Holy Understeer!

Originally Posted by Rusty

Question. Will this car ever see the track? You said that you are getting understeer in the twisties. So it's street. Track set-up on the street will KILL tire life. Pick your poison. You screwed up on your front tire size. Should have went with a 275/35-19. And now you want a work around. Ain't going to happen. Get the SPL upper control arms. For the street. Front camber at -2.0, caster at +6 to +7, toe should be 1/16" in. Rear camber at -1.75, rear toe at 1/16" in. If you set the rear toe to zero, and out. You will get a condition called snap-oversteer. It doesn't happen all the time, but when is does. You will be cleaning out your shorts! It's scary when you are looking at the guy behind you, eyeball to eyeball. Front sway bar full stiff, rear bar full soft. The front of the Z has too much roll in it. You WILL have to change the dampening on your coilovers. If not. You are SCREWED! If you are not willing to make changes. You are doomed!

My set-up. I'm running bigger tires then most anyone.

Front 285/35-19 PS4S on 19x9.5, +25. Rear 345/30-19 PSS on 19x12, +28.
Front camber -2.5, caster +6.5, 1/16" toe in.
Rear camber -1.8, 1/16" toe in.
Hotchkis front sway bar, stock rear sway bar.
Rear diff is a OS Giken set-up at a 1.5 way, with 70% lock up.
My whole suspension is out of the SPL catalog. No rubber bushings.
I turn off my VDC and have done the YAW sensor mod too.
My Z likes to dart around. It's a bit nervous.

Originally Posted by Hotrodz

Show off!!!

This is a great place to start and works well for a dual purpose track and street car that sees some twisty road time. If you are just dd the car there is nothing wrong with having front camber at -1.0 to -1.5 to extend tire life and if you want to maximize straight line speed....well that's a whole other story.

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Originally Posted by Rusty

Front 1/16" toe in.
Rear 1/16" toe in.
It's a bit nervous.

Originally Posted by Tractionless

What's 1/16" in degrees? Everything else I've read around the forum etc. notes Rear toe MUST be double the value of the front.

FWIW I'm running 255 fronts 325 rear aggressive street only, no track. All OE suspension other than front sway bar and rear adjustable camber/toe bars. ZERO understeer and the tires won't unevenly wear as bad.

Caster 5*
Front camber (not adjustable) -1.02*, -1.23*
Front toe 0.09*

Rear camber -1.04*
Rear toe .018*

Originally Posted by Tractionless

What's 1/16" in degrees? Everything else I've read around the forum etc. notes Rear toe MUST be double the value of the front.

FWIW I'm running 255 fronts 325 rear aggressive street only, no track. All OE suspension other than front sway bar and rear adjustable camber/toe bars. ZERO understeer and the tires won't unevenly wear as bad.

Caster 5*
Front camber (not adjustable) -1.02*, -1.23*
Front toe 0.09*

Rear camber -1.04*
Rear toe .018*

Originally Posted by igota21incher

How is that even possible? No understeer?

Originally Posted by Rusty

Toe in inches is the old way. The way I was taught doing alignments many years ago. Also toe in inches is affected by size diameter. Where in degrees is off of vehicle center line. Tire diameter won't affect it.

So 1/16" toe in with a 27" tire is .1326288 deg total toe. Or .0663144 deg for one wheel.

For the rear toe. A lot of the track rats here run close to zero toe on the rear. Helps the car rotate.

255 front, 325 rear, and no understeer? You really haven't pushed all that hard.

Originally Posted by Tractionless

Thanks for explaining the inches measurement, interesting substitute.

I guess understeer is subjective. Sure if I go 100 mph into a round about I'll get understeer but for the purposes of the OP, which are spirited street/twisties driving I do not have any.

Give me a legitimate scenario to test and I'll do so. As mentioned above, such a test won't be 100 mph into a round about as the most track savy Z on this forum will even understeer in such a circumstance.