limitedslip

Ahah yes, there's always the option of dropping it off somewhere and handing off a bunch of cash!

I guess the GT3 guys aren't very DIY oriented? On my previous cars people would share settings/usage/driving level etc. FWIW I can figure out and fine tune how much camber I need myself with a temp probe after a run and that'll be more precise than a tech making an educated guess based on how I tell him I drive.

Anyways if anything, I'd like to get in the ball park before bringing it to a pro for final touch ups and precision adjustments.

AEsco48

+1

AGO

^
That's what I intended to do when starting the thread rather than going blind...

mooty

there are no cars like gt3, ine teeny bit off, the car ain't the same
my car is aligned every track weekend
if u want a ball park figure
I run -3.75 fromt
-2 rear
one from full soft f
one from full hard rear
more rear toe than most ppl
toe out front
very aggressive lsd
it depensa on where, how u drive
what tires u are
so there is not starting point really

Spyerx

This was the point I was trying to make...There are lots of DIY people here, I'm one of them, but geometry is one I leave to the shop... and since you aren't the first owner of the car (and it looks like its been aligned based on the lower arm spacers in your pics) getting a solid baseline that is alined and accurate first would be key in my book. Then you are free to adjust all the settings you want one at a time. You can search on alignment here and get 100's of hits. You can also look in the manual and see the specs he factory suggests as a starting point (most here go more aggressive).

But w/o the proper tools... I watch the chassis guy at my shop do an alignment/balance for a new client and it is a very time consuming process. Like mooty I have mine checked after events. Small tweaks are made event to event based on my feedback and tire wear.

This is the basic of mine, does not include: Caster, bump steer f/r, ride height, rake, corner balance, track f/r, shock compression/rebound settings, caster angle (those puck things), pivot points of any of the eccentric bolts, wheelbase f/r, diff. My front top plates are rotated, I do have spacers on bottom and tops adjusted accordingly.

--Camber -2.5 rear
--Camber -2.8 front
--Toe .5 front
--Toe 2 rear
--Ride height slightly lower than stock
--Rear GT2 bar middle
--Front bar 2 from soft

This is a really good thread where TPC Tom shares many of the subtleties, it's a long thread but worth the read:
https://rennlist.com/forums/997-gt2-...me-07-gt3.html

Tom@TPC Racing

Agree with mooty and spyerx. Factors not taken in consideration by most people when flipping the top plates include change of roll center, ride height, available shock travel...just to name a few. The strut tower surface is not flat! It is angled. Not saying flipping the plates is no good but need to understand the affects. Working with your local professionals is ideal.

AGO

Mooty, Spyrex, Tom and all

Thanks for the feedback.
I believe I'll make small changes at this point on increasing negative camber to improve the wear on the outer edge of the tires. I was running MPSS and switching MPSC2 now as the outer edges on the SS were killed.
Shims only is my takeout, avoid affecting too much the other parameters as (to me) my car feels reasonably balanced -> no radical changes while I keep learning...

997gt3north

you have worn out the outers of our tires and yet you have shims in the control arms - which would imply, almost certainly, you have front camber more than -2?

my question is, do you actually know your alignment specs? (I ask because it sounds like this is a new car)

for a combo daily driver that will be running street tires, (-2.3f with zero toe, -1.8r with 2mm toe-in) is a good hybrid setup

the above camber specs, with the proper tire pressures on track days, will be fine for the level of grip the tires can deliver

once you go above -1.8 in the rear, you really accelerate inner tire wear during street driving - once you are using Hoosiers on track you can go a little higher but 325 Hoosiers at -2 camber is a lot of grip - if you are a pro level driver then -2.5 rear camber on Hoosiers is doable

AGO

Thanks, in fact I have 1.7 front and rear (no shims, those are from limitedslip post), with 0 toe in (front) and 2mm toe in on rears, and killed the outer edges on the MPSS as I got faster this year (inner side of the tires are still quite good). My previous alignment was 1.7 front, 1.5 rear but I was slower... so no tire issues then.

How's the balance on the "hybrid setup"? If quite neutral, I would probably adopt it, which sounds achievable with shims. Maybe a bit of toe out on the front for better turn in?

I'm using less the car on the streets as you are so far off the limit that it does not make too much sense (I live in Houston - very boring to drive here!) so to get some additional wear on the inside for street should not be a concern.

Spyerx

When I first got my car setup and started tracking, I was seeing OK wear, then I got faster (I'm still SLOW) and I started wearing outside, so dialed in more camber and tweaked other items based on feedback I had for shop chassis guy. The way mine is setup right now has great turn in, a ton of rear stick, no push, and tires are wearing very even. Of course, I don't do a whole lot of street miles but I do suspect the insides will wear pretty fast. It's a balance and a compromise unfortunately! I suspect as I get faster I'll need some more negative front. Others here run quite a bit more than me but they are also driving the car much harder and faster than I am right now.

Mvez

damn....full race!

997gt3north

After, many, many tweaks, I found my recommendation to be about perfect for the car that sees DE / track-days but is also somewhat occasionally driven on the street - if you do quite a bit of street driving then every .1 taken off the rear really helps a lot on inner rear tire wear.

Everything is a compromise but with MPSS or MPSC you will not shred the outside fronts if you get to -2.3. ZERO toe in the front is a good compromise when a car sees street driving as darting around on cambered highways gets old very fast - from there, you just need to find your sway settings that match your personal rotation preference and home track / autocross needs.

Once the car gets retired for more track duty it comes down to your skill and the tire's grip level but you end up closer to -3f (or higher) & -2.5r with very sticky tires - but by that time you will have shops involved and lots else going on.

Jake951

I have arrived at essentially the same alignment specs for my GT3 that is 50/50 track/street. I used pyrometer readings and observed tire wear to get there. Tires are Yokohama AD08R's.

mooty

well,it was stripped and on slicks.
this as I emmtiojed , too many variables.
u should take out 500 lbs in that pumpkin. total
y different car!

limitedslip

That was me (bolded part and the pictures).

Based on your comment I assume that there are no shims on the LCA on the car stock?

I do not actually know my alignment (I have receipts but no specs unfortunately). I tried hooking up my camber gauge but found out 19" wheels are too large for that camber tool. Anyways, from my experience eyeballing I would say there is ~ -2 front and it's eating the outside of the tires.

I'm not terrified by the idea that changing camber will affect other settings, I am aware of that. It's just that where I stand it looks like the tires are begging for more camber so that's what I want to do, add camber. I was asking what the easiest way to get there (ie add shims or turn top mounts) so that I can continue experimenting, feeling the car, tweaking and having fun...

Thanks for the replies