997gt3north

It is categorically not from the caster from a shim only alignment

I run -2.7 and have no issues having not rotated the struts

Could rotating plus shims makes the caster better - likely - but that isn't what is being described here

Either the alignment is grossly off or there is a mechanical issue somewhere that is going to have to be found as it was said earlier that the car was fine before

Also in terms of toe out at the front with the gt3 I just do not have any issue with it on the street or the track unlike in other cars as I suspect that the very light front end versus front engine cars really reduces the tramlining that I agree can be really suck - my s4 track car cannot be run on the street at all with toe-out - the gt3 has no issues with 1/8th total toe out

Good luck finding the problem

Paul

todinlaw

I run 0 toe but I know others run positive toe in the front. I am just wondering if the alignment did not slip or if the machine had a brain fart and gave bad readings. I know I did my alignment like 3 times last year and saw changes admittedly due to OE rear toe links, which I am changing this winter. but like all hear have said when you change one thing it affects all the others. If you go back and put it back on the alignment rack and its spot on, then if you find no other explanations I would start with Toe settings as camber should only make it better, you might look at the ratio of rear camber to front camber I like to keep that at about -1/2 a degree less in the rear.

On my earlier caster comment. I was told Caster is not adjustable on this car that is not to say that caster will not move with adjustments but it is not adjustable per se. Good luck, you will find it because the history is this car can get hooked up, you just need to find whats missing.

va122

Castor is adjustable on this car, there are the three holes described earlier that you can use to adjust castor. I started with the 8 that came stock and increased it to 9 but didn't like rubbing i got, so i backed off to 8.5. If you really want to you can get like 11deg but you have to push the coolers and stuff forward this is done on the cups in WC.

I do have to say at this point my suspension is all cup and RSR parts so I may be getting confused

996FLT6

va122- may I ask what suspension bits u have done? I'm running stick but with Trg rear toe links. Thanks. Mike

Bob Rouleau

340 - If you get negative camber using only shims you will have way to much caster - I had 9.2 degrees in fact and tires would rub. Too much caster makes the steering heavy.

If you rotate the struts to get negative camber, you end up with too little caster. Rotating the strut should give you about neg 2 with shock all the way towards minimum camber (slot at the top of the strut mount). Then use shims in the lower A arm to get what the negative camber you want. You should end up with the caster between 8 and 8.5 degrees. 8 degrees is spec for the car. Done right, it does not handle like a truck

Bob Rouleau

Paul - I'd be cautious. Did you do the work yourself? If not it is possible that a good shop like Fiorano would rotate the strut and then use the alternate hole in the A arm to increase the caster to its nominal level. I assure you that just shims to get neg 2.5 or more will cause a significant and undesirable increase in caster.

Best,

Greygt3

Exactly what Bob said. You can't just shim ( if you want more than 2 degrees) and keep the caster in spec.

340Elise

Guys,

Thank you so much for all the feedback. I will be printing out this info and taking it to the dealer tomorrow morning. I was working with the mechanics on my car and I am afraid that we were paying so much attention to the camber, that something else got out of wack. On top of that, I saw the alignment printout in the printer and forgot to grab it. However, the head mechanic tells me that the info should be saved and that we can look it up.

I will get the current settings and the changes that we make and post the results here.

Drqiman's description of how my car behaves is spot on; he put it better than I did.

My tires are at least half worn and I have never had issues with them. I personally like the plus 2 sizing in the front and plus 1 in the rear.

I did have the car lowered about .25 inch, but that was before this last alignment and it was fine (other than a bit more front spoiler scraping).

All of the camber was achieved with the shims and by pushing the top of the struts all the way to the inside. I'm still a bit confused on the rotating of the struts to achieve camber; I guess I need to look at them to understand how this works. A picture or a puppet show would be helpful...

I did do the steering wheel at the same time the alignment was done, but that cannot be the problem. I am convinced it is the alignment and hope to get it sorted out today.

It is blowing pretty hard outside, I hope I don't wake up to snow!

Thanks again!

997gt3north

Bob,

- The car started its journey at a dealership in NJ two years ago this day - that is when I learned that -1.8 was the max you could get (even though I told them to put the "track" alignment on the car)
- this dealership didn't exactly prep track cars (NY city crowd)
- eventually parts guy looked at the 996gt3 parts list and found the "shims" - they weren't 997gt3 parts at least at that moment
- we ordered them and we got to the "track" setup of -2,-2.5 (f/r) and that is how the journey began
- car was much better than stock but after about 10 days on the car the "pushing" was really obvious
- shop in NJ (Stable Energies) seller importer of the "Safety Devices" cage then got the carinstalled the cage, seats and increased the front camber with a few more shims to about -2.3
- then moved to Toronto
- many more trackdays, more feedback from rennlist, few sets of tires and brake pads later, GTek in Toronto now preps the car
- Jack at GTek did the R&P and the Guard LSD and I kept going back to him telling him how the car was handling and we ended up at -2.7f, -2.3r with 1/8th toe-out in front with the GT2 rear bar in the middle
- switched tires to the 235,305 /19s R888s (the front tire is very square)
- as I have gotten faster with the car, turn 5B at Mosport is th only corner if i run in soft mode where the front left wheel will rub for a tiny fraction of a second (car is not lowered)
- i like the steering feel so no need to change in my opinion

- my guess is that when i change to better tires next season (R6s) the higher loads generated may require the strut rotation to avoid more rubbing
- so far the tracks that i have run on with this setup (VIR, Mosport, WG) rubbing has not been an issue

Paul

va122

FLT6,

I have Cup rear shock mounts, control arms, drop links, erp upper "dog bones", adjustable toe links, monoball everything, Moton Motorsport tripples the list goes on and on.

Slippery slope

Bob Rouleau

Paul, thanks for the input. I've added it the the "store of knowledge". I know that our cars can vary quite a bit from one to the other (to my surprise I might add).

My experience with a pair of 996 GT3's and a pair of 997 RS, (my wife and I have the same cars except for color, she is a senior instructor too) was that shims along increase the caster to the point where full lock causes rubbing. Another local wore out his fender liner - made holes in the left one at Tremblant.

The ideal way to get lots of negative camber is to rotate the strut which gets your about neg 2 with the top shock mount in the minimum camber position. If you measure caster it will be too low, in the high 6's low W's. Then add shims in the lower A arm to get the desired neg camber and caster in the 8 to 8.5 degree range.

There is an alternate method, after rotating the struts, in the lower A arm (do a search on this forum on camber/caster and you'll see pictures back in 2004 I think) there is an alternate hole which increases caster. In that case, you then slide the top of the strut mount to the inside to pick up the additional negative camber and benefit from the added caster derived from relocating the arm. Shims may or may not be needed, I didn't do this one myself.

BTW, I assume you saw the notice from Toyo who now recommend hot pressures of 32-35 lbs on the R888 and suggest less negative camber. I corded the inside edge of my rears with neg 2.5 in front and neg 2.4 in back.

Lastly, I sent you a PM a while back. Do you know Peter Bromby?

Best,

naparsei

Take it to Chet's. They align most of the race cars in the area.

TraqGear

Stephen,
I had my dealer do the standard track alignment in the manual last year and haven't moved it since. Works like a champ without affecting my street tire wear much at all, if any. I think less is more sometimes with these machines.