerks V12 conversion kit who has this vibration? Do all of the cars showing vibration have an aftermarket exhaust?


One last piece: nightkrawler, thanks very much for this thread and the hard work going into it. My simple thought process led me to feeling that this was related to either the engine mounts, trans mounts, or flywheel. Your work in this regard has been great. I read all 14 pages hoping at the end you would have a post that said "Okay, fixed: here's what I did." But I'm sure we'll get there.
 
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