997gt3north

do you have any aftermarket front suspension pieces on the car?

Texas RS

Before-----
Front
Ride height: 104mm
Camber: -1.8
Toe in: -1.6mm
Caster: 8.0 (don't have print out - verbal from mechanic)

Rear
Ride height: 137mm
Camber: -2.2 deg
Toe: 4.6mm

After

Front
Ride height: 100mm
Camber: -2.12 deg
Toe: -2.2mm
Caster: L: 7.25. R: 6.86

Rear
Ride height: 125mm
Camber: -1.7
Toe: 4.1mm

I don't have the conversions from mm to degrees, it was just what was on the print out.

Texas RS

Car is completely stock except for wheels and now the setup....

997gt3north

- i find it hard to believe, but I am not an expert in caster, that what he has told you is remotely the truth

- the 8.0 caster is the Porsche OE spec (I'm guessing this is why he stated this number)

- so what he is trying to tell you is that by adjusting the eccentric from the top (I'm guessing he did not use shims because you did not provide them, they weren't in stock and he may not actually know about them) that by adding -0.3 camber from the eccentric in the front he dropped your caster by over 1 point? (no way - if I'm wrong I apologize but no way)

- I do not want to imply that this is causing your pulling issue - I just want to point out that the above does not make sense

- the fact that you are at -2.1 in the front, I'm guessing that you gave him a number that you wanted and he came back and said this is all I can do (which is correct if he is using the eccentric only, did not rotate the struts and did not use shims)

- since you have gone with -2.0 in the rear, my guess is that you wanted (or should have wanted) -2.5 to -2.8 in the front and -2.1 was what he could give you as he was unprepared or did not know what to do

- if you were going to keep stock ride height and stock 235 tire size in front, then shimming the LCAs is the way to go
- if you drop the front ride height, want to run a 255 Hoosier then if you are getting rubbing (no 2 cars are the same) that is when rotating the front strut and then shimming the LCA to bring the camber from 'around' -2 up to -2.5 to -2.8 is the way to go because once you rotate the strut it reduces your caster to the low 7s (typically) if you then start adding shims to get you the camber you want the positive byproduct is that you increase your front track and caster also gains as well

- if you are trying to squeeze a huge front tire in there, then that is when you start to use some shims and some eccentric to basically make it fit (do what ever is required with your given rim offsets etc)

- just want to re-iterated that I'm not saying that the tire that blew up didn't cause damage but something else is not adding up (I could be wrong but I just don't believe your caster dropped that much by adding -0.3 camber in the front)

- what i personally would do is drive the car out of there, purchase a shim stack, bring it to a race shop and have them set up the car to -2.5 front with zero toe and have them do ALL of the front camber adjustment with shims (fine tune only with the eccentric) and then see where your caster gets to and see if you still have the pull

good luck

Texas RS

You are correct on the 2.1 camber on the front, it is the max without shims (they didn't have any)

Since I only have 19" wheels, I have been running 235s on the front as the next size are 265s and they rub. I have not had any rubbing issues with the 235s. Additionally, I have not taken the car to the track with this setup - a little concerned too at this point.

One clarification, the front tire did not blow only a single bead wire started working its way out of the sidewall and that tore up the boot. I have seen this three times on Hoosier R6s.

997gt3north

those 19" 235 hoosiers are a very wide 235 tire and good fit for the car - I have also run them a few times

i'm now looking at your picture and see you on a banked oval - I have only run those tires in the North on road courses and don't have experience with how they wear under those conditions

i remember some discussion, maybe about 2 years ago, about tires on those highspeed banked ovals and I do remember 'something' was happening to certain tires

since you were not pulling to the right before this new alignment, doesn't mean everything was well, but it doesn't mean it all needs replacing either - but when I tire blows up 'stuff' does happen but it is usually body work and soft stuff like has happened to you

Easier things to try:
- swap the front tires L&R and see if it is still happening or put on a different set of wheels (not R6s but street tires)
- are you sure your rims are straight (at Watkins Glen last year I bought some tires off a rennlister and had to have a bunch of tires swapped to make the deal happen) one of his expensive aftermarket Center Lock rims was bent and he did not know about it (my guess was from pounding curbs)
- before I spent the money to fix the problem, I would like to know that the geometry of the OLD alignment was indeed accurate (i.e. at the factory ride height and factory front camber you know the car was straight but are the castor values close to 8.0
- they lower you car and then it started to pull - coincidence? - no - are your fender to grounds on each front corner the same?
- does it pull at 15mph and at 50mph
- is it pulling with the Hoosiers and with toe out when they took it for a spin after the alignment or with your OE street tires?
- with your caster values that different and with toe-out that is likely your issue right there - go back to 1/64 total toe-in and see if that works but also order a couple of shim stacks and have them widen the front track for better turn-in feel - it will also bump the casters back up
- if you want to equal your casters and your particular car needs help, order the tarett adjustable thrust arms

good luck, these little things can drive you crazy

http://www.tarett.com/items/996-997-...010-detail.htm

Ur20v

fitting the top strut mount 'wrong' is easy, as you swing the strut in it can spin and if not double checked it might have been fitted different either side. hard to tell from underneath.

Jay

LehmanZ06

How were you given the toe measurements ?
Can you post a picture of your alignment print out ?

I would always ask for a before and after alignment print out.

I might consider getting the car aligned at another dealership quite honestly.

LehmanZ06

Look at the strut tops and check that they are identical on both sides of the car.
Same holes used.

Texas RS

997gt3north,

Just for clarity the tire did not blow, it didn't even lose air pressure, there was just a single bead wire that worked its way through the sidewall.

In regards to the picture I am just running the front straight at Texas World Speedway and they isn't much side loading until you turn into either turn 1 or 15 depending on the direction we are running.

I have down the wheel and tire test swap street and track, same effect. It is more a drift than a hard pull, the faster I go the more input I have to give to keep the car straight.

LehmanZ06,

I did ask for the before and after alignment, but they didn't save the original before with this last alignment. I have the three subsequent sheets, but all if these were after the cat was lowered and alignment done. I take a picture and attach it to the next post. The car is going to a race oriented shop for complete strut check and setup this week.

Ur20v,

I will have the race shop check it this week.

Texas RS

Alignment 1 post lowering.

Texas RS

Alignment 2

Texas RS

Final alignment...

LehmanZ06

Caster is messed up.
Did you check that strut tops were in the same holes in the plate on top ?

Also did you look at the front lower control arms where the shims are located to make sure they were the same size and amount on each side ?

LehmanZ06

Could you also post for in degrees and not mm