BULL

Glad to know the islolator worked. essentially one could play with it's thickness to match the height desired. Don't think it could get better than posted.
Thank again for this!

backman_66

You're welcome! And thanks for the compliments. Its actually settled a tiny bit more so the effective bump in height was about 3/16 - 1/4". Still not as much as I'd hoped for but it will work! But like you said, one could order a thicker one and get more height out of it.

backman_66

I have a little more information I'd like to add to this post. After doing some more research to find out exactly what the differences in spring rate are, I think I may finally have the answer. It was very hard to find any information on the stock sport sedan RWD spring rates. I'm a bit of a numbers guy so I like to know exactly what changes were made to my vehicle when replacing springs like this.

370Z NISMO SPRING RATES (pre-2015)
This thread lists two different spring rates in the first two posts: Spring Rates - Nissan 370Z Forum
8.1f / 9.1r or
8.6f / 9.3r

I am not sure which is correct. Both rates are pretty similar though. I would go with the second choice because the guy claimed to be an Indy car chassis designer and tuner and he said he actually tested the rates himself.

G37 SPORT SEDAN RWD RATES
This is where information was extremely lacking and I only stumbled upon this by chance, but there was 1 guy I found that tested the rates here in post #13: https://www.myg37.com/forums/brakes-...rwd-coupe.html
8.4f / 7.8r

IN CONCLUSION:
The rates seem very accurate from what I can tell after changing springs. I mentioned this in other posts above, but the fronts seem VERY similar between the two and the rears are definitely firmer.

And once again, the front drop is 3/4" and the rears are about 1 3/16 - 1 1/4". But with a modified isolator solution, the rears on my car are about 7/8 - 1" drop now.

Thanks for reading, hopefully anyone wanting a cost-effective, mild drop can find this information useful! This cost me a little over $150 for the springs and isolators.

RobC7

Thanks for going through with this! Car looks sharp with the current wheels & ride height. I've seen a few sets being sold with the stock front shocks, I wonder if that would have any additional effect on ride & height.

So after driving it for a few weeks, how does it feel? Does the car feel any flatter around the turns? I know with my stock suspension it feels like the rear compresses quite a bit during acceleration, do you still have that same feeling?

backman_66

I wouldn't use the nismo shocks unless you want a really bumpy ride. I've heard they're pretty harsh.

Considering the weather hasn't been too great and it's not my DD, AND I haven't gotten it aligned yet since I've been getting the ride height honed in... I haven't had much driving time yet. But I will say that I have taken some corners and the rear felt so much better and I know I could have pushed it harder , more comfortably than before. It's a definite improvement! The rear felt much more planted. I'm going to play with it some more once I get it aligned and I'm also going to test switching my front eibach sway from the soft setting to firm.

Overall though, it's hard to say because I also put on those lightweight 18's recently and haven't really had much time to test those either. But the combo of the wheels and the nismo springs has drastically helped and I'm really looking forward to putting in more time driving it.

RobC7

Thanks for the info!

Contemplating this setup or possibly Swift springs with the added isolator out back. Car is parked for the winter so I have some time to think it through.

backman_66

I had the car aligned today. I'm a little bit concerned with it though because from what I've read, I thought I remember people on these forums saying the fronts can be adjusted for camber and toe from the factory.

The guy said he didn't see a way to adjust the camber (Edit: fixed) in the front? Can someone please tell me if the toe specs are okay? I know the rears are fine but I'm concerned for the front. This is with the front and rear lowered about 3/4" - 1" with the nismo springs.

FRONT
L: Camber -1.0 and Toe 0.06
R: Camber -0.9 and Toe 0.07

REAR
L: Camber -1.3 and Toe 0.04
R: Camber -1.1 and Toe 0.03

He said he likes to leave a little toe in for the rears, but I assume he could have gotten it to 0.00 considering there's room to play with the camber. Please chime in and help me so I'll know what to say if I need to go back. He was a nice guy and said I can come back if it doesn't seem good.

2.2Lude

iTrader: (1)

I haven’t gotten under my G yet, but I’d have to assume front toe adjustment is done at the tie rods like nearly every other car, no? You’re within spec though I’d prefer 0 in the front.

Your guy sound like he sort knows what he’s talking about, rear toe in is indeed advised. Helps when the back end squats under power to keep better traction.

JSolo

iTrader: (14)

IIRC, front is toe only, rear is camber and toe.

I tried looking for the alignment printout from the last time I had it done on the car (10/2015), all I found was just the receipt for the work

backman_66

I called up there and talked to the tech again. Sounded pretty knowledgeable. He said with radials on these types of cars, if you set the toe at 0.00, they usually have some sidewall flex and it'll actually make the toe go negative and it will cause extra wear. So he usually sets most cars this way for best tire wear. He said we could still set it closer to 0.00 if I want but this is usually the best compromise between tire wear and performance.

Hugh Jorgens

Every car I can think of in the universe has front toe adjustment via the tie rods.

Optimal alignment angles are somewhat complex. It depends on wheel offset, intended use, tyres, etc.

A general shop is going to get you into the green. That's good enough for normal use.

With your lower offset wheels, I'd want some front toe IN to fight the increase in scrub radius and to even out any potential wear from camber.

Same with the rear...but some toe in on the rear. Rear toe in also increases stability in straight line cruising because its always centering the rear of the car. Almost every passenger car comes with a small amount of rear toe IN.

Additional info...as the suspension compresses...
the front will camber IN but toe OUT
the rear will camber IN and toe IN

There's no front camber adjustment directly. But if you take the inverse of what I said above...

Toeing the front IN would cause some positive camber too, because all the angles are dependent.

Toeing the rear IN would also cause camber to travel negative.

I would run:
Front:
Toe - POSITIVE 0.06 per side (+0.12 total)
Camber - What you get is what you get.

Rear:
Toe - POSITIVE 0.08 per side (+0.16 total)
Camber - It will be negative. But anywhere from 1 to 2 degrees shouldn't need your attention...especially with the static toe spec being slightly positive.

Looks like your bwoy got u pretty close.

I wouldn't be unhappy with that. You usually don't want 0 toe.

backman_66

Hey man that's some really awesome info! I'm glad you're smart enough to factor in the difference in scrub radius with different offset wheels. So it sounds like my front and rear toe should be just fine, although the rears could go a little more toe IN if I wanted. Lol, you guys should know me by now, I'm always overthinking things and being paranoid with the way it's set up. I'm just glad you guys are here to offer some more technical knowledge than I have.

backman_66

I just looked at a tire size calculator and it says my front scrub radius is about 12mm positive. Doing a quick search on scrub radius' effects on toe.....:

"Scrub radius affects the tire’s tendency to change the dynamic toe angle during braking and acceleration. The effect of positive or negative scrub radius on the toe angle will depend on whether the vehicle is a front-wheel or rear-wheel-drive design. The manufacturer’s preferred toe specification is determined by the force created by the scrub radius.

Rear-wheel-drive vehicles typically have a positive scrub radius (mine is 12mm positive over stock). The vehicle’s forward motion, combined with friction between the tires and the road, moves the front wheels back (toe-out). The manufacturer’s specification will be slightly positive (toe-in) to compensate."

But of course that's only during braking and acceleration. I'm not sure if it would have much effect during cruising?

Hugh Jorgens

Too much static positive toe is going to make the car feel sluggish. More than too much is going to cause erratic steering.

Any amount of toe in either direction is going to add to tyre wear. Toe in tends to even out the wear, however, so it can be used as a tool to do that.

Anyway...
Cruising = Acceleration. You can't cruise in neutral...you'll decelerate. To keep a constant cruise on a flat surface...you're always giving it a little gas.

Meaning you're always pushing the front tyres into toeing OUTwards. So you want some static front toe in. As it cruises, your dynamic toe ends up closer to 0. KnowwhatImean?

If you're accelerating hard...the rear suspension squats and the front extends.
meaning...rear toes INward front toes INward.

If you had too much static toe in to begin with...you're going to have an excess when accelerating.

Decel...
Rear extends, front squats.
So rear toes OUTward. Front toes OUTward

You want enough static toe IN so that you dont get excess toe out in that situation.

Again, that's why manufacturers set a range of acceptable values.

I think your alignment is good as is. But...do some reading and decide if you want something else.

backman_66

With the cruising thing, I just meant that the effect of cruising will be much less pronounced than accelerating from say, a stop light to cruising speed.

Thanks for all of the info! You've eased my mind and my wallet. Lol