I remember seeing a post on alignment specs away back, probably almost 2 years ago, and I can't find that post. Can someone help me regarding a good autocross alignment spec. My thoughts are 2.5 neg front camber, 6.25 pos. Caster, total .28 degrees (.14 each side) toe out and 2 degrees neg rear with a total .14 degrees (.07 each side) toe in.

I will be running wheels with the stock specs 20X8 ET 57 front and 20X9.5 ET45 rear with Forgeline Wheels on the Yoks 245-35-20 front & 285-35-20 rear on a 2015 Cayman GTS manual tranny with X73 and PTV.

I would appreciate any info.

Thanks

 

Do you have coilovers and/or other non stock parts? If you do, spring rates and sway bar specs matter a lot.

 

Also, I'm not sure how you're going to get 2.5 degrees camber on the front without aftermarket parts.

 

No go-fast stuff. All factory stuff.

 

What about the rear camber? What would be the max I can get in the rear?

 

So typically this is what I tell local PCA autoxers for a starting point for alignment:

Front maximum negative camber possible matching to lesser side.
0 front toe

Rear 1/8" toe in
Max camber to match lesser side while retaining that toe setting above

In a car like yours I'm guessing it would look like this:

-1.5 front camber, 0 toe
-2.0 rear camber, 1/8" total toe in

 

Thanks, I appreciate the response back.

 

I also prefer 0 front toe on a car that does any street driving. Stock cayman is going to wear the outer edges on Yokes pretty hard. If you are not a top of the podium guy I would recommend trying the Falkens. We just did a test and tune with my partner's 981 cayman S this past weekend. The car seems pretty happy on the Falkens, and we haven't even done the alignment on the car yet. I've driven a cayman on yokes and it didn't do anything for me. I'm a top 25% pax guy at national events, and all the yoks did for me was cost more money and last fewer runs.

 

Thanks for the info. At this point, I haven't decided to run the 20" wheels or the 19" wheels. I'm kinda leaning on the 20's but, my concern is if Yokohama decided to play in another Arena and no longer support Autocrossing that would be a concern if I stay with the 20s. All tire manufacturers play that game and they have been doing that since the 80s. If that occurs, I guess I could try the new Continentals or go to the Michelin Pilot Sport Cup 2R tires and run in SSR but, I could also run the Hoosiers in SSR but, with the lack of camber, I would only get about 30 runs or so before the outside edge cords.

So far, I have been very happy with the wear pattern on Yoks with my Corvette Grand Sport with only 2.25 front neg and 1.6 rear neg. The Arizona summer weather will be interesting on the Yoks, I'll just have to bring lots of water to spray.

The Las Vegas National Tour will be my first warm event on the Yoks with my Grand Sport. My Porsche probably won't be setup by that time but, I'm hoping but, I doubt it because it'll be awhile before I get my Forgelines.

I'm hoping to have the car ready for the South Texas Texas Tour in May. The Peru Tour in June shouldn't be a problem and if it is, I'll run my Grand Sport in the meantime.

At least both cars will be in the same class. It appears that I will have to run in the Production Category to be legal with the Porsche PCRs because of the tire sizes and the wheels will bump me up from Showroom Stock

The Falkens do not produce any 20's at this time and that may be a point for me to make my mind up and run with the 19s for future choices.

 

981 GTS with X73 alignment sheet. Only change made to this over 4 years was hair toe out in front. You may not like Falkens the first time out on them. Second time they will be great. BTW, 19 inch wheels/tires are cheaper than 20 inch and help acceleration (gearing) and cornering (lower CG).

 

I would be interested to know what you think of the Cayman VS the corvette. I know yours is a grand sport, but to me the c6 z should still be a super street car, if we were really classing to potential rather than trying to give a specific car a place to win. Jacob Glover (second at nats last year) was at the test and tune this weekend and was consistently .5 to .8 quicker than us on a 30 second course. I would like to better understand if the 981 S should really be able to compete with that car. We didn't buy the car to be competitive, we bought it because we liked the whole package.

 

I always wanted to know how my Cayman GTS would do especially with the PTV. I bought it with autocrossing mind but, in the last few years I've been busy with my Go-Fast C4 Corvette CAM car and my C6 Grand Sport Grocery Getter and trying to keep the car stock and the lack of availability of a quality autocross shock for the rear of the 981, I essentially just used the car for PCA Driving Tours and Social events. Thats why I only have 11K miles on it. I decided that I can't get a good shock like a JRI or a Penske for the 981 and keep it stock and legal for PCA and SCCA, and not cut holes in the body, etc. So, I decided that I'll just get the wheels and tires, and alignment and play with it just for giggles.

 

This. Without GT3 LCA or a camber plates, the most you see up front is -1.5 and not likely-2.0 in the rear.

 

Coincidently I am in the process of prepping my '15 981 GTS for SCCA AS class. I have only had it out once at a local event on street tires with a factory alignment and although I had a blast driving it, the car needs the basics to be competitive. Thought I would start with sticky tires and a competition alignment. The alignment is pretty straight forward and looks like I need to add some camber over the factory stock alignment. For tires I would like to start with keeping the stock 20" wheels and run a set of Yoko 245/35 front and 285/35 rear. I was hoping to avoid buying new 19" wheels right away as I will be on a bit of a learning curve for sure. However I am finding 245/35's impossible to find and was told they are not on Yokohamas production schedule for at least 90 days. Wondering if anyone has heard of trying the 245/30's on the front as an alternative?

 

Does anyone know if I need to run TPMS sensors in my new Forgeline wheels so the car's electronics don't play havoc when I am autocrossing? I don't care about the Air pressures being displayed on the dash. This is for my 2015 Cayman GTS with the manual tranny, PTV, and X73 Sport Suspension. Any info would be appreciated.