Guys, so the winter really beat the crap out of my car. i have 4 wheel bearings on their way, as well as upper strut mounts for the front (the front end feels totally disconnected over bumps).

i can get my hands on gt3 cup car LCA's for cheap. but before i do that i wanted everyones input.

what is the benefit of gt3 LCA's ? I believe i need to get tarret spacers and bolts for the front diff right ?

besides being able to have more negative camber up front, what other advantages would i get from LCAs's ? Does it actually widen the track ? Is the ride going to be stiffer ?


lastly, if i put the gt3 lca's on, what alignment specs do you guys suggest ?
The most important thing for me in terms of grip and handling are medium speed turns (40-60mph).

how would i set up my sway bars ?

i am running on toyo r888's for this entire season. since i (more than likely) wont be doing bigger turbos yet, i might as well enjoy the handling of the car.


pwrhound i hope youre reading this and preparing a long detailed reply

 

Steve,

I don't have the LCA, but no one is answering so here we go, all IMHO of course and anyone pls correct as needed: The primary goal of the LCA is to increase front negative camber beyond the max minus 1.2 of stock. I do not believe it widens the track, not to a degree that matters anyway, but I would call Ira/Tarett to make sure. I don't believe it makes the ride stiffer, if you stay with the stock thrust arm bushing and you don't change to the monoball end http://www.tarett.com/items/996-997-...-arms/list.htm , but perhaps those of us with the actual LCA could chime in and correct me as needed.

Because front negative camber of minus 1.2 is fairly aggressive for street driving already, LCA & more negative camber are perhaps more appropriate for track junkies who drive very, very high cornering speed. If the most important thing for you is grip and handling at medium speed turns, 40-60 mph, IMHO you don't necessarily want camber more than 1.2 (too much camber is harmful also: decreases straightline traction, speed, and braking, increases tire wear), hence you don't necessarily need the LCA.

The sway bar settings would vary depending on which bars you use, your taste, and what other suspension components are on your car. This is a truly empirical trial where you are judging comfort against body lean (for people like me, mostly street driving), against understeer/oversteer behavior (this last one for advanced, high speed, drivers).
That said, because a 4 wheel drive car inherently understeers, and Porsche further dials in understeer in our Turbo for safety, the general idea of after market sway bar setting is to counter this, meaning you would set the front bar relatively softer than the rear bar, hence increasing oversteer to counter the factory understeer. In my car with Bilstein and GMG sway bars, the setting is soft front, medium rear. Hard rear in my car is nearly un-useable because ride becomes extremely uncomfortably stiff. This is what I meant when I say the "correct" setting depend on what else is in your car: in another car without Bilstein, hard rear may just be fine.

The first page of the Bilstein thread in my signature has an alignement suggestion for street driving - a tried and true setting that a number of people have used. Camber -1.2 front/1.8 rear; I would suggest this as a start. My tuner also added very slight toe out in front to counter the somewhat lackluster steering response of our 997 Turbo's; I love it and very highly recommend it (you could see it in the diagram). Hope this helps.

 

Steve,
For a pure street car I'd stick with the stock GT3 LCA as they have rubber in the end joints as opposed to monoball like the Cup arms and as a result will be a bit smoother. Additionaly, the Cup LCAs are generally longer than the regular TT arms and may give you too much camber to start. I'd stick with the regular GT3 arms in your case. I have the GT3 arms with the Cup monoball ends and just the Cup ends are 3mm longer per side. Contrary to the post above, one of the bigger benefits with the GT3 arms (besides being able to dial in more camber) is the fact that you will widen your front track which will help with turn in and front grip. On my car for example, to maximize track, I have minimum camber set up top on the strut towers and I am running 11mm of shims per side on the GT3 arms along with the 3mm longer monobal ends. This effectively widens my track by a total of 28mm (1.1") over stock. I am running -3.25º camber in the front however. One thing to keep in mind is that as you add shims to your LCAs, you are also adding caster as the whole wheel assembly is pulled forward. Add enough shims and your tire will interfere with your front fender liner. As a result, you will need to use the front offset hole on the GT3 thrust arm bushing or better yet add adjustable solid caster pucks like Tarett sells. These are a great addition and will not add any NVH. The Cup arms come standard with these. Since you are AWD, you will need to be careful with how many shims you add because you are limited with the length of the front drive shafts. Alignment wise, everything is a trade off. For aggressive street I'd shoot for max of -2.0º camber front and -1.7º or so rear. Depending on how low your suspension is, you may be able to get -1.5 in the front with stock components. Your tire wear will still be good. Toe in front at +0.06' (minutes) total and in the rear +0.30' total. For medium 40-60mph turns you don't need anything too aggressive, stock should be fine. As far as sways go, again at 40-60mph you won't see any earth shattering differences. I'd start with them set in the middle and adjust from there. Your AWD will induce some additional understeer and your driving style will determine your sway settings. I have my set up geared toward understeer (via a square spring rate set up) which allows me to enter a corner fast while trail braking very hard with out having to worry about the back end coming around unexpectedly. I am set in the middle on my front GT3 bar and one hole from full soft in the rear on the GT3 bar by my set up is not representative of a normal Turbo.

My set up is geared more towards track as I am at -3.25ºF/-2.42ºR camber and +0.04'F/+0.30'R toe. My car is RWD. Weight is 3259lbs with fuel minus driver. Everything is monoball on my car with 1100F/1200R spring rates. That may seem hight but surprisingly, when my JRZ Pros are set on soft compression, my car rides better than a stock 997TT with PASM. That was a comment a friend of mine who owns a 997TT made. He rode with me a couple of weeks ago and could not believe what a difference quality shocks make. Hope this helps..

 

I use the street gt3 LCAs with shims up to -1.5-2.0 up front, no worse ride. Direct bolt on, need the litronic bracket. Tarret sells them, give Ira a call.

 

thanks for the input guys !!!
great posts, lots of info to digest.
btw i have gmg springs (lowers the car an inch), with gmg sways.

btw, would i need to change alignment and sway settings for slightly faster corners (60-80mph) ?


i was going to install the arms this saturday, so i dont have time to get litronic brackets. can i reuse the brackets on my oem control arms ?

 

I don't think you can reuse the bracket.
With the springs and Lcas you can get -2.0 neg camber, any more and you have to use the spacers or go from above.

 

I may be that guy that rode with you. Maybe? All true though.



I cant believe how well you car handles and rides. You have to be joking that your car couldn't be driven every day. In fact, I would take your suspension setup over mine with or without the PASM on.

Next time, lets put the suspension on its max stiffness!


I guess I will see how crappy my car handles at the track with the stock 19's on it. (PASM on of course so, I feel better.)

 

Turbos are broken in. That was a looong 1000 miles. Let's catch up this weekend. I'm around.

 

Thanks for the very good explanation. Some questions please:

1. Outside of the monoball, GT3 LCA and Cup LCA are identical in length/structure/function, and *both* are longer than the 997 Turbo's stock LCA?

2. Do I understand this correctly about how they work - to increase camber, "after-market" LCA's have to be longer by definition because that's how they work - "pushing" the lower part of the wheel out and hence tilt the upper part inward?

3. Is the hub of the wheel pushed outward also with LCA's? If not, the track is widened only in the sense that the wheel is tilted, no?
Thanks.