when i hit about 95mph ish my car vibrates pretty decently... one of my buddies suggested changing the U joints... is that it?

 

Could be U joints but they usually vibrate a throughout the speed range. It could be several different things. Transmission mounts, driveshaft balance, wheel balance, tire wear or shock hop. Where does it feel like the vibs are coming from, front or rear? You can lift the car, block the wheels, put it in neutral and grab the driveshaft to see if there is any side to side or up and down motion. If so, then you could have universal joints dry and going bad.

 

Under load or all the time? Under load then yes that is one of the things it could be that. If it is all the time (even when you are off the throttle) it is probably something out of balance or a slight bend in a wheel or axle.

You may already know this but FYI:
Normally we call a car the vibrates at a certain speed regardless of the load on the motor a vibration and a car that vibrates at a certain speed only while on the throttle a shimmy.

 

yeah it does it with just me in the car and it happens when i am on the throttle and off... when i hit that speed that it vibrates if i let off the gas and pull her out of gear and just let her coast it still does it... im pretty sure its not the wheels cause i just had those replaced... and yeah i do know that the car vibrates but it feels like its coming all from the back end...

 

Is this with slicks or drag radials because at 95mph this is on the track, correct?

If it's with your street tires and on the track, it may be something as simple as a wheel balance or even a tire is worn funny. I've replaced tires with plenty of "meat" still on them just to get rid of noise and vibration. If it's with slicks or drag radials, then is it really that bad? At 95mph, you don't have much further to go until you cross the finish beams.

 

no its with normal street tires on the road... and i replaced the tires and it still does it... i do however have a tire balance problem now that i put new tires on it but it still vibrates really bad when im at that speed whether it is in gear or not!

 

i had that problem in the z28 and it was one tire had a defect in it. another time a while ago in a truck i had it was a little bend in the rim but it vibrated at 50.

 

sorry, I'm out

I'm a dad and when i was a young pup, I lost friends who were "the best drivers in the world" yet lost their lives because they drove too fast. Please take it to the track if you have a need for speed and keep my 3 kids who drive, safe and sound. Your mom and dad would probably appreciate it too.

 

yes i do know that if i have a need for speed i do need to take it to the track but im not going to drive an hour to run it every time i have to tune it or want to go fast... but that still doesnt fix my problem... so craby are you saying it could possibly be the rims or tires and not the u joints? or something else?

 

yes i would look to the driveline also but it would be good to try a balance on the tire and rim. best way is on the car but i dont know if shops still do that. in shop (back in the 70s) for the back we use to jack the rearend up with the axle lift and run it up to 70 or 80 to check drive train ballance at high speed. not a good thing to do on jack stands though. lol at least not in the garage.