Observation and question about high speed (85-180mph) really tight vibration.

[viper04]

Sorry to hear this, was hoping you were going to say you found the problem after all this time.

[TrackAire]

Well that sucks.

Have you taken the car up to 110 mph or so and lightly apply the brakes and see if that lessens the vibration?

Also, maybe take the car back up to speed and apply the parking brake 1 or 2 clicks and see if that lessens the vibration. This may help rule out the brakes/rotors as being the cause.

I'd also really take a good look at the rear bearings and make sure they are all good and torqued correctly (IIRC it's something like 300 lbs).

Don't give up, you'll get it figured out.

[CarolinaViper]

Had the same vibration in my 71 Plymouth GTX (Auto Transmission), I started withed replacing U-joints, balancing drive shaft (three times) replacing wheels, harmonic balance, water pump, rear end a few other suggestions that I can't remember...finally went away when I replace the torque converter...I know my GTX is an auto vs a manual but my vibration was transmission related. Don't know if this helps or not.

[Jack B]

I believe it was stated that it is linked to speed, not, rpm. That rules out clutch/flywheel.

Had the same vibration in my 71 Plymouth GTX (Auto Transmission), I started withed replacing U-joints, balancing drive shaft (three times) replacing wheels, harmonic balance, water pump, rear end a few other suggestions that I can't remember...finally went away when I replace the torque converter...I know my GTX is an auto vs a manual but my vibration was transmission related. Don't know if this helps or not.

[ViperSmith]

I have to wonder if it is a buffeting issue as well. Silly enough, could you block up the rear side intakes behind the doors and see if it stops it? I wonder if the tubes are pushing air somewhere and causing a resonating frequency

[Jack B]

It did the same on a dyno

I have to wonder if it is a buffeting issue as well. Silly enough, could you block up the rear side intakes behind the doors and see if it stops it? I wonder if the tubes are pushing air somewhere and causing a resonating frequency

[XSnake]

Have they tried balancing on different machines? I've seen variations between machines, especially older or heavily used ones.

[Jack B]

I believe it had the issue on the dyno.

Dang ya I was thinking the same thing. I did check and recheck the front and rear wheel wells and the brake cooling stuff behind them. I also checked and retightened the rear diffuser hardware.
Gonna borrow a set of rear wheels and tires and if that doesn't she'd some light then hit the dyno for a quick pull. I'd like to get a baseline before mods start anyway.
The wind buffeting thing could definitely be the issue. Thanks again all!

[ViperSmith]

It did the same on a dyno

ah missed that part.

[triblk6spd]

Thanks guys. Yep. Dyno...problem still there. I tried new wheels and tires as well as rebalanced everything. We ran it up yo 90mph on the lift yesterday as well. You can feel the vibration all over the rear end....seems equal on both sides. Sooooo frusterated.

[esm_viper]

I've been following this thread and trying to remember my experience with something similar with a 2002 Z06. I went the the same process you've gone through except I didn't touch the driveshaft and half shafts. Here is a copy of what I posted years ago.

Just wanted to post up my experience with a vibration that I was having over 80mph. Long story short, I balanced the wheels and replaced a bent wheel....the vibration was still there. Noticed there was uneven wear on the tire that was on the bent rim, so I replaced the shocks (car has 75k miles)....vibration still there. Got the car up in the air, I was able to wiggle the rear wheels back and forth, so I replaced the tie rods...BINGO! No more vibration. So for those who have a vibration and can't figure it out, check the tie rods first!

http://www.corvetteforum.com/forums/...xperience.html

[drueherl]

I would look real hard in to those rear brake rotors. Like TrackAire said get to 110 or so and lightly apply brakes. Only thing I can think of to add is don't let off gas, keep foot steady on gas and apply brakes lightly.

Worth shot... Easy test to rule out rear brake rotors being slightly warped.

[triblk6spd]

Ok. I'll do that. The vibration is definitely not on one side or the other. Seems weird that both rotors would be off.
Definitely try today tho.

[Jack B]

If that isolates the issue, it could be the rotors, or a bad bearing. This points more to a bearing, since a bearing vibration is not a resonant vibration.

Ok. I'll do that. The vibration is definitely not on one side or the other. Seems weird that both rotors would be off.
Definitely try today tho.

[triblk6spd]

Updater: Nothing today. No email from the field "expert." I love how these guys sit around and wait for emails from each other instead of having a real conversation ton decide how they might be able to fix my ongoing issue. So sad.

On a better note...my new wheels will be here Friday...*that I really have no use for until my car is running like it should.

[EZ 2B Green]

Well...NOT the driveshaft. Shit! Dealer is gonna try to get in some sort of electronic contraption that measures vibration and frequency.
Halfshafts are 3-5 days out. TX2K15 isn't looking too good.

In the old days they used a reed tachometer mounted to the inside of the windshield to get this information. The electronic version should get the same results. The frequency of the vibe, speed, tire diameter and RPM should point to a limited number of possibilities. These should be able to be eliminated one by one until the source is found. You already eliminated several possible sources. Using the data it seems that it should point to the culprit by now. Did they get this data yet?

[04 mamba]

Did you ever find the reason?

[gmiles]

any answer yet?

[Rapidrezults]

It was said to be resolved in another thread and driving fine after the diff replacement.

http://driveviper.com/forums/threads/7709-Has-anyone-else-had-to-deal-with-SRT-and-the-awful-warranty-department-Not-fun!/page3