Bad Vibration in Driveline????
Thread Starter
Safety Car
Joined: May 2004
Posts: 4,811
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From: Simpsonville SC
Bad Vibration in Driveline????
I have this bad vibration while im driving. There is no whine from the rear, well at least I dont hear one. My Vette is very loud. I noticed the vibration when I put the C6 Z51 sways on. and I just installed the PFADT rear tranny brace and it seems worse. The tranny shifts fine, the clutch feels normal, and there isnt any kind of noise. Im kinda leaning toward the bushings in my torque tube.My vette has 86k miles on it and read sig for my mods. Please let me know any information or ideas. Thanks in advanced!
Bryan
Bryan
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Safety Car
Joined: May 2004
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From: Simpsonville SC
Bryan
Race Director
Joined: Dec 2004
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From: Haymarket VA
I had the PFADT tranny brace in my car for less than 50 miles. It will transmit EVERY bit of vibration that may be in the drive train. I had no noticable vib's before or after.
There are a lot of people who took it back off because of the vibration.
There are a lot of people who took it back off because of the vibration.
Thread Starter
Safety Car
Joined: May 2004
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From: Simpsonville SC
Bryan
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Bryan,
At what rpm's does it seem the worst? Can you get the vibration with the car parked,trans in netrual, clutch fully up (engaged) by slowly rev'ng? If you do, what rpm does it start and does it peak and then get less as you go higher?
At what rpm's does it seem the worst? Can you get the vibration with the car parked,trans in netrual, clutch fully up (engaged) by slowly rev'ng? If you do, what rpm does it start and does it peak and then get less as you go higher?
Thread Starter
Safety Car
Joined: May 2004
Posts: 4,811
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From: Simpsonville SC
, when i engage the the clutch it seems to go away some. I havent tried it with rev'ing it.it peaks aroun 3k and goes away at any rpms after that.....Bryan
Tech Contributor
Joined: May 2008
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Try the rev in neutral and one more important question, where do you feel the vibration? Steering wheel, seat, floor, shifter, etc..
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Thread Starter
Safety Car
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From: Simpsonville SC
Tech Contributor
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Thread Starter
Safety Car
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From: Simpsonville SC
Bryan
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Thread Starter
Safety Car
Joined: May 2004
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From: Simpsonville SC
sorry, I feel it a little bit in the shifter, gas pedal, seat, steering wheel. Its not really bad at all, i can mainly tell when im driving down the road. I had to concentrate kinda hard to see if I feel it when I rev it. Also thank you very trying to help me. Im not too good at explaining things so you might have to bare with me. Bryan
Le Mans Master
Joined: Oct 2000
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From: Oak Harbor WA
Bought a used Centerforce DF clutch with GM flywheel from a forum member and it vibrated at 1650-1900RPM and 3700-3900RPM. Tried an ebay F1 lightweight flywheel, same issue. Finally fixed when I switched over to a LS7 setup. Obviously the CF clutch was the culprit in my case.
Tech Contributor
Joined: May 2008
Posts: 2,843
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Bought a used Centerforce DF clutch with GM flywheel from a forum member and it vibrated at 1650-1900RPM and 3700-3900RPM. Tried an ebay F1 lightweight flywheel, same issue. Finally fixed when I switched over to a LS7 setup. Obviously the CF clutch was the culprit in my case.
Pro
Joined: Apr 2002
Posts: 578
Likes: 1
From: Dallas TX
So theoretically at least, what could cause an imbalance in an engine/driveline which is guaranteed all original?? Excuse me, more specifically a first order imbalance??
Not trying to be a smart a**, simply trying to understand what is happening to my car
Thanks
-Ed
Not trying to be a smart a**, simply trying to understand what is happening to my car
Thanks
-Ed
Tech Contributor
Joined: May 2008
Posts: 2,843
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Here is a couple of ways to think about vibration. I will focus on 1st order imbalance, but keep in mind there are many modes of vibration besides 1st order. 1st order happens when a component has more mass on one end compared to the other about the rotation center. Just about any rotating component will have some amount of imbalance. It really isn’t an issue unless this vibration transfers to other components. The Corvette has a very unique powertrain compared to most vehicles. So, the second part of this is the transfer of vibration. The primary reasons for engine and transmission mounts that can move are to isolate powertrain vibrations from transferring into the vehicle. Designing the powertrain mounting system is a big deal. It takes a lot of work to get it right. Changing mounts to something different than stock will buy you little or nothing in performance and in most if not all cases will degrade vibration isolation.
I don’t know the detail of your vibration. You mentioned your car is stock. Do you know if your vibration is powertrain related? Just about anything that rotates could be a source, like wheels, tires, brake rotors, hubs, etc..
Pro
Joined: Apr 2002
Posts: 578
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From: Dallas TX
Car is completely stock save a shifter, blackwing and Ti mod exhaust. The vibration seems independent of speed, but dependent on RPM starting at around 2K and ending maybe around 2.5K. Usually felt in the pedal, kinda the seat. Really hard to know for sure, it is almost like my bat-sense is telling me it is there.
Now, on the completely stock list, I will say that I am getting some inconsistent hesitation from the motor and have plugs and wires on my to do list. I was thinking this might be part of the source, but hadn't gotten there yet. At 47K over 8 years it has not been driven a ton until recently when the AC on the normal DD died and I survive (barely sometimes) down here in Houston.
Thanks for your help
-Ed
Now, on the completely stock list, I will say that I am getting some inconsistent hesitation from the motor and have plugs and wires on my to do list. I was thinking this might be part of the source, but hadn't gotten there yet. At 47K over 8 years it has not been driven a ton until recently when the AC on the normal DD died and I survive (barely sometimes) down here in Houston.
Thanks for your help
-Ed
Tech Contributor
Joined: May 2008
Posts: 2,843
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Car is completely stock save a shifter, blackwing and Ti mod exhaust. The vibration seems independent of speed, but dependent on RPM starting at around 2K and ending maybe around 2.5K. Usually felt in the pedal, kinda the seat. Really hard to know for sure, it is almost like my bat-sense is telling me it is there.
Now, on the completely stock list, I will say that I am getting some inconsistent hesitation from the motor and have plugs and wires on my to do list. I was thinking this might be part of the source, but hadn't gotten there yet. At 47K over 8 years it has not been driven a ton until recently when the AC on the normal DD died and I survive (barely sometimes) down here in Houston.
Thanks for your help
-Ed
Now, on the completely stock list, I will say that I am getting some inconsistent hesitation from the motor and have plugs and wires on my to do list. I was thinking this might be part of the source, but hadn't gotten there yet. At 47K over 8 years it has not been driven a ton until recently when the AC on the normal DD died and I survive (barely sometimes) down here in Houston.
Thanks for your help
-Ed
If the car was fine and then all of a sudden started to have vibration issues I think you maybe on the right track looking at plugs, wires, injectors and maybe even running a compression test.
If you have an engine 1st order imbalance it will show up just rev'ng the engine with the clutch pedal pushed in. If you only get the vibration with the clutch out and the trans in neutral it could be the clutch disc, or something with the propshaft. If it only happens while rolling down the road, could be output shafts, tires or wheels.
