What maximum negative camber will be achievable using GT3 upper strut caps alone on C2 car with same stock LCAs in place with PSS9/10 coilovers? Is -2.5 achievable?

What would be best place to buy those caps from? Quick search did not show anything or may be I did not look for correct part name.

 

To do what you want I believe the best way is with GT3 LOWER control arms. That is what many of us with 997 cars do for more camber. Plus you widen the track a little too.

With GT3 Cup lowers you can get -2.5 camber no problem.

This is what I have and I run -2 camber front and -1.8 camber rear.

 

Yes, but LCA way is more expensive plus with caps you have additional half inch of clearance an the wheels` top so one can run 9" or even 10" rims in front, well, according to rennlist post.

So I generally wanted to get some sort of confirmation on this info. GT3 997 LCAs are $1200 for parts alone plus for xenon lights something else has to be changed there IMHO, where its sensors get mounted, I thought that upper caps side of thing may be easier to do as it has to unmounted anyway during coilovers install.

 

One more question, just want to know your opinion - considering stock 18" rims and toyo r888 which tires sizes are best for rear 10" -
265/35ZR18 97Y RD
275/35ZR18 99Y RD
285/30ZR18 97Y RD
?

Some say wider in rear is best, other say that closer to square is better to limit understeer.

Front options they have are 235/40ZR18 91Y and 245/40ZR18 93Y but both have 8.5" as recommended rim and stock 18" rims are 8" only.

My gut feeling says 245/275 combo, right?

 

As Mike said, the best solution is lower control arms, which you can get very reasonably at Suncoast or Tarett. I run -2.3 / -2 camber. For R888 you want 245/305 on 8.5" front rims and 11" rears. 275s are way too narrow and don't have the correct diameter. Stock wheels at 8/10 are not optimal for track use. Right now you can get a set of 245/305 RA-1s from Frisby Race Tire for an amazing price (close-out). I just picked up 2 sets.

 

I see. It seems to be common opinion about 8/10 18" rims. But I still hate an idea to buy 3rd set of rims, just from storage perspective it is a PITA. Well, thanks for an honest opinion nevertheless. I`ll think about it all.

 

People used to shoe-horn 235/295 Cups on stock 8/10" rims. I tried a set and it really wasn't optimal. The tires wouldn't even stand up on their own because they were too narrow. I got a set of Volks at Tire Rack on close-out and they also have the new OZs that are reasonable. Or, just use a set of your 19s and run the R888 in 245/305. I did that for a while on 19" Volks and they were fine, though loud.

Just checked Tire Rack and 18" Volks are $599 each, which is a great price for light, strong, forged wheels. If you prefer silver and are interested in running 18" RA1s, let me know and maybe we could swap (I have new-this-summer 18" Silver Volks and would be just as happy with the gray ones).

 

Well, new set of rims pushes that entire project even further south as to go with r-comps pushes me out of stock class so it makes sense to do that only if I redo suspension as well including LCAs - so it seems it all will cost a little fortune altogether.

19" OZs I have now are botticellis and they are 3.5lb heavier than ultraleggeras or volks at 25/27lbs - not overly critical issue but, still, not quite optimal. I love em for street and their looks (even if it`s not a commonly shared opinion) but for racing somewhat like 18" allegeritas would probably be better at 17/20lbs. Not sure. I'll have to think about it all.

 

The Volks are 18/20 lbs forged at $599 each, which is going to run you about $800 more for the set of 4 than the 18" OZs (which are hard to beat for price). I'm totally unaware of the racing rules, so don't go by me. I just have a sense the stock 18s aren't optimal and the OZs and Volks are great wheels at reasonable prices. Honestly, I'd post over at RennList in the Racing / DE section to get more guys in your situation that have gone through all of this deliberating.

 

I have the Volk TE37's as well, very good wheels, decrease the unsprung weight of the car, and very durable wheels. I run 8.5 x 18 and 11 x 18 and run 245/30 and 315/30 Hoosier R6's without any rub issues.

Ron I think that Utkinpol is worried about the Autocross rules. If you want to run a 10" wheel, I did manage to get a 295 on them and they worked fine, but I wouldn't go any wider. I do have a set of 285/30/18's Yokohama 048's that have only a few street miles on them that I will sell for a good price, you can pick up some fronts from tirerack and mount them up.

 

I run 9x18 front on a lower suspension with GT3 lower arms with mo problem. 9x12 front 12x18 rear is what I use

 

i think C2S has a bit wider upper section in front wheel area than C2. Not sure if 9" rim will fit into mine, would be nice to try it if I would have it somewhere...

Again, it all gets more complicated than I originally wanted to do. Original plan was very simple - just to swap out upper caps (which should be relatively easy and doable DIY job) and get a bit better camber in front. Then drive it like this and later decide if I do want to put in coilovers or not sometime mid season.

Going down LCA path I will need completely dismount struts that makes no practical sense to put them back, so, price goes up right away.

Interesting thing that no one seems to know about those upper GT3 mounts, I will need to visit my local shops it seems to discuss this. Too bad.

I see vividracing has something like this:
http://www.vividracing.com/catalog/m...0-p-52995.html

and they claim to provide additional degree of camber in those caps. Not sure if it is the same design as in GT3 caps. Can anybody elaborate?

 

That looks like an interesting product. As I read it, you can gain up to an additional degree of negative camber. So the stock suspension is good for maybe -0.8 degrees, so this could get you to -1.8? For street / track purposes, -2.3 degrees has been what I found to be optimal. Racers would put in -3 degrees or more.

Also, it says they are for the C2, so I wonder if that means the base car suspension and not the PASM? Might be just fine for your C2, but might not have been an option for my cars that had/have PASM.

My Sport PASM car is good for about -1.1 degree on its own, so if this was an option for me and I could have gotten to -2.1, then I would have called it a day for much less to change this part than to do the control arms. What does Vivid say?