Not Good Vibrations
 

Whenever I go above 90mph, in any gear, even in neutral, my car will vibrate increasingly until the change pops out of my cupholder, or I back off. I changed my transmission mount, and have LCA's, panhard and all rear susp. upgrades. My tires are mickey thompson 245/40/17 drag radials, is it the tires that's causing the vibration?

your wheel balance might be off

Driveshaft, rear, wheels, tire/tire balance.

could be any or a combination of the above..... id say most likely driveshaft or tire balance.... did u just get the tires?

Ive had a similar problem like that on the highway but even at slower speeds. It turned out to be that one of my LCA's bolts broke and eventually fell out of the relocation bracket. Also an out of balanced driveshaft can cause that. Id go over all the bolts in the suspension & tires.

driveshaft.

does it feel like the vibration is coming from the front, back or just the whole entire car?

you need an adjustable torque arm, your pinion angle is way off from the trans mount.

Tire balance would be something you would feel at 60+mph or more. Driveshaft would be felt at lower then 90mph as well.
Try not driving that fast.........bwhahahahaha I couldnt keep a straight face.

go only 89 mph

You can have tire vibration higher than 60. I used to have to deal that all the time. Agreed it is not common, though.

yea you can, that's why he said 60+mph or more... Jake, why do you say that?

i say driveshaft...just had it happen to me not too long ago.

when you put a poly-trans mount in your car, your trans sits higher. a trans mounted torque arm would now be at the wrong angle (~2degrees) therefore causing vibration and wheel hop

I say take the change out of ur cup holder.

that's interesting, because when you put one in a v6 the tranny will drop about 1/2" which you need to shim up... but, I was under the impression that the V8 tranny stayed at the same height, sicne that's what the mount was designed for.

i had to shim Goofy's when i did his as well. but the vibrations it causes is nothing like the ones in the first page so i really dont know why i brought that up

Well I have a Spohn adjustable floor mounted torque arm, and an energy suspension poly transmission mount already installed, however, I have a feeling that my angles are off from when they were installed, when I have the car on a lift the other day to get subframes in, I saw something that shocked me.

At the top of the torque arm where it meets my rear end, the powdercoating was chipped and the top was mushrooming out like it had been hitting something on top of it. Sure enough I look up and on the bottom of my floor in my "tunnel" there is a big silver place in my floor that the torque arm has been smacking against and making a hole in my floor. What can I do about this? Is this uncommon?

its not uncommon at all. unfortunately the only solution to this problem is banging out the tunnel with a hammer. i assume your car is lowered

hmmm, my tq arm only went up to the tunnel once, and that was the stocker when it broke... The spohn one never gave me any noticeable issues and i was probably lower than anyone here. i'll have to check that out because now im curious...

I have 17x9 rims, lowered on hotchkis springs, with a full rear suspension setup. Hits on every big bump:(

im wondering if that "hitting" noise is a loose control arm bolt

Since my Hotchkis LCA's came with the car *97* and they're kinda rusty/old now. I'm thinking if I get new LCA's with relocation brackets that it will help it out? What do relocation brackets do? Do I need'm?