[dzenno]

Do you have ANY vibration you can feel while decelerating (foot off throttle, no brakes)...I get some vibration from about 3000rpm to 2500rpm and only in this range ... Thinking this might be the single mass lightweight flywheel I put in very recently...for me happens in 2nd, 3rd, 4th (less pronounced) and 6th (loudest)... There's no vibration if I rev the car in neutral, 1st or 5th...

Does this even make sense that it's the flywheel and torsional vibrations...as soon as you touch throttle it goes away...

Other than this the clutch/fly work amazing...

[dzenno]

Bump...

[GaryS]

Edit: Oops, I do not have a lightweight flywheel.

[lamia2super]

i haven't noticed any vibration

[dzenno]

was just about to ask which one you had...

to me it seems like its not flywheel related as it would happen on accel as well as when stopped and just revving the car up/down...

The only other reason this would happen that might make sense is damaged motor mounts (specifically driver's side one) as it happens on decel but that would be weird, no?

[e93WhiteonRed]

You should get that checked out ASAP. Any vibrations in an engine aren't good, but when they are connected to the crank shaft, it will tear up your main bearings and thrust bearings. I blew up a 306 i had in an old mustang becuse of a slight imbalance and vibration that I didn't pay attention to. It caused a crack in the webbing that one of the main caps bolted to and caused a HUGE failure. Get it checked out. A machine shop should be able to check the balance of your flywheel.

[dzenno]

Originally Posted by lamia2super

i haven't noticed any vibration

which one are you running?

[dzenno]

Originally Posted by e93WhiteonRed

You should get that checked out ASAP. Any vibrations in an engine aren't good, but when they are connected to the crank shaft, it will tear up your main bearings and thrust bearings. I blew up a 306 i had in an old mustang becuse of a slight imbalance and vibration that I didn't pay attention to. It caused a crack in the webbing that one of the main caps bolted to and caused a HUGE failure. Get it checked out. A machine shop should be able to check the balance of your flywheel.

question is how it could be the flywheel if it doesn't vibrate in 1st or 5th at all, as well as acceleration in any gear...its only on decel and only in 2nd, 3rd, 4th and 6th and only as the engine decelerates on its own from about 3000 to about 2500 rpm...everywhere else its super smooth..

[lamia2super]

i have the spec stage 3 i believe same as ASR

[e93WhiteonRed]

Well - was anything else changed? If everything else is stock but the flywheel then either the shop put something back together too loose or the flywheel is faulty. There could be some excessive play in your input shaft that causes the clutch discs to engage off balance and you only notice it because the gears in the transmission are helical so it has no play on accleration and excess play on decelaration because it pushes the input shaft out.

There is a ton of reasons it could happen, but bottom line is you changed something, now there is a vibration, and vibrations are BAD and need to address it...

[e93WhiteonRed]

FYI just saw your sig and see you have an aftermarket clutch.... more variables now to diagnose.

[Former_Boosted_IS]

Dzenno, I know you have fought through this concern for a while, so I decided to call one of the main techs at Clutch Masters that I dealt with during my project. I mentioned some of the vibrations that you experienced and some of the small vibrations I have experienced.

For complete transparency, I have experienced slight vibration acceleration lightly during the 2500-3000 rpm range on lower gears. I asked a few people about it and all said vibrations / more gear noise are common with LWFW on E36/46/9x.

With that said, I know you have been really concerned Dzenno, so I called to talk to them. Clutch Masters said all flywheels are neutrally balanced and tested before they leave the shop... which I think we all expect anyway. With that said, it is very easy to see if you flywheel is out of balance. Simply out the car in nuetral and rev through that RPM. If there is no vibration then it is not the flywheel. I went out to my car to test this and it is smooth as butter through all rpms. That means as expected, this must be originating within the transmission and after the flywheel. Everyone I spoke with said this was likely the cause, but I still wanted to check with Clutch Masters so we have a definitive answer. They have been incredible to our community and their customer service is still at the top of the chain.

I guess the question then becomes how do you get rid of the gear noise within the transmission that is now being transmitted through the LWFW. The answer is to change the tranny fluid incrementally to a higher weight fluid. The negative to this is that it can cause it to be tough to get into some gears while it the fluid is cold. I think the wise thing is to slowly and incrementally change the weight of the fluid until you are happy. This is an excercise that would likely benefit the community regardless, so I may begin this process. I know BMW's trannies have syncros that can be sensitive to certain transmission fluids, so I will take that into account.

Regardless, I hope this does help put your mind at ease. I sincerely think this is gear noise and nothing to worry about.

[dzenno]

FBIS, really appreciate your help here...not many ppl are running single mass lightweight flywheels on their E90s yet so its hard to get any opinions from actual users that are running them...another member on this board is running the Fx400 with this same flywheel on his 335 and he told me yesterday that his is vibrating too the same way, so that's strange?? no vibrations reported from users of the spec flywheel...

what's funny is that I talked to clutch masters today as well I explained everything to them and they actually said exactly what you're saying, that due such dramatic change in weight of the flywheel there's a vibration...they didn't say it wasn't the flywheel, just said it must be the dramatic change in weight and to call them back if it got worse...i was surprised actually as i expected that chatter at idle and take off would be the only issues after install, not this...

changing to a thicker fluid might help a bit with gear chatter that you can feel in the shifter (really not much of this happening anyway on my car) but the vibes i get aren't that miniscule especially in 6th gear...if you're in 6th cruising on the highway the engine doesn't decelerate that quickly on its own from 140-120km/h...takes a while, unless you use brakes...what's funny is that tonight I didn't notice vibration in 4th any more, sort of comes and goes certain days...its always there in 3rd and 6th for sure, 6th is strongest...

what's also weird is that sometimes, and this might just be me after listening to this thing constantly, while the car is still cold if I don't accelerate quickly at all, and just slowly accelerate from neutral to 1st to 2nd to 3rd and then let it decelerate in 3rd through this 3000-2500rpm range the vibes will still be there but a LOT less...if i then hit the gas pedal and accelerate a bit hard then let it decelerate on its own, its perfectly smooth again down to 3k and then "seems" to vibrate a bit harder (note their's ZERO noise) down to 2500...

i tried revving in neutral like you mentioned and i'm not 100% but i think there's a very very very tiny vibe as the rpms drop through 3000-2500, really not sure...if I wasn't feeling for it i wouldn't notice it for sure...

this confuses the sh*t out of me the only way to figure out if it really is the flywheel is to take it out and swap my oem one back in and see...issue is cost obviously as I can't do this on ramps but lets say if I do that and given the clutch has already been worn in on the CM fly does the OEM flywheel need to be prepared in any way before I swap it back in?

[Former_Boosted_IS]

Honestly, I am not sure what else to say at this point? You said if it is normal that you can accept it, but from your post it sounds like this is not really acceptable to you. I was very clear when you asked me about a LWFW that it would increase both noise and vibration on your car.

If you look at the DMFW, you will see a 38 lb monster. Rotate each flywheel plate and you will notice about a 30 degree play between the two flywheels. The DMFW was created for one reason and it is not performance. It was created to reduce noise from a loud BMW engine and noisy tranny. There is no secret here. If you get a chance to speak to any of our BMW experts from Europe, you can get some good info on the origin on this DMFW on the E36/46/9x. From what I understand, the DMFW was a cheaper solution to customers complaining about loud BMW engines and noises from the trannies. The long and short is the DMFW is a effective device used to cancel noise and it is horrible for performance, rev matching, and shift smoothness.

It should also be noted that some of the Euro spec LWFWs also have the same vibration.

If you change back to the DMFW, then I am 100% sure your noise will be gone. Before you jump and do this, why not try different fluids first? This is specifically why I have said a lightweight flywheel is not for everyone.

One last point to note, I am not sure if you went with a sprung or unsprung hub, but sprung hubs do tend to dampen some of the vibrations introduced with a lwfw.

[dzenno]

Originally Posted by Former_Boosted_IS

Honestly, I am not sure what else to say at this point? You said if it is normal that you can accept it, but from your post it sounds like this is not really acceptable to you. I was very clear when you asked me about a LWFW that it would increase both noise and vibration on your car.

If you look at the DMFW, you will see a 38 lb monster. Rotate each flywheel plate and you will notice about a 30 degree play between the two flywheels. The DMFW was created for one reason and it is not performance. It was created to reduce noise from a loud BMW engine and noisy tranny. There is no secret here. If you get a chance to speak to any of our BMW experts from Europe, you can get some good info on the origin on this DMFW on the E36/46/9x. From what I understand, the DMFW was a cheaper solution to customers complaining about loud BMW engines and noises from the trannies. The long and short is the DMFW is a effective device used to cancel noise and it is horrible for performance, rev matching, and shift smoothness.

It should also be noted that some of the Euro spec LWFWs also have the same vibration.

If you change back to the DMFW, then I am 100% sure your noise will be gone. Before you jump and do this, why not try different fluids first? This is specifically why I have said a lightweight flywheel is not for everyone.

One last point to note, I am not sure if you went with a sprung or unsprung hub, but sprung hubs do tend to dampen some of the vibrations introduced with a lwfw.

I would definitely accept a minor vibration but what happens on my car in 6th gear isn't minor...Again, its not noise, its vibration that makes the entire inside of the car vibrate, pretty much the same like when you have bad alignment in the rear...

I think you missed my comment on the SPEC flywheel...that one is 2lbs lighter (14lbs) and of the ppl I asked (jpsimon, shiv and lamia2super that I've talked to so far) they have no vibration like I describe...I didn't go with SPEC because of bad rep they got all over the place including turkish335 whom i know personally and know/heard what kind of BS he's gone through with SPEC due to his clutch, that's a whole story for itself...

It sounds like yours and my issues are a bit different though...you indicate only a very minor vibration and only in lower gears (which gears and is it negligible enough that you don't have to change gear if you happened to be crusing at that RPM)..In my case its a considerable vibration especially in 6th where you really want to shift down to 5th, can't ignore it...I'm really just trying to get to the bottom of what the source is as it might be something else that's making the vibration on my car way more pronounced than on yours (e.g. bad motor mount, just as an example)...

I don't understand the 30 degrees play between the two when you rotate them comment...can you explain? In terms of the sprung/unsprung hub, I got the fx400 6 puck ceramic clutch kit with the flywheel when I ordered, didn't know sprung vs unsprung was an option...pretty sure its sprung...still have their boxes and could ask STETT what they sent me? Can that fx400 6 puck be either sprung or unsprung?

[Former_Boosted_IS]

Originally Posted by dzenno

I would definitely accept a minor vibration but what happens on my car in 6th gear isn't minor...Again, its not noise, its vibration that makes the entire inside of the car vibrate, pretty much the same like when you have bad alignment in the rear...

I think you missed my comment on the SPEC flywheel...that one is 2lbs lighter (14lbs) and of the ppl I asked (jpsimon, shiv and lamia2super that I've talked to so far) they have no vibration like I describe...I didn't go with SPEC because of bad rep they got all over the place including turkish335 whom i know personally and know/heard what kind of BS he's gone through with SPEC due to his clutch, that's a whole story for itself...

It sounds like yours and my issues are a bit different though...you indicate only a very minor vibration and only in lower gears (which gears and is it negligible enough that you don't have to change gear if you happened to be crusing at that RPM)..In my case its a considerable vibration especially in 6th where you really want to shift down to 5th, can't ignore it...I'm really just trying to get to the bottom of what the source is as it might be something else that's making the vibration on my car way more pronounced than on yours (e.g. bad motor mount, just as an example)...

I don't understand the 30 degrees play between the two when you rotate them comment...can you explain? In terms of the sprung/unsprung hub, I got the fx400 6 puck ceramic clutch kit with the flywheel when I ordered, didn't know sprung vs unsprung was an option...pretty sure its sprung...still have their boxes and could ask STETT what they sent me? Can that fx400 6 puck be either sprung or unsprung?

These vibrations have been on BMW clutches for years. UUC has a good writeup on them. I strongly suspect SPEC is using a sprung hub on the clutch to reduce vibration, but someone will have to chime in. On the downside the SPEC LWFW makes the car sounds like a diesel truck where my chatter is negligable at best. I don't k know whether the FX400 is a sprung hub or not. Did the clutch have a solid disk or springs on it?

I am not sure what else to say. I can tell you that yes I would prefer no vibration, but I knew full well that extra noise and vibration are quite common with LWFWs. A quick search reveals tons of responses on driveline rumble as this is referenced. I accepted that possibility before choosing a LWFW design. It sounds like this is not something you are willing to accept and that is 100% your choice. If you feel you have a defective product or the flywheel is a defective design, then you should speak with manufacturer. If not, I am not sure what you can do other than can go back to the DMFW.

Understand the DMFW was only designed to eliminate all noise. The 30 degree play is not there for performance but to provide dampening (that is all I meant). As I have stated from day 1, if quiet is your #1 determining factor then a lwfw is simply not for you.

[dzenno]

You're completely right on chatter. On my car is barely noticeable as well, only when AC is on (rpm around 800), but other than that its totally acceptable chatter wise...

I honestly thought fx400 kit I bought came with the sprung hub but I'll double check this...

I totally understand the point of the DMFW on these cars...i was just surprised to see that one flywheel would vibrate as mine did while the other wouldn't....

again, i'll have to look into sprung/unsprung, now not sure what I got...

[Former_Boosted_IS]

Originally Posted by dzenno

You're completely right on chatter. On my car is barely noticeable as well, only when AC is on (rpm around 800), but other than that its totally acceptable chatter wise...

I honestly thought fx400 kit I bought came with the sprung hub but I'll double check this...

I totally understand the point of the DMFW on these cars...i was just surprised to see that one flywheel would vibrate as mine did while the other wouldn't....

again, i'll have to look into sprung/unsprung, now not sure what I got...

Let's start by looking at the hub then going from there. Second, I may try some heavier tranny fluid to see how this affects things too.

[dzenno]

Its sprung, just got this from STETT's GB thread on this board:

"The FX400 System uses the Power Plus I Pressure Plate with a custom, extremely durable, Sprung Ceramic disc."

BUT, it also says this:

"(WARNING) Due to the solid (no Marcel) friction rivet design, the FX400 disc engages very quickly and may chatter slightly in first and reverse. To help alleviate this problem, we only use premium ceramic friction material."

Wondering what fluids would be ok to try...currently its OEM which by the looks of it should be MTF-LT-3 which is a pretty thick fluid...

EDIT: UUC recommends a specific mix of transmission fluids, 1 bottle Redline 75W-140NS and 1 bottle Redline D4 ATF...what do you think?

[Former_Boosted_IS]

Originally Posted by dzenno

Its sprung, just got this from STETT's GB thread on this board:

"The FX400 System uses the Power Plus I Pressure Plate with a custom, extremely durable, Sprung Ceramic disc."

BUT, it also says this:

"(WARNING) Due to the solid (no Marcel) friction rivet design, the FX400 disc engages very quickly and may chatter slightly in first and reverse. To help alleviate this problem, we only use premium ceramic friction material."

Wondering what fluids would be ok to try...currently its OEM which by the looks of it should be MTF-LT-3 which is a pretty thick fluid...

EDIT: UUC recommends a specific mix of transmission fluids, 1 bottle Redline 75W-140NS and 1 bottle Redline D4 ATF...what do you think?

I thought about trying the UUC cocktail, but haven't decided. I spoke with Bird's Auto and they recommend trying GX80. Why not give the UUC a try first. Report back, then if it is not helping then I will get the GX80 to try.

[dzenno]

Would I damage anything (e.g. synchros) with this cocktail fluid? I guess if it smooths out the vibrations and allows me to shift fine there's more good than bad with it? What do you think?

Question I had about vibrations on your end that you mention you get in lower gears...which gears do you feel this in and is it more from the front/middle/rear of the car?

[Former_Boosted_IS]

Originally Posted by dzenno

Would I damage anything (e.g. synchros) with this cocktail fluid? I guess if it smooths out the vibrations and allows me to shift fine there's more good than bad with it? What do you think?

Question I had about vibrations on your end that you mention you get in lower gears...which gears do you feel this in and is it more from the front/middle/rear of the car?

The problem with comparing to me is I have to massive 8.5" clutch discs. One is a ceramic sprung hub and the other is a kevlar full face unsprung hub. It means the way my clutch absorbs vibrations will differ from yours. To be honest, I can tell it is simply some "Q" harmonic frequency that is transmitted. I suspect thicker fluid could only help.

As for the cocktail, UUC insists this is safe for our synchros, so I don't see a problem. I asked them about it once and then got busy with other reviews.