Track Alignment
 

Hey guys, I’ve searched through the board and seems everyone is running less than -3 degrees camber up front and -2 rear for track. My alignment shop however recommended -3.7 front and -3.0 rear on my car. Is this too much even for a track only no DD Z?

My setup as follows:
KW competition 20k f 18k r
SPL all arms
275/35/18 RE71R square

Thanks

-3.7 is too much for for 275 RE's I had -3.7 after my first autocross alignment with 285 RE's and the inside of the tires were getting much hotter than the outside. I adjusted them to -3.1 for the following weekend and the temp across the tread was much more uniform. I settled for about -2.0 for the rear which seems to keep temps on the back pretty even. I am curious how my car will collect OPR, which may alter my preference. Also, I'm running about 6.2ish degrees of caster which will also make a difference.

Thanks, so checking tire temps across the tire is the key. Should the outside be hotter? I was trying some used 305 slicks all around and the front were close with the inside being a tad bit hotter (~3 degrees celsius). But the rears were about 10 degrees (Celsius) hotter on the inside. Plus the rear were sliding out every corner exits, don’t know if the tires are done or my rear dampening is too stiff...(front Hotchkis, LSD and rear sway disconnected)

Thinking of going back to RE71R now.

Do you have true coilover setup at the back?

The front camber looks good for slicks, I would prefer less at the rear. As for extreme summer tires, I got luck with around -2.7 front camber and -2.0 rear, 0 or a hair toe out front with stock rear toe in value, and around +6 caster.

About rear sliding, maybe too much rear toe in.

You want the tire temps even across the tire if possible. I would use this to set your alignment to. But if you run on a different track. The alignment might need changed to suit.

Slick can run a little more camber, but not much. Dial in your caster to +7, more if you can get away with it.

The Z has a weird camber curve built into it's rear suspension. The more it squats. The more camber it has. It's not linear. My 2 cents. Anything more then -2 camber is a waste unless you tire temps are even across.

Also, you can play around with tire pressure too.

Get a big 3 ring binder and keep track of all the changes you make. Keep notes on everything.

I have divorced setup in the rear, will lessen the camber in the rear to around -2 first.

Thanks Rusty, I’m currently at +6 caster, is there any cons for going +7?

No.

So the rears aren't that hard, it may even be on the soft side, as most divorced setups focused on track have an equal or stiffer rear spring rates compared to fronts. I would suspect camber + toe in. I used to have a lot of toe in rear, around 0.9 total toe in, and the rears were sketchy and love to slide even with semi-slicks, getting it down to stock toe in value made it very sticky even with street tires.

Second guess would be very low rear height which mess the rear geometry.

People don't realize this when they lower the rear. The rear camber curve is not linear.

Yes I am planning to raise the height a bit as it is quite low. My spring rates are quite stiff at 20k front and 18k rear. Should I set the rears height a bit higher than the fronts?

My rear slicks were somehow sliding a lot at the last track day, I thought the tires were done. My rear toe is at 0.07

http://www.the370z.com/members/2011-...03-14-2018.jpg

This is what I use, if it were a dedicated track car I would be in the -3 something range and lower ride height. I still are destroying the outer edges of my tires on the track.

I run wide tires 315 square -3.3 front and -2.0 rear all with a tad toe. Caster is 6. If you are not doing tire temp in the hot pit after the tire is up to temp then forget about it. Play with your tire pressures. It is the easiest and most consistent way to adjust to conditions for those of us that don't have team of folks to help us and is still a what the big teams do. Once they have temps were they want them they play with tire pressure to dial it in.

I wish only camber curve, even toe adjustment range change with your camber value, less camber means higher toe in range to play with, due to its multi-link suspension design.

Your toe looks alright, suspension stiffness wouldn't have any issue, I run 21kg front and 7kg rear truetype (don't know the exact equivalent for divorced but should be in the range of 14-18kg) and it tends to understeer with equal height, I need to get my rear higher to get more balanced setup.

Maybe your assumption is right, old tires, as slicks performance depends a lot on heat cycles and storage. With re71r, you should be good with the alignment mentioned before.

I think coilover setting are dependent on the manufacture and their setup strategy. I run Fortune Auto true type rear 12k and front 14k. I am lowered about an inch an may go lower another .5 or .75. I find it hard trying to get it dialed in. I get better turn in down low and it seem I get more oversteer at higher ride heights. I also have a big wing and a front splitter that extends about 6" from the front bumper. All of those things impact how the car will handle as well.

how the **** is a 315 front on a 18x11 +16 not destroying your fender under compression?

As someone else who has run 315's up front, all I can say is it just works. As long as you don't slam the car and make sure the upright to wheel/tire clearance is minimal, you'll be fine.

Now if you want to get real crazy, you can run 335 on 18x12's square like I do. With that said, you're not fitting the 335's under the factory fenders up front.

I have neither the skill nor the power to justify a 335 tire, but salute for cramming that under the fender.

I scrounged together a set of 18x10 +22 (f) and 18x11 +16 (r) used Enkeis and was going to run either a 275/285 stagger or a 265/295 stagger, but i just had the fronts inspected and there appears to be a crack in one wheel that was repaired. We're gonna do some testing on it to see if it'll be straight and hold air, but i'm not really taking chances. I am leaning toward buying a new set of fronts

Thinking about 18x10.5 +22 which is plenty safe and will easily fit a 275 or 285 front and i can go 275 up to a 315 rear if it comes down to it. Some options and should be no danger of rubbing, since i'm already rolled and pulled in front.

I'm already at -3 f and -2 r so my alignment is probably track ready, its the height i need to look at.

then its off to swap fluids and brake rotors/pads and safety equipment

With 335's, you're not really under the fender anymore.

https://live.staticflickr.com/65535/...266af1ae_b.jpg

LMAO, as gomer said it just works! My off set is actually +18, not much of a difference I know. I have yet to have them rub even in a full spin or going over humps. My compression on the coils are set to full stiff as well for the track. I also run a set of Einke 18x10.5 +30 with 15mm spacers in the rear. I have not run anything more than a 295 on them but I think they would be fine with a 315 as well. When I got the first set of two 18x11s they had 305 40 Nittos on them and I test fitted them on the front and believe it or not they did not rub lock to lock. I was very surprised and excited so I ordered the other two and never looked back.

Mine poke about a half inch up front as well. I have been thinking of going with a 18x12 rear and 18x11 front and run 335 and 315 setup!

Remember I run a 20x11 +15 w/ 275/30 as my daily/street setup. It's fine, no issues.

Maybe I should suck it up and just get a matched pair of 18x11 +16 to parallel the rears. With a 275 or 285/35r18 it's a much shorter tire anyways. I have a 14kg front spring

I think you would be fine with that setup. It seems the standard table fair is a 18x10.5 square with whatever offset as there are many that work. Many run 275 40 or 275 35 square.

Sent from my SM-G965U using Tapatalk

Are you guys using TPMS on your track-only wheels?

AFAIK, a lack of signal just triggers a warning light, but won't cut power or anything

I don't run any.

Sent from my SM-G965U using Tapatalk

None here either.

I don't use tpms as well.


About wheels, I am on 10.5+18 and it rub slightly on hard right corners with -2.8 camber, but my left side is lower due to corner balancing. I think some go with +22 and +25 with 10.5 to avoid any rubbing, but I didn't roll my fenders, I think I will not have any issue if I rolled them.