DSS one piece driveshaft vibration

[Wanganstyle]

Even more! Local's car we worked on until he went 2j was making 518whp/550wtq with a bone stock OE shaft from 1988 - not even a rebuilt unit.

In the 2jz world the solution for 1krwhp range supras was always to just re-tube the Oem 2 piece driveshaft

[ForcedFirebird]

Solution to problems is:

Install Oem Bmw 2 piece driveshaft.

350-400hp is not a problem.

Even more! Local's car we worked on until he went 2j was making 518whp/550wtq with a bone stock OE shaft from 1988 - not even a rebuilt unit.

[Wanganstyle]

I got the one piece because I broke the stock one. It's pushing somewhere around 350-400 at the crank.



More to this story. I swapped rubber motor and trans mounts in and reinforced the subframe. DSS agreed to rebuild it with a CV joint. They got the measurements wrong the first time for some reason and I had to send it back because the CV eliminates the slider... Has to be exact length to ~1/2". Dropped the second one in and it vibrates at higher speed now. Becomes very noticeable at 80, really bad at 100; didn't want to go any higher. I've asked for a refund but who knows at this point. In the past two years I've put maybe 200 miles on it because of this issue. If they decide to refund me I'm putting the stock one back in for a while. If not, I'm stuck with a $1000 paper weight.

Solution to problems is:

Install Oem Bmw 2 piece driveshaft.

350-400hp is not a problem.

[JimmyP]

The basic solution to your problem was was back in 2017:

One piece driveshafts like equal and opposed angles in one plane only. If you have angles in two planes that very possibly could cause your situation.

An E30 drivetrain from crank to diff input is straight and sits in the car at an angle left to right. The front of the crank is biased toward the drivers side and the diff input is biased towards the passengers side. The driveshaft hits the diff at an angle horizontally.

Rotating the engine and trans assembly on the horizontal plane should allow you to get equal and opposed angles in the horizontal plane , but raising the diff straight up would introduce compound angles which could vibrate.

The only way to eliminate a horizontal angle would be to rotate the diff horizontally so the input pointed directly at the tail of the trans, which it does not do from the factory.


The factory 2 piece driveshaft is extremely forgiving....

I have a 1 piece driveshaft in my race car because I went to a T5 transmission.
I had loads of vibration issues until we sorted out the equal and opposing angles.
There is not much realistically you can do to the clocking described above in the quote, but you can mitigate it alot by shimming the diff angle vs trans output shaft angle to make those equal and opposing in the vertical plane.
Mine is now happy to top of high gear, I can feel just the slightest hint of vibration at high speed in 5th gear just oncoming, but its nothing even remotely like it was.

[mohmoh62]

I got the one piece because I broke the stock one. It's pushing somewhere around 350-400 at the crank.

More to this story. I swapped rubber motor and trans mounts in and reinforced the subframe. DSS agreed to rebuild it with a CV joint. They got the measurements wrong the first time for some reason and I had to send it back because the CV eliminates the slider... Has to be exact length to ~1/2". Dropped the second one in and it vibrates at higher speed now. Becomes very noticeable at 80, really bad at 100; didn't want to go any higher. I've asked for a refund but who knows at this point. In the past two years I've put maybe 200 miles on it because of this issue. If they decide to refund me I'm putting the stock one back in for a while. If not, I'm stuck with a $1000 paper weight.

[moatilliatta]

I've heard these causing vibrations.

Can you put the stock one back in?

[iwantspeed]

sounds like the solution to all your problems is to put the diff back in the stock location and buy a

bmw 2 piece driveshaft

new u joints

center support bearing

new guibo

[mohmoh62]

Well. The subframe bushings were upside down. The spacing I put in there for the diff was supposed to bring it back to oem alignment with trans. Instead it was putting it even lower. I pulled the rear subframe after work and am going to flip those bushings, maybe do some cleanup on everything. I would imagine this has caused all the problems the past couple years. Just never really noticed til the one piece went in.

Nope. New diff bushings, new subframe bushings, no change. It starts vibrating bad around 90.

[mohmoh62]

Well. The subframe bushings were upside down. The spacing I put in there for the diff was supposed to bring it back to oem alignment with trans. Instead it was putting it even lower. I pulled the rear subframe after work and am going to flip those bushings, maybe do some cleanup on everything. I would imagine this has caused all the problems the past couple years. Just never really noticed til the one piece went in.

[TobyB]

Have you checked the diff input flanges carefully to make sure they're not bent?
(I noted you used 2 different diffs)
I've chased my ass on those more than once.
It doesn't take more than a few thou of runout to cause problems, and it's pretty easy
to bend a flange when the diff's floating around loose.

Other than that and the trans flange and pilot nose... I got very little...

t

[LJ851]

I ordered it from DSS.

http://www.driveshaftshop.com/import-driveshafts/bmw/bmw-e30-1986-92-1-piece-chromoly-driveshaft

I live 12+ hours away.

They said to try rotating it 180 degrees. Didn't help. Said they'd recheck balance if I sent it back, which I intend to do, but I don't think that's the issue. Rotating it with respect to the adapters should've caused the frequency to change. The variables should do nothing to the alignment of the transmission and differential. As long as they're parallel, it shouldn't matter. I guess that's what I'm asking; is there something that could be causing the alignment to be off that I'm not aware of? Or any other ideas?

One piece driveshafts like equal and opposed angles in one plane only. If you have angles in two planes that very possibly could cause your situation.

An E30 drivetrain from crank to diff input is straight and sits in the car at an angle left to right. The front of the crank is biased toward the drivers side and the diff input is biased towards the passengers side. The driveshaft hits the diff at an angle horizontally.

Rotating the engine and trans assembly on the horizontal plane should allow you to get equal and opposed angles in the horizontal plane , but raising the diff straight up would introduce compound angles which could vibrate.

The only way to eliminate a horizontal angle would be to rotate the diff horizontally so the input pointed directly at the tail of the trans, which it does not do from the factory.


The factory 2 piece driveshaft is extremely forgiving....

[jlevie]

Bad transmission or motor mounts could affect alignment, as could a damaged subframe.

[mohmoh62]

Seems you have changed loads of variables so you are way off OEM specs.

Have you taken the car back to who made the 1 piece driveshaft with it installed and got them to have a look at your setup?

I ordered it from DSS.

http://www.driveshaftshop.com/import-driveshafts/bmw/bmw-e30-1986-92-1-piece-chromoly-driveshaft

I live 12+ hours away.

They said to try rotating it 180 degrees. Didn't help. Said they'd recheck balance if I sent it back, which I intend to do, but I don't think that's the issue. Rotating it with respect to the adapters should've caused the frequency to change. The variables should do nothing to the alignment of the transmission and differential. As long as they're parallel, it shouldn't matter. I guess that's what I'm asking; is there something that could be causing the alignment to be off that I'm not aware of? Or any other ideas?

[e30davie]

Seems you have changed loads of variables so you are way off OEM specs.

Have you taken the car back to who made the 1 piece driveshaft with it installed and got them to have a look at your setup?

[mohmoh62]

Tldr?

Figured I should be thorough. tldr driveshaft vibrates for no reason. Help me.