Peter_GT4

Looking for some advice for a proper track setup with moderate use, 2-3 trackdays a year and the rest is just some fun on country roads, what are
your thoughts and experiences so far?

The plan is to have an alignment done before the first trackday, since the factory setup is often quite off and some complain about bad handling/feedback
and unforeseeable changes between over- and understeer.

While at it, I thought I might give her some more camber via shims and adjust toe accordingly. Advice where to go would be very welcome, also regarding
ride height and ARBs.

In the GT4 section, I found some very helpful sticky setup thread and the results turned out great, big thanks to RL! Now the GT3 should get the same treatment...
sorry if I overlooked some existing thread, so far I couldn´t find anything.

Peter

Frenzyy

Peter_GT4

Thanks Frenzy, that confirms my thoughts about factory alignment and the need to fix this. Any experience so far with the new setup?

Peter

Mr. Turtles

Even with a lot of track days planned I'm not far off of your set up. After reading a lot I decided to not go to far with alignment changes. I went to 2.5 camber in front though. Rest is pretty much the same you noted with slight toe out inf front and slight toe in rear. I had great results after 4 track days on the stock tires. If this set up works well on street for you well you have winner than for both street and track. Another friend ran Hoosiers with same set up and similarly good results. Some others have mentioned that they played around a lot with the .1 set up without much benefits and will be going closer to stock on the .2 even with lots of track use.

Peter_GT4

OK, trial and error, I´ll do so and report ;-)

Peter

Frenzyy

Haven't done track day yet, last track day was a down pour so give it a miss. will report back here or another thread once I get out there.

Turtles: did you get 2.5 at the front OEM parts? I originally wanted more but wasn't possible without castor pucks and front bump steer kit

Mr. Turtles

I did add pucks (Tarrett adjustable thrust arm bushings) but no bump steer kit, not sure what that is. I thought the caster pucks were needed because for the track I'm using 19 inch rims (OZ Superleggera from 997.2RS) which I thought was the reason for the caster pucks. The pucks didn't really change the ride in my view.

I thought with the OEM wheels you wouldn't need pucks even if you added camber but I can't confirm for sure. I thought some of the wheel reps were saying with their wheels I would not need the pucks but I got such a good deal on the OZ's I couldn't turn them down.

C4SGRPDK

The pucks are just to correct the caster when you shim the control arm.

You shim the arm to push out the front wheel, it increases the front track and allows for more camber.

unfortunately, the way the control arm is angled towards the front, it pushes the front wheel forward when you shim it, which can cause the tire to rub the wheel liner

the solution is either:

cheaper and harder to adjust - the pucks (like tarret, rss, BBi etc... also called thrust arm bushing https://www.bbiautosport.com/product...hing-kit-4fs3k )

or more expensive - the thrust arm link (BBi https://www.bbiautosport.com/product...-arm-kit-t595r)

you can do both but only if you want to remove all rubber from the suspension to make it more direct.

Peter_GT4

So, some update: Alignment has been done with 2° camber in the rear, 2,4° camber front, 0,13° rear toe per side, zero toe front.

A trip over some country roads revealed three things:
-better/more precise steering feel
-all good on even surfaces
-not good on bumpy roads. the rear seems in motion when hitting bumps in corners, like a bump steer effect
(only from the rear, the steering is not affected by bumps)

Where did I go wrong or overshot it? Too much camber, not enough rear toe (stock, it was set to 0,25° !) What´s the cure? Totally unhappy right now

Peter

Taffy66

The new GT3 is very sensitive to weight transfer which probably is not causing your problem..The re calibrated RWS is also extremely sensitive to any rear toe alignment changes..In your case i would first of all get rear toe as close to zero as possible to see if this cures the wandering you're experiencing on bumpy roads..

Peter_GT4

Sensitive she is indeed

Are you sure with zero toe in the rear? I came from significant higher toe-in (0,25) to 0,13, doesn´t that indicate
it needs more toe again when it was better in stock trim??



Peter

Taffy66

My GT3 is still at stock settings until i get very reliable guinea pigs to do all messing with alignments as i hate experimenting myself..I'm pretty impatient and have a very low boredom threshold..However i know of some very experienced track guys with the new GT3 who played with the alignment pretty much as you've done with the same results..IIRC the conclusion was that the newly re-calibrated RWS is overly sensitive to even minor changes to rear toe causing this instability you speak of..By increasing rear camber you have inadvertently messed with the RWS..I seem to recall after much frustration that one guy adjusted the toe at the rear to solve this issue..
It was a while ago and i'll try to dig it up tonight and post a link but he did manage to solve it in the end..I take it the tyre pressures are spot on with you as even the slightest imbalance again will play hell with the RWS..
I strongly suspect the new RS will be even more sensitive in this regard..This is the trouble when Porsche feel pressurised to improve on the ring times with each successive GT3..

Peter_GT4

Sounds like going back to stock/recommended settings in both camber and toe is the best way out of this?

I have to say I am even more confused since the factory settings were quite off from the recommended settings
(a lot more toe-in front and rear, uneven camber left/right). Even that seemed to work, I hope the return to factory
specs will solve the issue. I am not the guy who likes to align twice a week

Peter

C.J. Ichiban

Peter what are you doing with sway bars? I'd leave rear toe as close to zero as possible to avoid jacking the RWS algorithm.

If you stiffen the rear bar one hole, it will allow the car to rotate a little better. Will also help off throttle steering transitions through esses/ chicanes)

For bigger gains in low speed rotation, you can experiment with raising the rear ride height 1-2mm which allows the car to be looser through hairpins.

In general the Gt3 platforms have always suffered from "showroom snowplow" due to lack of a real alignment on initial PDI. Most dealers do not laser or string the car for symmetry. And lots of rubber bushings= weird settings.

In all of my setups for GT3 cars we always tried to max the front camber and used a combo of:

tiny toe out front (turn in)
Rear bar stiffer (rotating assistance/ midcorner)
Front ride height lowered 8-10mm (slightly improved brake dive and turn in)
Solid bushings (setup stays the same and does not deflect under load)
Upgraded/ lengthened lower control arms (less deflection)
Shims to set up the proper camber/caster ratio (consistent / progressive steering)

You generally have better luck by sequencing the medium strengths into full strengths handling wise to get the most gain. If you over-correct the weakest link it could compromise the strong characteristics of the car...rendering the platform untrustworthy.

DK7