daylorb

I picked up a set of GT3 lower control arms for my '12 Spyder. Done a few track days and can definitely understand the value - outside edge of tires is wearing pretty quickly, particularly after COTA.

From what I understand, the shim size needed is different for every car depending on ride height. Right now mine is a bone stock 987.2. I'm guessing someone has been done this road before - any thoughts on the right shim size to buy in order to enable alignment at -2.5 degrees?

PorscheAddict

I would do 13-15mm per side. That was enough to get me to -2.5 on my 981CS with stock suspension with a little room to spare on the upper camber bolts in the strut tower. You could always go 16-20mm and adjust from top just to be safe, since the top allows over a degree of adjustment. FWIW I'm bumping to -3.0 for next year.

daylorb

Thanks - that is helpful. I think the ride height on the Spyder might be slightly lower than a CS so the 13-15 should be create more I believe?

PorscheAddict

Lower is more for sure, but I don't know whether 987 suspension is different or not. I think 15mm would at least get you close enough to be happy, whether that's 2.3 or 2.7.

lovetoturn

I have 12+1=13 with the litronic bracket, which is plenty to get -2.7 camber at this time and have room to spare. Keep in mind that the more shim you add, the more you will continue to offset the caster and lower the car. At 13 mm of total shim, my car (981) is about 6mm lower in the front. The caster is right at the limit on one side and slightly over on the other. With measuring the suspension triangles and a bit of geometry, it looks like a 10 mm shim with the 1mm litronic bracket will yield the perfect caster, enough room for almost -3.0 camber, and 5 mm of lowering in the front of the car. This is of course on a 981, which I believe is very similar or almost identical to the 987.

PorscheAddict

More caster is better unless/until your tire contacts the front fender liner or you get bump steer issues. On stock suspension 981CS with 13-15mm shims and RSS thrust pucks I'm sitting at 9.5 caster per side, a full degree more than "the limit." The car handles much better for it, since caster increases dynamic camber mid-corner, which is of course when you need it. It also makes the steering heavier (good) and makes the car tend to return to center more easily after corner (good). I don't have any other issues other than increased tendency to scrub the front tires in parking lots, which it already did stock anyway. 9.5 caster is enough to rub very slightly, but it wore away a couple mm of liner and doesn't rub now. YMMV.

daylorb

Thanks - this is super helpful. I wish I had more of an idea of what I should change but I'm a newbie to doing any regular track days. Overall I thought the car did pretty well but I probably don't know. The one thing was clear - the outside of both front tires was getting it worse than anywhere else so I figured that would be step 1. Sounds like the 10mm would be the right first step.

As a package deal I got a tarret rear sway bar and drop links - although I have no plans to use them given everything else seemed to work pretty well.

zedcat

I have a 12 Cayman R, so same suspension as your Spyder. I have GT3 LCAs with 10mm shims per side for about -2.3 deg camber. I was able to get -1 deg before the GT3 LCAs. So about 10mm shims for -1 deg is a rough rule of thumb. Also added Tarret rear toe arms as recommended by my mechanic at the time. This was more to simplify adjustment. I have about -2 deg in the rear.

I ran 200 TW tires for awhile, Yoko AD08R, Hankook RS3, and later got 18in wheels and Nitto NT01s.

My 2c worth would be do the GT3 LCAs which will improve tire wear and leave all else alone for awhile. Bridgestone RE71R is arguably the best DE tire currently. Not sure if the 19in sizes are currently available though. Also consider getting in car coaching. Most drivers would get more out of coaching than car mods.

PorscheAddict

^ Solid advice from Zed.

One more thing I'll add is that really excessive tire wear can be mitigated by tire pressure. I don't know what pressure you're running, but you should consider going higher in front to keep your tires from getting toasted if that's necessary, maybe 41-42 PSI hot or so. I would love to run mid 30's hot, but driven hard these cars still eat the edges somewhat at -2.5 camber. Yes, high pressure will be slicker and get greasy, but at least your tires won't die in 1-2 days of DE.

daylorb

Thanks - more great advice - and that makes sense on the shims. So 15mm at -2.5 give or take. Did you put LCA's in the rear as well? Doing some searching I thought I could get 1 to 1.4 on the rear with stock, and do -2.5/-1.4.

My plan is to get a different set of wheels for track, not because I'm such a great driver, but so I'm not eating through road tires. Which 18 wheels did you get?

I just switched from RE71's to PS4's. I've always had PS2's on my cars since 2011. The RE71's were fine, but at end of life so I went with what I know.

Tire pressure - it was really cold last weekend. I've been starting with 29/30 cold, getting 38+ on the pyrometer in the summer, but I forgot it last weekend. It was 46 degrees out, so I doubt they got that hot. I had not considered going higher, but makes sense now that I think about it. I think I've had more oversteer than under, so a little higher pressure might help. It's all new to me at this level.

The coaching is happening - at COTA I'm not solo certified, so have a coach in the car and it is worth it's weight in gold. It is only $100/day to have someone ride with you - where can you get that kind of bargain? At the other track, I'm lucky enough to get coaching from the Dollahites - whether it is the all day sessions they do, or even on practice laps they have hopped in and coach for a couple laps. Can't say enough about what great guys they are - father and son Bill and Scott. Scott won the Pirelli World Challenge GTS division at COTA this year - knows his stuff.

PorscheAddict

I run -1.8 rear with stock suspension on 981CS. I'd like to go up to -2.2 or so once I go up in front to -3.0, but don't feel like dropping the coin on rear LCA's when I have other priorities (center radiator, track wheels). I may snag some Apex once they release them - until then I'm on stock 20's.

zedcat

On the Cayman R I did not go to GT3 LCAs on the rear, only the Tarret toe arms. I was under the impression that about neg 2 was possible in the rear with stock parts. Not sure though as I added the toe arms when I did the LCAs in front. You might consider having the front and rear camber closer. I am at neg 2.3 front and neg 2 rear. I had a pro coach drive the car to set a reference data lap (AIM solo) and he felt the car tended to oversteer at the limit. We dropped rear tire pressure a little after that. Depends a bit on personal preference.

My 18in wheels are OZ Alleggerita from tire rack. They are cast not forged but still pretty robust. Much cheaper than replacement 19in Spyder wheels.

Just about every tire I've tried seems best at about 32 to 34 psi hot. I'll usually start first session about 28 cold and then bleed at the end of the session to get to that range. Lots of factors in tire pressure preference though.

Not to go off topic but presume you are running a high temp brake fluid at COTA. I use Castrol SRF. I'm running PFC 11 pads and have used Pagids also. I have the GT3 ducts in the front. COTA can be brutal on brakes. I had some cooling issues trying to run in July, Aug and had the center rad installed which cured the problem. Had to get a portable coolshirt for me too!

daylorb

Thank's, I will look into those wheels. I have put ATE 200 in for fluid, using stock R/Spyder pads (new set) for now. My thought was start with stock, see how it goes, and work out from there. Clearly noticeable were the outsides of the tires. From what I was able to find in the forums, the stock R/Spyder pads are pretty decent. I suspect at some point if I progress I'd need something a bit more industrial strength.

I didn't have any issues with the brakes at all, although I don't think I'm pushing it very hard and quite frankly I had to brake soft and early most of the time. I only got a couple of clean laps so even on the straights I was often on someone's bumper having to slow down way early.

On the 2 clean laps I got, my times were both 2:49, my brake in at T1 wasn't bad - tried to hit it at 150 mark. On T11 it was earlier, although not pathetic, but T12 I was doing it way, way too early - hit 132, but chickened out and started braking around 300' and barely needed more than highway pressure.