I have perused all the related threads but have a couple of outstanding questions: Seems its possible to get up to -1.5 F and -2.0 R camber with OEM pieces on a GTS or SPASM 997. I'd like to hear from anyone who has done this, at those specs, is cording of the inside shoulders an inevitability if the car also gets used for a lot of freeway driving?

I ran GT3 LCA's on my 996 at had -2.8 F and - 2.3 R but that was with R-rated tires and a car that didn't get much highway use. On the 997 GTS, which will stay with street tires, I'd like to find a balance that doesn't wear outside shoulders to much on the occasional track day but doesn't cord insides on a 2000 mile road trip.

My strawman thinking right now is to max out front (get -1.5 if possible), set rear to just outside OEM range (say -2.0) and set toe to just a tad in (say +1).

 

So what i've learned after a couple of track days.
1) On a GTS 4 max achievable front camber my shop could get was -1.1*
2) That is not nearly enough for the track, even on street tires. Almost corded after about 1.5 days.
3) I now think the ideal street/track compromise for front camber is likely -2.0* area
4) This value should be achievable by split LCA's alone or by top camber plates (eg Tarett) alone.
5) But adding roughly 1* of camber via LCA's is borderline too much shimming = too much tension on the CV joints. That may entail driveshaft extensions which = more $$ and complexity.
6) Simple alternative seems to be the Tarett top plates, but...

.. questions to the group are:
- What are people's experience with NVH noise and reduced bump travel with Tarett plates?
- Is rotating the stock strut plate 180* (as was possible with 996's) a possible alternative if all I'm looking for -2*?

Thanks

 

I owned a GTS 2 wheel drive and ran into the same problems. My advise is to sell the car and get a GT3. You will have a better car in the end that is designed for the track.

 

Are you sure about this? It seems like the preferred route on the 997 platform for more front negative camber is to go with GT3 style two-piece LCA's. One degree of additional negative camber is roughly 10mm of shims. You could even use the 996 GT3 version LCA if you wanted. Just check for compatibility with your existing thrust arm bushing thickness (hydraulic ones are thicker than the rubber ones).

 

I understand 5mm of shims is the maximum safe amount before you risk CV joint trouble. So yes, I would want 10mm shims for that extra full degree, but that would then require driveshaft extensions. Seems with those constraints, and if all I want is -2* area total, the plates are the simpler path. I just have NVH concerns over elimination of the rubber in the mounts. Unlike my last 911, I want to keep very close to stock highway friendliness.

 

I hadn't heard anything about CV joint issues before for greater than 5mm of shims. FYI - Porsche sells a 7mm shim for the 997 GT3 (996.341.543.93).

Is this issue for both the 2WD and 4WD versions? Is there a link or reference you could post about this? I'd like to learn more about it.

edit:
OK, googled a bit. It looks like at extreme shim amounts the front CV joint alignment becomes a problem on 4WD versions only. But the references seem to point towards extreme front negative camber, greater than -2.5 degrees. You should be fine below -2.0 degrees with shims alone. Or if you have a 2WD GTS then no worries.

Good info here:
https://rennlist.com/forums/997-turb...59-camber.html

And here's a fix too:
http://www.tarett.com/items/996-997-...-10-detail.htm

 

I run a lot of front camber on my C4S, 17 mm of shims each side, resulting in a -3 degree front camber, I also have a Tarett 10mm shim on the front differential/CV to compensate for the added length of the LCA and relieve any stress on the CV's. http://www.tarett.com/items/996-997-...-10-detail.htm

While it is an aggressive setup for the C4S it is also amazing what it does for the handling and tire wear on the track.

 

No, front CV joints by definition only exist on AWD versions. As stated I have a GTS 4.

Thanks, this kind of actual experience is helpful. So, you CAnyonrs4, are running R-compounds on the track. I did on my 996 and found same as you, -2.8* at a minimum absolutely is required. But.. that was a track car I could street. Now on the 997 GTS I am super-consciously drawing a line and wanting to keep a street car I can occasionally track. I will NOT go R-compounds as that launches so many other track mod suspension requirements. Clearly, the -1.1* I have now is not gonna work even for the occasional single track day. But I'm guessing much over -2.0* camber in front will cord inside shoulders if the car sees a lot of highway travel. How do you manage street driving shoulder wear with -3*? Also, have you had any kind of driveability or maintenance issues at all with the driveshaft spacers?

My thinking is LCAs w shims + driveshaft spacers although more $$ may trump Tarett top plates for my purposes (ie target -2*) as they should keep stock strut NVH isolation, increase front track, keep top of tire-to-fender dimension less changed. Thoughts? Thanks.

 

If you don't want to install GT3 lower front control arms and use stock GTS SPASM suspension then go with -1.5 degrees camber for front and back. With street tires on a car that won't be tracked all that much no need to go with -2 in the rear.

It's not so much the negative camber that wears out the insides of the tires but the amount of toe. Very aggressive Toe will wear out the tires faster.

I've found that on these cars for street tires and even street drivable R-Compound tires that Zero toe front and -1.5mm IN per side on the rear...NO MORE than -2mm in per side works great. Great on the street and track.

Hope this helps..

 

mdrums is correct it is not the camber that wears out the tires but the rear toe.

I run Nitto's at the track and have very even wear inside to out with my camber settings. I also drive 80 miles to and from the track on the Nitto's. My street tires are also wearing just fine on a DD basis.

I find you need more camber on the track than the stock LCA's will give you even if you are wanting an occasional track car, street tires really need the camber given the softer sidewalls of some street tires I chewed through my first set of street tires with as much camber as I could get with the stock setup.

 

Can the Tarett plate installation be a DIY? Do you need a spring compressor to drop the struts? I have have a toe measurement tool so can self-align after setting the new camber.

I've done this job on past non-Pcars' coilovers (which dropped out easily as a unit) but not sure how 911 struts and the AWD might complicate strut lowering.