Unaligned at high speeds

[AIB]

I have a 2005 997 CS2. When I hit speeds above 120 km/h I feel the car does not go in a straight line and actually feel I have to force the steering wheel into staying in a straight line. The car doesn't crazy left and right but its just not straight and just floats a little to the left then a little to the right, thats when I have to intervene (the steering wheel actually gets heavy to a certain side even though obviously I have my hands on it). Sent it to the dealer and asked them to check it out. They said the wheel alignment is perfect and that the springs are good and that there is nothing wrong with the car.

After getting it back I was starting to think that I was just being paranoid. A few days back I hit the high way and I could swear the car was not going in a straight line and I had to constantly keep it in a straight line.

Some one told me it might be the control arm or something? any suggestions?

Thanks

[White987S]

How are your tires? Mileage? Tire pressures? Wear?

What are the road conditions like in your part of the World? Are the roads sloped for drainage/run-off?

[AIB]

How are your tires? Mileage? Tire pressures? Wear?

What are the road conditions like in your part of the World? Are the roads sloped for drainage/run-off?

I have Pirelli Pzero Tires with only 2,000 km on them. 19 in rims. Front tires at 24 pressure and back tires 29 pressure. The roads suck in my city. Very uneven roads.

I have driven other sports cars on the roads in my city and they aren't as un aligned as my porsche.

[355bhp]

I have Pirelli Pzero Tires with only 2,000 km on them. 19 in rims. Front tires at 24 pressure and back tires 29 pressure. The roads suck in my city. Very uneven roads.

I have driven other sports cars on the roads in my city and they aren't as un aligned as my porsche.

If you've got a decent tire pressure gauge, check the current pressures yourself; the dealer may have fluffed up the tires to the spec pressures, which are about 10 psi more than your usual settings. With the 35 aspect ratio of the S's tires, I don't think 10 psi will affect the ride much. And make sure it's off the sport or PASM setting; mine rides like an old Morgan +4 when I hit the little button with the Koni shock icon.

[nastinupe1]

It's the roads. Your tires are simply following the road grooves. It happens with high performance tires. They are very sensitive to the conditions of the road. That's why driving an Accord seems easier than driving a Porsche.

[AIB]

Thanks a lot guys. Now I can sleep better at night.

By the way I'm loving the CS2 997, great sports car, just wish I could get it on the track. Unfortunately there's no tracks in my country.

Anyone tried out the porsche track experiences or travel club? anything worth signing up for?

[nastinupe1]

Thanks a lot guys. Now I can sleep better at night.

By the way I'm loving the CS2 997, great sports car, just wish I could get it on the track. Unfortunately there's no tracks in my country.

Anyone tried out the porsche track experiences or travel club? anything worth signing up for?

If I were you, I'd just hang out at the dealership and find about 3 -4 guys who want to go driving on the weekend. That's always free.

[997onthebrain]

I have played with the tire brand/pressure/nose lift/camber issue on a 2008 C2S for several months. The Pirelli's are very noisy and hard riding. After 7000 miles on the odometer I put them in the dumpster. The PSC2 from Michelin are far superior. Not only are they quieter and better riding, the adhesion is amazing. To get the car to drift now, I really have to push it. I keep the pressure slightly under spec, 34 fronts and 40 rears, Nitrogen only. I do have front end motion at speeds over 120 miles per hour, mostly vertical (some horizontal, I attribute most of this to thrust lift). Once I hit fifth gear on the S (126 MPH) the car settles a bit thru 150-155. Even then however, the car "feels" a little nervous at that speed. Like yourself, I remain a bit puzzled by the motion and will consider alignment adjustments as I am sure tire pressure/balance/size and brand are not the issue. Best of luck.

[PAULSPEED]

You may want to look into getting your car aligned for

track use. The stock set up would want to push. I

would get the car up to 120-130MPH and slam on the brakes. I

would then turn the wheel and accelerate. The car would still

go straight. I had the car aligned for track use.

The car is not perfect but it is a whole lot better. When I brake and

then turn the car behaves.

To make a real fast lap, I have to start the turn just a little bit before I am finishing

braking and then accelerate thru the turn.

I should not be giving out my racing secrets!!!

Paul

[AIB]

I have played with the tire brand/pressure/nose lift/camber issue on a 2008 C2S for several months. The Pirelli's are very noisy and hard riding. After 7000 miles on the odometer I put them in the dumpster. The PSC2 from Michelin are far superior. Not only are they quieter and better riding, the adhesion is amazing. To get the car to drift now, I really have to push it. I keep the pressure slightly under spec, 34 fronts and 40 rears, Nitrogen only. I do have front end motion at speeds over 120 miles per hour, mostly vertical (some horizontal, I attribute most of this to thrust lift). Once I hit fifth gear on the S (126 MPH) the car settles a bit thru 150-155. Even then however, the car "feels" a little nervous at that speed. Like yourself, I remain a bit puzzled by the motion and will consider alignment adjustments as I am sure tire pressure/balance/size and brand are not the issue. Best of luck.

After getting around 2,000 km on the tires and drifting a little in them (treading them out) the car does drive better. However I think I will do exactly what you did and throw them out after getting a few more thousand kilometers on them. Thanks a lot for the great input and advise.

[AIB]

You may want to look into getting your car aligned for

track use. The stock set up would want to push. I

would get the car up to 120-130MPH and slam on the brakes. I

would then turn the wheel and accelerate. The car would still

go straight. I had the car aligned for track use.

The car is not perfect but it is a whole lot better. When I brake and

then turn the car behaves.

To make a real fast lap, I have to start the turn just a little bit before I am finishing

braking and then accelerate thru the turn.

I should not be giving out my racing secrets!!!

Paul

Thanks for the racing secrets bro, I promise not to tell anyone ;)... Will find it difficult to get the car aligned for track use since in Lebanon we dont have a race track, so I dont think I can find someone to align it for track usre :).... Hopefully in the future we can get some investments together to get one started until then I'll have to do with what I have. I'll give my dealer a call and see if they can do such an alignment for me.

[PAULSPEED]

I actually had my dealer do this. He had a guy at his shop

that was into this. The lower a-arms come apart and he

put very small shims in them.

Paul