Major Vibration Issues - Help

NOBLE|370Z

Folks

Today I went for a nice calm spin around town. After about an hour of driving suddenly when cruising at 80km/hr my car began to vibrate significantly. There is a deep bass sound that goes in and out with high frequency. It's more noticeably after a take off the gas and coast. When I give it throttle, it goes away mostly. Therefore, I believe that it is something rotational. I don't believe it's the engine, or the wheels/suspension. When I pulled over to stop, I gave the car a few revs for a couple of minutes, and the vibration was not present. I had an alignment done on my car recently as well, so I don't believe it's the wheels.

My 370Z MT TT has been boosted for about 10,000km. Due to the OEM clutch slipping on me, recently I upgraded it about 1000km ago. I went through Joe at Z Speed Performance and bought/installed the Southbend complete stage 3 clutch package. I have a feeling that the vibration has to do with the clutch...

The reason why I think so is that I read a recent thread here by JoePro that outlined a problem with a similar vibration issue, and he was able to conclude that the new pressure plate on his southbend clutch kit broke. However, when I compare the symptoms between his experience and mine, I notice that his car vibrated when it was parked or up on a lift. Therefore, the issue may still be outstanding here...

There has only been one other event that may be linked to this. About 80km ago, I was pushing the car hard (10psi), and when I let off the throttle to slow down there was an immediate bang sound, which I believed was only backfire. Other than needing to update my tune, I don't think that has anything to do with this. If I broke the motor, then I'm sure the ECU would have thrown a code by now...

Does anyone have any idea what is going on? I appreciate your feedback.

Plasmite

If you're backfiring that is something that should be looked into immediately anyways....

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NOBLE|370Z

Yes I agree. Its back fired only once so far on the GTM canned tune. I'll take it in to a shop to have them work off of GTMs tune. Thank you for the feedback for that.

MacCool

Especially if it didn't throw a code, I'd bet on driveline...clutch, pressure plate, or flywheel.

Trips

Vibrations can come from anywhere like from an unbalanced flywheel/clutch, loose driveshaft, bad u-joints, rearend, loose or out of balance wheels.

Have everything looked over carefully before it get worse.

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NOBLE|370Z

Yeah not sure it's clutch/Pressure-plate. It's not rpm dependent. It's more speed related. Clutch pressed in or out if I rev up to 4000 rpm parked there are no vibes. When they installed the clutch could they have thrown something loose in the drive shaft or u joint somehow?


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NOBLE|370Z

I took a video underneath the car of the rear drive shaft, next to the rear wheels, so that you can all see where the vibrating problem could be originating from. I have the car up on jack stands and I take it up to 80km/hr where it starts to get really bad. Notice the noise it makes as it slows down near the end as well.

https://www.youtube.com/watch?v=IhIE...ature=youtu.be

Any thoughts? After the clutch kit was recently installed could the problem be because my mechanic didn't aligned the drive shaft properly? Propeller shaft run out tolerances?

By visual inspection the drive shaft appears to have all of the nuts and bolts tightened down effectively. I guess I'll need to take it to the Nissan dealer to have the drive shaft serviced...

1slow370

did you check for play in the u joint? if the car is in the air just grab the driveshaft and the front diff flange and twist them opposite ways back and forth to check for slop in the joint. if you have slop you need the u joint replaced.

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Plasmite

This. Also, don't have the car running when you check :P

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Plasmite

I can't hear the video, but by the looks of it the vibration seems to be coming from the tranny...the mounts flex quite a bit. I'd take it back to your clutch guy and have him take a look at it. He missed something

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Plasmite

Take a video of where you are placing the camera then run the car. Need a longer video and need to see more of the underside of the car. Especially the tranny.

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1slow370

you cant even see the trans in the video? I don't think it's trans just sound like a sloppy u joint.

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Plasmite

He said the view is the driveshaft going into the rear diff. I would like to see the driveshaft from the other end

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DOOMMONKEY777

Sounds like bearings gone bad...ur lsd bearings...somewhere on ur pumpkin's bearings gone bad or bad lsd or u lost a shaft or clutch screw that gives u unbalance. My 2cents <-not a car pro

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NOBLE|370Z

Here is a video of the transmission side of the drive shaft:

Nissan 370Z Drive Shaft Vibration - YouTube

The car is going into the shop where the clutch was recently installed. The mechanic will look at the u joints, and the drive shaft. As well, he should be able to check on the transmission position.

Hopefully it's just minor, and it's not the LSD or anything significant. I'll keep you guys posted - thank you all for your comments!