There was a black Friday sale when SPL had all their stuff on sale. I posted about it. This is what happens when people don't listen to me

Contact some of the vendors here. I used ImportPartsPro, they had the best price

https://www.importpartspro.com/

He was talking about the car darting. Not really ride quality. Excessive negative camber causing tramlining to be worse. I knew what he was talking about. Guess you didn't pick it up. Chill out, he is trying to learn.

I've got 5k swifts on the true rear kit. I'm fully aware of how the wheel rate is about .5 to 1 on a Z and the oem springs are basically double the rate for the same feel as a true rear strut spring.



yeah, I was hoping to hear something like this. the front and rear toe is in range of manufacturers specs, and camber is only off by tenths of a degree which makes it hard to believe just that alone would cause so much instability over regular street imperfections. I'm just not experienced enough to be confident that its just the alignment at fault here. But, then I'm also not sure if you guys that are running the aragostas (which are almost 3 times the price) is the reason you aren't complaining about ride quality. But BC is super popular in the community so I also can't imagine they are the reason either.

I'm running stock tires all around. Got the car brand new back in June and I still only have 3k miles on it lol. BUT..... since I spent a ton of time trying to settle on a setup I liked, I drove around without an alignment enough to chew my tread down pretttttty bad. I know I know, but in a way I'm almost glad I'll be able to get rid of these crap tires soon. Here's the current status:

Stock Bridgestone Potenzas
Front: 245/40/19 @ 40-50% tread and 32psi
Rear: 275/35/19 @ 10-15% tread and 34psi


EDIT: yes, as Spooler pointed out, the instability im talking about is mostly darting and tramlining where the car kind of jolts to the side following a weird bump in the road or going over painted lettering that's slightly raised on the road will even cause me to grip the wheel hard to maintain a straight drive which blows my mind. I may actually go snap some pics of some bumps I know cause this pretty badly to give you guys an idea of what I mean. This is all at normal driving speeds too, nothing crazy.

yup, fully aware of this. My oem kit I currently have on is at 8k that came with the bc kit, and the true rear kit I had before this was using a 5k swift.

I'll admit I was in a rush to get something to allow me to align the car (its my dd) and couldn't really understand just by quickly skimming the descriptions, photos, and feedback why there would actually be a difference. Clearly I was wrong. Lesson learned.

FWIW, I noticed my car came from the factory with some strange findings...

I picked it up from a dealer with only 7 miles on it so I doubt they messed with it, BUT....

1. The front sway bar studs were over torqued and borderline stripped, because when I removed the nuts on one side, they were VERY loose. Reinstalling the sway caused them to fully strip and I had to drill them out and replace them with bolts.

2. the bolt that goes through the midlink on one side of the car was oddly deformed in a way I've never seen before. Here it is compared to the one from the other side for you guys to scratch your heads at...

http://www.the370z.com/attachment.ph...1&d=1609358122

:icon14: :eek: :shakes head:

That bolt was way over tightened so bad it stretched. WTH

I think you learned a lesson or two about suspension components, but haven't we identified the problem right here?

Dead tires are going to have a MUCH greater affect than one degree or less of camber of fractions of a degree in toe

aint no coilovers, arms, or alignment thats gonna affect your car more than not having tread

yeah I honestly have no idea how it could have happened, especially from the factory. surprisingly it caused no issues at all when it was installed, just super ******* weird when I saw it

I really really really hope this is what it is, or at least most of the reason. I would really love to know and understand the technical reason for it though. Like how does a 100% tread tire cause the car to not dart around as much? does the softer rubber absorb some energy when it happens? does a balder tire act like a stiffer wheel?

EDIT: I was able to measure about 2-3mm of remaining tread on the rears and about 4 or 5mm on the front. I don't know what the original tread depth was but I'll assum its a centimeter, so that would technically mean I'm at 20-30% in the rear and 40-50% in the front but not sure if that really makes a difference

So far this is my plan of action...

- switch back over to true rear coilovers
- get SPL front upper control arms
- get SPL rear toe Arms
- replace Z1 camber arms with SPL camber arms
- new tires
- another alignment
- stop complaining

I know its a super debatable topic, but are my upper strut mount studs really at risk with true rear setup? They're welded to the chassis and if they ever snapped or stripped, I feel like I'd be ******. I also can't imagine theres a noticeable difference in handling even though that's the common rumor but still curious what you guys have to say about it.

True type makes for easier spring rate calc and adjustment precision.
If math is done correctly, and shocks and springs properly matched, there’s no handling difference.

Just make sure when you set your ride height the sway bars are disconnected. You really need to have the car corner balanced for best result.

hmm... curious why having them connected would affect height adjustment? I usually disconnect, or make sure both sides are evenly loaded/unloaded when working on the suspension because of unwanted tension if I didn't, but not sure why it would matter when adjusting the height? Is this assuming that the endlinks are adjustable (im still on stock endlinks for now)

@OptionZero @Spooler and @Rusty (and whoever else wants to chime in)...

Is there a reason to spend the extra cash on the billet versions of the SPL arms? Or will the regular titanium tube style versions suffice?

The regular will suffice. That is what I have.

Because I didn't when I did mine. I then took it to be corner balanced. Put the car on the scales it looked close. Disconnected the swaybar endlinks. It was way out on the scales. Ride height changed also.