MFactory CF Drive Shaft

[peter de la mare]

Hopefully that’s a one-off as I am planning on ordering one and I couldn’t go through the same vibration experience again. How severe is the vibration, does it make the car undriveable?

[JetBlack_M3]

Originally Posted by peter de la mare

Hopefully that's a one-off as I am planning on ordering one and I couldn't go through the same vibration experience again. How severe is the vibration, does it make the car undriveable?

Others haven't experienced this issues. My vibration and humming is scary after 140mph

[Acetech]

Sounds like your driveshaft is imbalanced, you sure your friend is being honest about it being fine for him?
If your guibo is new and installed correctly and you don't have any oddities in angle between transmission and differential ( have you changed the mounting height) and the transmission mounts are in good condition it's got to be the shaft.

[pbonsalb]

Maybe the friend never went 120 mph. Probably half the M3s produced have never been over 100.

[wyatth]

Are you sure its a V2 with the kevlar/yellow stripes? You mentioned they were faded but the photo really doesn't show them.

[VAC_M3]

I want to buy this driveshaft for my e92 m3 6MT. Please email price and lead time to nickmvac@gmail.com

[Epoustouflant]

Originally Posted by nickmvac

I want to buy this driveshaft for my e92 m3 6MT. Please email price and lead time to nickmvac@gmail.com

Working on a group buy for this right now, stay tuned.

[6ixSpd]

Originally Posted by JetBlack_M3

Others haven't experienced this issues. My vibration and humming is scary after 140mph

Was this resolved for you?

[Vybz]

Originally Posted by JetBlack_M3

Others haven't experienced this issues. My vibration and humming is scary after 140mph

You aren't the only one. I also have massive vibration on long straights when the car reaches excess of 130+ MPH. I have solid aluminum subframe bushings and aluminum/delrin differential bushings. It's definitely the propshaft, as it never happened before with the OEM 2 piece shaft, and that was the only change made to the car prior to the start of the track season.

I agree with pbonsalb in that I doubt most people take their cars up to those speeds, so they probably never even notice. From 0- 125ish there is absolutely no NVH, anything past that and the vibration can be felt through the floor. A passenger described it as "being in a massage chair" (yes it's that noticeable).

Not sure if Team M Factory wants to chime in on this?

[Vybz]

Originally Posted by wyatth

Are you sure its a V2 with the kevlar/yellow stripes? You mentioned they were faded but the photo really doesn't show them.

My version is definitely V2, and has excessive vibration at 125+ mph. Jet Black is not alone in this.

[MFactory]

Originally Posted by Vybz

You aren't the only one. I also have massive vibration on long straights when the car reaches excess of 130+ MPH. I have solid aluminum subframe bushings and aluminum/delrin differential bushings. It's definitely the propshaft, as it never happened before with the OEM 2 piece shaft, and that was the only change made to the car prior to the start of the track season.

I agree with pbonsalb in that I doubt most people take their cars up to those speeds, so they probably never even notice. From 0- 125ish there is absolutely no NVH, anything past that and the vibration can be felt through the floor. A passenger described it as "being in a massage chair" (yes it's that noticeable).

Not sure if Team M Factory wants to chime in on this?

There isn't really anything for me to "chime in" on that hasn't already been stated by others before unfortuntately

However, if you would like to return the driveshaft to us for testing/diagnosis, we are more than happy to help

[wyatth]

^ I was really hoping for more, tbh! Is this normal? Potential issue/causes?


Can others with this please confirm they’ve tested up to 140+? While I won’t hit those speeds often, I don’t want to practically limit my cars top speed by a shaft that’s only balanced to that point.

[MFactory]

Originally Posted by wyatth

^ I was really hoping for more, tbh! Is this normal? Potential issue/causes?


Can others with this please confirm they’ve tested up to 140+? While I won’t hit those speeds often, I don’t want to practically limit my cars top speed by a shaft that’s only balanced to that point.

It's not normal, no, and we have had customers testing at those speeds with no issues.

Hence the only way to check to see if it is the driveshaft itself is to get it tested.

[peter de la mare]

Maybe there are other variables such as solid diff/subframe mounts that would normally absorb any vibration if they were OE?

I know I keep harping on about it, but I had a nightmare with the J-Fiber shaft as it shook the car violently over 130mph. It went back to J-Fiber for checking and more balancing but it made zero difference. The shipping costs and customs issues of this weren’t cheap.

If they are indeed balanced up to 12,000rpm As advertised then I feel a lot better about them, as I discovered later that the J-Fiber ones were only good to 6,400rpm, which with a 3.62 final drive correlates exactly to 130mph.

[rhyary]

I can confirm no vibration at 132-135mph and 3.62 diff.

Solid rear subframe bushing and purple diff bushings (not solid but close)

Mfactory gen-1

[SYT_Shadow]

I hope this isn't a problem. At two tracks I see 155mph...

[Bartledoo]

Originally Posted by Vybz

My version is definitely V2, and has excessive vibration at 125+ mph. Jet Black is not alone in this.

Can confirm as I've ridden in this high speed massage chair on track.

[MFactory]

Changes in mounts (particularly solid mounts) as well as suspension (solid/stiffer chassis bushings, spherical mounts, camber, caster etc) can cause an increase in NVH at high speeds, especially as your new driveshaft weighs less than 6kg and absorbs zero of the NVH that is transmitted through your driveline. Similarly, incorrectly torqued driveshaft bolts, misaligned pumpkin, drivetrain "noise" etc can also be a cause.

You can't really compare it to the oem driveshaft as that is 2pc, made of steel and weighs significantly heavier, so it absorbs a lot of driveline NVH.

This is not an excuse or refusal to accept responsibility for any issues. As mentioned, we are more than happy to test the driveshaft on our balancing machine and, if it is out of spec, we will reimburse any shipping costs involved.

[peter de la mare]

Originally Posted by SYT_Shadow

I hope this isn't a problem. At two tracks I see 155mph...

Same, especially at the Nurburgring, the car is close to topping out in 7th. A couple of other tracks are 140mph+

[peter de la mare]

Originally Posted by MFactory

Changes in mounts (particularly solid mounts) as well as suspension (solid/stiffer chassis bushings, spherical mounts, camber, caster etc) can cause an increase in NVH at high speeds, especially as your new driveshaft weighs less than 6kg and absorbs zero of the NVH that is transmitted through your driveline. Similarly, incorrectly torqued driveshaft bolts, misaligned pumpkin, drivetrain "noise" etc can also be a cause.

You can't really compare it to the oem driveshaft as that is 2pc, made of steel and weighs significantly heavier, so it absorbs a lot of driveline NVH.

This is not an excuse or refusal to accept responsibility for any issues. As mentioned, we are more than happy to test the driveshaft on our balancing machine and, if it is out of spec, we will reimburse any shipping costs involved.

My issue wasn’t NVH or noise. The whole car was shaking itself violently, certainly couldn’t maintain the speed with any level of mechanical sympathy. I think I have a video somewhere, I’ll try and find it. This isn’t an MFactory shaft to be clear.

[Vybz]

Originally Posted by MFactory

There isn't really anything for me to "chime in" on that hasn't already been stated by others before unfortuntately

However, if you would like to return the driveshaft to us for testing/diagnosis, we are more than happy to help

I appreciate that, and it means a lot that you're willing to stand by your product. I'll take you up on your offer in the off season, when I put the car back on jack stands. It would be great if we could get to the bottom of this, and help out any others that are experiencing this issue.

I feel like it's also important to note that I am running a 4.10 final drive. Other than that though, it's definitely not improper torque as I'm VERY methodical about torque specs and all my torque wrenches have been recently calibrated. I could go under the car right now and each bolt head would still have marks from my paint pen. Didn't re-use any hardware it's all brand new, and my diff did not have balancing bolts. Subframe isn't damaged and has never been impacted by anything so I'm confident the pumpkin isn't misaligned.

I'll be done for the season around Nov/Dec, I'll follow up with you around that time frame! This testing would be done at the facility in California correct?

[JetBlack_M3]

I haven't messed with it since it started vibrating. Made sure that the balance bolt is in the right spot and tight. It still vibrates and hums badly above 140mph. Feels like all that vibration is going to snap it so I slow down..

I figured it was the guibo so I replaced it with a brand new one and issue still persists

What are the exact torque specs? Is Loctite recommend?