Mixed use alignment? (Attn:Hotrodz, Rusty)
 

So been a while posting but I got a secondary vehicle so now making some changes with the Z and doing suspension arms and also some custom valved powertrix ultralites. I still plan do street drive the car so I’m trying to get some feedback on alignment thoughts. I know the go to for track is a -2 to -3 front with a -1.8 rear but I think that’s going to be a bit much front for any sustained street use. So then the question is if I plan to keep the front around -1.5 to 1.75 should I then put the rears closer to -1.25ish? I know factory has the rears more negative than front but then I see a lot of the Z (and GTR) change that ratio for aggressive use as you get more corner exit traction.

So keep rears 1.8 and just have less front or adjust the rear to keep a more negative front bias?

I've been using these setting for a while.

Front:
Camber -2.2
Caster 6.5
Toe 1/16" in

Rear:
Camber -1.8
Toe 1/16" in.

Been thinking on going to this because I don't track like I used too.
Front:
Camber -1.8
Caster 6.5
Toe 1/16"

Rear
Camber -1.5
Toe 1/16"

That looks decent. I’ll either copy that or do 1.75 ish all around

After trying out many different setups, I think if you go front between -1.5 and -2.0 and back somewhere close to -1.0 and -1.5 you are going to have a pretty neutral setup. The Z has much wider rear tyres, and quite a soft rear sway bar, resulting in a lot of understeer when stock. So I'd definitely suggest the front as mentioned above, and the rear somewhere between -1.0 if you have a stock rear sway bar. Or -1.5 to even -2.0 on the rear if you've got a very stiff rear sway bar.
For toe, I'd suggest 0 on the front, and just slightly closed toe for the rear. This proved to help return the steering wheel faster when going out the corner while keeping the rear neutral.

I am aiming for similar numbers. car is 2011 Sport on original suspension and I don't plan on changing over to coilovers or lowering springs, I plan to get SPL FUCA for the front. For the rear can I achieve that on stock hardware or will I need to add some bits to get there?

Stock rear doesn't allow less than -2° camber.

I guess to get there I also need to add rear camber links (SPL RLL Z34D) ?

According to this, oem rear camber is 1.58

Wrong. -1.17 to -2.16.


http://www.the370z.com/brakes-suspen...ent-specs.html

Oooooh you're right, my apologies! I forgot I have a lowered car which inherently increases the negative camber. My bad!

And to answer above - if you go out of OEM specs, you will need not just camber arms, but toe arms as well. Aftermarket camber arms will allow more or less aggresive camber, but will pull the toe setting out of alignment and just using the stock eccentric screw to adjust it will not be enough.

I’m on Stillen sway bars so I’ve actually increased rear to front in terms of % increase from stock. I know the go to is hotchkiss front and no rear but I tested setting the Stillen full stiff front and full soft rear and it wasn’t for me, just seemed steering response was gone and car only wanted to push.

Full setup will be powertrix ultralites lowered 1-1.25”, z1 forged upper arms with poly bushings, z1 rear camber arms with poly bushings, spc toe bolts and Stillen sway bars. Stock rays sports with either 10mm spacers (currently) or 20mm once I test for them. Looking for a setup that be good for hpde days a few times a year and then not destroy the tires on the street.

The more rear camber you have the less tire meaningfully contacting the road for straight line acceleration.

As soon as you get in the car, your weight adds more rear camber, then plant your foot to the floor and the rearward weight distribution adds even more. Pretty soon you only have have the first 4" of the inside of the tire really biting the pavement. *Facetiously speaking about the 4" measurement but you get the idea.

Yeah, the Z has a steep camber curve designed into the rear suspension. The more it squats, the more camber it gets.

I agree and unfortunately hurts straight line traction as a result so I run -1* on my dedicated street car to save the inside edge and keep as much width on the road as possible. IMO still handles great for my usage.

While mine is by no means a track car, nor even a auto X ride I take it to a road race shop to make sure it's "treated with respect", done "right" with me present, and I pay dearly lol.

I noticed the major amount of rear camber change when the tech. pulls down on the rear cross bracing while making adjustments! :eek:

https://youtu.be/20rltqTKeVE?si=5dMuIp0LF9Jx-q2A

Recorded this a while back to visualize the camber gain


Sent from my iPhone using Tapatalk

Good points but also have to take into consideration you’re jumping spring rates quiet a bit and also when bringing camber back into spec you’re shortening the lower arm (in the case of the rear) so now the upper and lower arms are closer in length to each other so you’re also changing the curve. Same happens for the front but instead you’re lengthening the upper arm. So all these things combined is typically why you run higher static angles (at least in other platforms) as there’s less geometry changes (especially when adding stiffer sways) so now the tires and tire roll have a great effect.

Unless you modify it and change the pickup points on the rear subframe. It works very well too.

How many here are willing to do that?

Well, it may break some rules for classes some folks are in. All good though.

IF you pull the rear subframe yourself and send it in it's not that bad of a price point. Or you can have them buy a subframe and modify that one.

Ok so got the project done over the weekend and picked it up from alignment today.

Ended up doing

Front:
Camber: -1.8
Toe: was either 1/32 or 1/16 I have to double check the sheet
Caster: 7.6

Rear:
Camber: -1.5
Toe: 1/16

Only got a short drive home but tracks straight and feels good so far. I’ll do a longer drive this weekend or Monday and get a better feel for it. Had them check corner balance and it was really good, only about a 4lbs difference left to right in front with my body weight in the car. Can’t wait for a track day now.

just picked up the car from alignment shop last night (added SPL FUCA, endlink and front Hotchkis) no problem in achieving following: (stock height)

Front
Camber -2, Caster +6, Toe in 1/16"
Rear
Camber -1.6, Toe in 1/16"

Now just have to tighten up end links, felt small clunk when I drove it. Alignment shop mentioned it too, Guess I did not torque them down enough.