interesting on the tires...... I have brand new PS2s but I did beat the crap out of them at the track.... I will have the shop take a look.

 

At the driving course my buddy took they would go through a set of Super Sports in only a couple of days. It's at least a possibility.

 

Just picked up car from shop.
Fluid was fine
Steering gears and box were fine
U joint was fine
Tires appear fine
Put car on rack and it was perfectly in line

Drove home and still felt sloppy above 75mph. It only happens at higher speed. Steering is normal at low speed. What changes progressively with speed on the car??

A bump steer kit was recommended since the car is lowered on H&R with stock tie rods. Could this help?

 

wow, never seen anything like this and I cant believe a fix has not been found! Have you taken it to a dealer? I know, I know, stealerships...but might be worth a try.

 

Im having this EXACT same problem with my 996TT and it is getting frustrating trying to figure it out. One person told me that everything checks out fine and another says the rack itself is bad, I have no leaks either..

I too would love to have this fixed...

 

Wouldn't the camber change with lowering springs? Does your car tend to follow grooves on the road at 60mph and above?

 

Not sure if that question was meant for me or Pace however I also had the alignment done and had wheels re-balanced.. She tracks straight but get very loose at higher speeds just like in Pace's video.

 

Do you happen to know your camber degree? Is it aligned to stock specs or something more aggressive?

 

Sorry, I think you both are having the same issue. So the question works for both.

 

Unfortunately I don't know the camber degree, the shop that installed my suspension originally set it up for the track however I thought that it would be too harsh on the tires since I am mainly driving on the street and get to the track only once a year.
They supposedly re-aligned the car and set it up less aggressive.

 

I would contact them and see if they have it on record. It may be a good question to them at that time also.

Did you see a improvement after they made the last adjustment?

 

Unfortunately there was no improvement in high speed stability however the low speed road handling definitely improved..

 

Did you get a before and after printout of the alignment settings?

I hate to suggest this but it has happened and that is the alignment wasn't checked or set.

If the tires are properly inflated and if the alignment is correct and if the car is stock -- has all its factory installed aerodynamics present -- the car should feel extremely stable at speed.

(I've had my stock 996 Turbo up to 165mph and it felt just fine. Impressively stable automobile at high speed. I would expect the 997 Turbo to be at least as stable if not more so.)

If you have modified the car, its aerodynamic features with aftermarket items, or have removed factory items, I would hazard a guess this could be a contributing factor.

Couple of things. Be sure all 4 tires are correct, have the same N number, are the correct size, the same load rating, speed rating, tread hardness, etc. Be sure if they are uni-directional they are mounted in the right direction.

If from the above you find no smoking gun, I'd be inclined to take the car to another shop for a full alignment and be sure before you have the work done you will get a before and after printout of the alignment settings.

Just a heads up: If the car has been lowered the stock suspension may not have enough adjustment to align the car to the stock settings.

But the shop should tell you this and then you can explore what aftermarket suspension hardware you will need to have fitted so the car can be properly aligned.

 

I think the concern is he is turning the wheel about 30 degree and the car isn't moving left or right at all....it is like he is driving an old RV with a worn out steering rack

 

Take the car to the dealer and have them look. I had this same exact problem on a different car. I replaced the steering box, same problem. Then replaced u-joint and got an alignment and that fixed the issue.