BeaverMeat

Looking to upgrade my suspension for asymmetric weight distribution for the best mechanical grip as possible. Haven't been able to find the raw data to make the proper calculation. I have gathered some knowledge from reading forums, but I am wanting to be exact as possible so I am looking for some help.

The car is a bone stock 2003 Touring 6MT. I'm wanting the car set-up with weight distribution without the spare tire/tools. I believe that will change the distribution from 53/47 to 55/45. I am not wanting to drop the car any more then I need to.

So far I have this set-up in mind and I'm looking for some feedback.

Espelir GT coils (384) in the front with Koni Yellow struts
OEM coils (342) in the rear with Bilstein B6 shocks

Unsure yet If I'm going to shave the rear seats or shim the front springs to keep the ride height consistent.

On a side note: Can I use G35C coils on the 350z? Is there a calculation to use to know what the drop will be? I noticed most coil manufacturers don't publish the spring lengths.

MicVelo

OK, I appreciate all of the science and thought you've put into this but.... helps to know the objective/intended application. Are you setting up for Track, Solo, street/mountains?

Not exactly sure what you are expecting to gain from changing the weight distribution to a nose-heavier config....

Honestly, I think you're overthinking it a tad. The Z33 isn't an F1 car. I can, however, understand your wanting to corner weight the car but this combination of hardware really isn't going to give you any weightjacking capabilities or advantages.

Besides that, you're neglecting to take into account roll stiffness with the setup as you've described. What you're suggesting will stiffen up the front possibly to an excess and will put MORE understeer into the car. Z33 likes a balanced chassis setup but again, depends on what you're after.

Elaborate?

dcains

iTrader: (15)

You'll need cockpit-adjustable springs and bars so you can adjust the balance every time you fill the gas tank, and as you're driving, and if you have a passenger, bring home groceries, as the tires warm up, to adjust for aerodynamic load and drag, and on and on. A silly excercise with zero ear-world effect.

BeaverMeat

Track driving... But I am also driving it on the street. Im not for one for the bolt-on placebo of "flush look" or "aggressive stance".

I guess asymmetric is the wrong term... Quasi-asymmetric. Essentially I want all four corners to have the same suspension frequency. Meaning, it takes approximately the same amount of force to travel the suspension on all fours.

I know adding stronger springs in the front will increase understeer. But that can be countered by tires, sway bars, etc. I prefer softer rear springs so the car can be accelerated harder out of the apex.

BeaverMeat

EDIT:

Noob mistake. It seems my information for front bias spring rates was taken from someone using coilovers at the rear shock mounting point.

I'm a driver not a tuner. So I'm lost until you stick me behind a steering wheel.

MicVelo

OK, someone who gets it.... You're right that the "look" factor of much of the available suspension equipment out there doesn't always "get 'er done" from a true performance perspective. And, your observation about countering steering attitude (over/under) with other mechanical advantages (tires, bars, etc) is spot on.

However, again, I respect your thought processes here; but do feel you're overthinking it some. Not a bad thing, mind you, just that there are established solutions out there that work already. And, as a self professed "driver-not-tuner", I'm sure you agree that "seat time" beats "think time". And I won't get into my usual "a good driver can compensate for a bad car" rant here. Laff!!

But OK, that all said, if it is frequency balancing you're looking for, hardly think that out-of-the-box shocks and springs are going to help you much to the degree that you're looking for; and you may set yourself up for disappointment unless you're willing to ante up for a set of Penske race shocks or at the very least, a good set of DA coilovers along with a lift and corner scales to keep the car on that edge you're looking for.

But in the end, I applaud the well thought out solution you ultimately come up with. Good luck with the set up. In for results.

BeaverMeat

The reason I'm overthinking the set-up is because I can't do a shakedown of the car easily. I could either go for a well calculated fixed set-up or a semi-calculated fully ajustable set-up (front coilovers, full SPL kit, and adjustable rear shocks... but $$$) the first option is more cost effective. Buy once, cry once.

What are the proven motion ratios for the front struts, rear coil, and rear shock?

What are the effects of using g35 springs on a 350z? Has anyone done so?

I'm still on the fence about shocks. I don't understand how to read damper dyno charts and I can't seem to find a database of all aftermarket dampers. One problem to solve at a time.

GreyZ

iTrader: (2)

Im a bit confused here, the calculation part is free. So a non adjustable setup or a adjustable setup are the differences. If you are saying that you don't want adjustable arms because you don't understand how to adjust them, there is a suspension 101 thread that will explain it all pretty well.

The motion ratios are not adjustable (unless switching from oem rear location to true type location) There are established htz rates for track and street. A true track car would beat you up on the street though.

Once you are this far into spring rates and free lengths, it doesnt matter. They will fit because they are the same mounts. Find what rate and length you need and go from there.

Shocks are by far the most important part. Pick your spring rates and then get your shocks re valved to match. Or pic the most shock you can afford and contact the manufacturer for the range of spring rates that the shock can handle optimally.