6mt conversion and X Clutch organic twin plate noises when driving - normal?

jzx_andy

Lurker
May 22, 2019
20
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Perth, Western Australia
Ride
2008 E92 335i 6MT
Hey guys,

Recently finished a 6mt swap on my car and just wondering if these noises are normal with this sort of clutch setup, as I've never driven a twin disk clutch car before and am quietly freaking out on whether I have broken something (or am potentially breaking something by driving the car), or if it is just part and parcel with this type of clutch and SMFW setup.


I've recorded the above video with the car as dead silent as possible (windows closed, radio off etc). The noises in this video occur when the clutch is engaged and the car is in gear. I am getting these sorts of noises on acceleration and deceleration when just plodding around town and it seems to vary with load, gear and rpm. Seems like it gets a little bit better with higher rpm but still pretty noticeable even around 4-4.5k rpm.

It isn't *that* loud, as having the window down and radio on will drown it out for the most part. But I am slightly worried about it and not sure if I could be experiencing an issue with my install or my clutch/transmission.

For background, the clutch pedal and gearstick engagement both seem normal, and the clutch is not slipping at all (albeit I'm driving around sedately during the break-in period). I've put about 280km on this setup and the noises haven't changed at all AFAIK. However, I understand that the noises I'm getting with the clutch pedal pressed in, and the car idling in neutral both sound normal for this clutch setup.

Current setup:
143,000 km on the clock
Used 135i transmission (~85,000 km claimed by seller)
Xtreme twin plate organic clutch (comes with a SMFW which I believe is made of steel and slightly heavier than the MFactory steel one)
Re-used the pilot bearing
Used the aftermarket metal throwout bearing that was included with the kit
Fresh oem clutch fork, locking clip and slave cyl
Fresh LT-03 fluid
Rogue engineering stainless steel pivot pin
OEM engine mounts, subframe bushings, diff bushings etc - all have NOT been changed
Rogue Engineering transmission mounts
Catless downpipes (they do not appear to be fouling the transmission)
Re-using the stock 3.46 small bolted diff, axles and driveshaft
Rest of the exhaust is stock

I plan on switching the transmission mounts back to stock tonight and will post an update.

Could I have done something really silly like not assemble the clutch correctly, not greased things up properly or not have topped up my transmission with fluid correctly? The trans came empty so I filled it up with about 1.9 litres of fluid before I could run it.

Any help would be greatly appreciated!
 
Last edited:

ShocknAwe

Captain
Jan 24, 2018
1,137
533
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Charleston, SC
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N54/3 1er ///Mutt
Reinforced OE engine mounts, RE trans mounts, solid 3.5" catless exhaust, organic Xclutch twin disc and mine doesn't rattle like that.

I DO get bad chatter when pulling out in first if I don't give it enough gas, or in reverse. But just moving in gear? No. Also at stop clutched out I have quiet rattle. Clutch in there's a shimmering metal sound which is the TOB.

I used new pilot and the metal TOB that came with the clutch, new fluid as well.

I think I'd try removing NVH parts like aftermarket mounts first and see where that gets you.
 
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jzx_andy

Lurker
May 22, 2019
20
28
0
Perth, Western Australia
Ride
2008 E92 335i 6MT
I've swapped back to OEM tranny mounts. Noise while driving has reduced by about ~30% but it's still prevalent up to about 3.5k rpm.

I am fine with the noise at idle and in neutral with the clutch out as that seems consistent with everyone else running a SMFW with an N5x.

Also forgot to mention that I have swapped my automatic harmonic damper for a used manual item. Worth a shot swapping to the auto damper and seeing if things improve?

Starting to think I should take it to someone who is experienced with twin plate clutch setups, just to make sure I haven't screwed anything up.
 

jzx_andy

Lurker
May 22, 2019
20
28
0
Perth, Western Australia
Ride
2008 E92 335i 6MT
You put to flex joints in your mids and noise will be gone, done this on a number of cars. If bmw out it there its for a reason

Thanks Marty. I gather there is nothing to be seriously concerned about in relation to the noises I've captured in the video and it might be an nvh or ancillary issue (like the exhaust, or old engine mounts, etc).

Getting some flex joints welded in should be an easy exercise. I will also throw on the manual diff, axles, driveshaft and fresh diff bushings on, just to be sure that it has nothing to do with the remaining automatic hardware that is sitting behind the gearbox.

It's a bit of a weird one for me, as the car seems to be driving fine, no weird noises, smells or clutch/shifter engagement, despite what I would expect with a brand new performance clutch with only 250km on it. I would have expected something serious to have happened if something went wrong with the clutch install, but in saying that, the noises don't seem normal at all to me haha!

I'll have someone more knowledgeable than me take the car for a spin so I can gather their thoughts in any event. There's only so much one can diagnose over the internet when it comes to these things. I'll post updates as I go along, just to add to the collective knowledge in here.