O.k.
Took the car yesterday for the first turbo drive and noticed that under load at 4th gear I get a mean vibration in the car

Could this be the drive shaft???

By the way that GT35 pulls like a mad beast

 

is your car lowered? its most likely the common problem with the axle buckets.

 

Possibly. But if it wasnt there before then I would double check clearance on exhaust, down pipe, radiator/intercooler mounting or anything and could be contacting the body to cause a vibration. Maybe see if you can get your car on a lift and see if you can get it to happen on the lift while inspect the car.

 

I agree based on what I've seen in the past on this board (and personal experience).

 

I know its way worse when you are pushing some power.

 

Great information, do you think you should maintain reg stock height when pushing higher power. Could you do say eibach springs and be OK.

 

The car is NOT lowered
nothing is touching (exhaust, d. pipe, radiator cooler all is fine)
Just a mean vibration when accelerating in 4th gear

 

Are you still on the stock rearend and axles?

I'm wondering if 4th gear has something wrong with it? Does it do it in any other gears; 3rd, 5th, 6th?

 

mine wasnt lowered either. Just a good amount of miles.

 

does it feel like you're driving over cobblestone? I agree that its a good chance that it's the axle buckets. You can swap them for free or pay ~$100 for 2 piece driveshaft spacers (i bought mine off ebay as one piece and cut them in half) and installed them in about 30 min. smooth as silk. At least until the buckets get pitted again at which then, I'd swap them.