TAI2

Now that I have 2005 Carrera S (after I trashed my 964 at the Glen) I am starting down the slipperly slope. I have seats, roll bar, 18" wheels and semi-solid engine mounts taken care of and I am now focusing on suspension. I have read a lot about GT3 lower control arms which allow for more camber adjustment and think I have the scoop. I have read a bunch of posts and I am looking at the following so please let me know your thoughts and if I have it wrong or missed something.

A. 996 GT3 LCA's (are much less expensive than 997 versions) and have rubber bushings.
B. 997 GT3 LCA's are of a "higher" quality but basically no different than the 996's (other than price) and have rubber bushings.
C. 996 GT3 Cup LCA's are slightly longer, allow for greater camber adjustment, have rubber bushings and you need to change to 996 trailing arms to allow for a better/easier caster adjustment.
D. Tarett LCA's are equiv. to the 996 GT3 LCA's but come with a kit that makes it easier to make caster adjustments by providing a spacer kit (therefore no need for new trailing arms) and have rubber bushings.
E. RSS LCA's seem to be very high quality, look sexy but generally are equiv. to the 996 GT3 LCA's but come with solid bushings. I considered these but feel I will opt for the rubber bushings as I am trying to build a DE/Street car and feel the soild bushings may be too "hard".

All the above need a Litronics kit for proper headlight leveling.

In the end, I am likely to buy the Taretts as the price is good, includes the spacer kit so I do not need to change the trailing arms and also include the litronics arm/shim.

What do you guys think? Thanks,
Tom

mooty

996 vs 997 LCA are the same, just webbing in the arm is different. no way in hell you can tell the difference in driving. get cheaper one.

996 cup isn't longer, it's split and have shims to increase camber. you dont always need trailing arm (thrust arm) to do caster, you can also change the puck on the LCA.

when you say rubber in LCA. you need to be more specific. the inboard side has rubber bushing but can be replaced with monoball. also the thrust arm puck on the LCA is also rubber, which also may be changed to monoball.

i would get the tarett stuff. i have everything they got on my race car.
for dual purpose, i see no reason to go full monoball.
i would talk to ira at tarett, he gives no BS. and knows his stuff.
if i were buying, i do split LCA up front, that way you can get all the camber you need. you dont need the thrust arm puck, too hard core. inboard LCA bushing can be changed to monoball but not cheap. and imo not needed for dual purpose car. (but unlike most ppl, i like the softest sprung car i can get away with. so take that advice with grain of salt).

you dont need rear LCA. you can get up to 2.5 deg of camber with stock arms.

i dont know how toe are adjusted on your car. on gt3's we all need adj toe arms.

upper control arm (rear only) aka dog bones are not needed for dual purpose car imho.

1. just call up tarett. he is very good and will explain all you need to know
2. find a very good race shop and do not take it to dealer. if the tech does'nt understand what to do once he sees the parts, you are in the wrong shop.

mdrums

Tom, listen to Mooty...he knows!

I have 996GT3 LCA's with some other Tarret parts. Only reason I got 996 GT3 LCA's was because a friend of mine was getting some parts from PCNA and hooked me up with a deal.

Tarret is great....also check out what RSS has too.

TAI2

Thanks guys. This is great feedback and has really helped.

utkinpol

I think for LCAs best choice is a set of 996 GT3 LCAs, for both front and back axles.

Tarrett and RSS options are not much worse but it is just my approach to use OEM parts only for any critical components.

Also if you will proceed with that - I am not sure if it is overly critical to replace bushings in LCA ends to solid steel monoballs as GT3 LCAs have different rubber and it does not really compress that much. for track only car it is probably worth doing, for dual purpose car - not. but you need to replace inner bushings that are used for fork arms connections to solid metal ones.

keep in mind, those LCA ends do cost $250 a piece and at that moment RSS option starts to look very price attractive.

what is more subtle to dynamic camber changes is shocks upper mounts - you do really want to get rid of stock upper mounts and put on GT3 monoball ones - they are very well protected from elements and it is worth extra price.

same as mooty said - tarett is a choice for rear toe arms and overall it is a good stuff, but ERP arms and monoballs are better. do some research and be very picky about from whom you buy this stuff as cheap monoballs may go really fast. RSS, Tarrett, ERP are pretty much only choices here, and I would use OEM for everything what works.

TAI2

Thanks for the very helpful info.

mooty

a lot of the stuff from tarret are ERP parts.

tarett LCA is oem part on the arm, they just change the inner little piece to monoball.

utkinpol

i suspected something like that as rod ends on tarett rear toe links were practically identical to all rod ends on ERP dogbones and fork arms.
good to know.

TAI2

Great stuff. Thanks.

jurnes

Buy your LCA shims from Tarrett also. About 1/2 the price of OEM shims. Not an insignificant amount when a 10mm shim cost $40.00 from Porsche/Suncoast!

TAI2

Thanks for the money saving tip.

TAI2

Hi Gang,

Thank you very much for the suspension advice. I am very familiar with 993 and 964 suspension and track car mods and I am just learning about the 997 so your feedback is very much appretiated.

I was wondering about rear LCA and/or other suspension changes. In talking about my upcoming project (2005 997 S) I have started to get feedback that I should also upgrade the rear suspension to improve stability. Most of the time people talk about the front suspension to improve camber adjustment and to provide a slightly wider track. Now I am hearing more about the rear but mainly in regard to stability. What are your thoughts? Thanks again.

Tom

utkinpol

suspension re-haul is really only limited by your imagination.

you really have to decide what is it you are building - a track car, dual purpose car, street car with very occasional DEs... that will dictate list of required changes.

very good starting point to see how suspension can be set - look at 'spec 996' specifications.
http://www.996specracing.com/The_Spec.html

it is actually quite a well weighted solution - not an overkill like 4 way adjustable ohlins, etc. but note that 996 JRZ package will not fit 997 but they have similar JRZ RS package for 997.

So you need to decide first if you have trailer for tires or you going to drive to a track on your own car. In trailer case that means you can use hoosiers or racing slicks. that will want more camber, stiffer springs.

riding to track will put you in same game as most of us - dealing with toyo ra1, r888 or similar r-comps, camber in area of 3-2 negative degrees, etc.

typical thing you do first if you do not want to replace shocks and keep using stock PASM - replace front LCAs (to get up to -3 deg camber), replace front fork arms to adjustable (to be able control caster), replace rear dogbones, replace rear toe arms (to get more control and prevent it from slipping). GT3 sway bars front/rear with custom (tarett) adjustable droplinks.

that is already like $3-4K on parts depending of what you get.

next step is to put proper springs (whole different topic which ones) and shocks - you will loose PASM here if you will want to choose from race grade shocks - Moton, JRZ, Ohlin, OR you can put in bilstein damptronics which are PASM-compartible PSS9 shocks.

total price of my suspension work with dual adjustable JRZ RS without external canisters and almost everything changed with GT3 OEM parts - LCAs, upper mounts was about of $13K or so which is somewhat on medium side for street-race dual purpose grade suspension. for track only suspension springs would be stiffer - not 600/700 but 900/900 or 900/1100 perhaps, shocks would have external canisters - JRZ RS PRO most likely, LCA ends would have steel monoballs, proabbyl would worth to replace wheel hubs to allow to lower car to cup car level, to get different fenders or roll up current ones - all in all may be another $7K or so. for me it is way beyond any reason, at least for now. but you can see what I am talking about here, right - you are starting to build up a cup car copy. I have stopped at base gt3 level minus brakes.

All this stuff is pretty expensive as you can see and usually custom built suspension works as good as good the mechanic is who puts it all together. I would really find a good tuner shop nearby who works on 997 gt3 cars as essentially you will end up building in gt3 suspension on your c2 tub.

utkinpol

also to add to it - you`ll need to decide on tires sizes and get proper rims.
I ended up with gt3 NB sizes - ccw rims in
18x9 +50mm (7" backspace), 18x12 +69mm (9.25" backspace).

those are imho widest rims one can fit without rolling up fenders into NB 997 car. it fits 265/335 rubber but 9" fronts are better with 255 tires.

one advice - if you decide to replace LCAs - replace both rear and fronts at same time, it will save you money, and if you want shocks - do that too at same time, as labor is not cheap and if doing it separately you will end up paying twice for same things - alignment, shocks removal, etc.

TAI2

Hey "utkin",

Thanks for the feedback. My plans are really beginning to gel thanks to you guys.

My last car was a dedicated track car that I trailered so I am familiar with the +/-'s but this car will, for now, be a DE/Street car. I generally do 14-16 track days and DD on nice days.

I will trailer the car and generally use R888's or similiar r-comps. Hoosiers are nice but to really enjoy them the suspension would be different as you say. I also have the option of driving to the track for the more local events.

Your typical scenario that you point out is where I am at: "typical thing you do first if you do not want to replace shocks and keep using stock PASM - replace front LCAs (to get up to -3 deg camber), replace front fork arms to adjustable (to be able control caster), replace rear dogbones, replace rear toe arms (to get more control and prevent it from slipping). GT3 sway bars front/rear with custom (tarett) adjustable droplinks." I am going to also change the rear LCA's and call it a day for now.

I do have a couple of choices for a local tuners that work on GT3's so I am in good shape. I am in Northern NJ.

For the wheels and tires I am sticking with GT3 NB sizes and have a nice set of CCW's that are 18x9 and 18x12.

I also have a 997 GT3 wing and now a front spoiler on the way. Hmmm, this car is looking just like a GT3 so some have asked my why I did not buy a GT3. Well, the reason is I could not afford a 997 GT3 and got a sweet deal on this 2005. It has 11,500 miles, is in mint condition, I bought if from the original owner for $45K and so the upgrades fit my budget.

Thanks again and I'll send pictures when I am done.

Tom