Spring rates and roll resisitance on an S14

[sean350z]

Ok, i'm researching coilovers right now (Zeal function X and Zeal function D) and since i haven't had coilovers on an S14 chassis before i'm wondering which spring rates are the best for oversteer/understeer, roll resistance, overall handling.

Alot of drifting suspension setups seem to be a 'marketing' ploy that being the big word DRIFT makes them cooler and more marketable. That being said, the two setups, Function X and Function D, are pretty similar other than spring rates and what they are made of.

Function X - steel tubing, 8/6 spring rate, inverted
Function D - steel tube front/aluminum rear, inverted front/monotube rear, 9/6 spring rate

So my question, would a spring rate that different from the X to the D really affect roll resisitance and steering conditions on an S14 chassis?!?! This S14 project will be a weekend racer, barely a daily driver, maybe a drifter if i ever want to learn how to. That being said, which do you think I should go with? Pricing wise they are similar and I'm getting a killer deal on both shipped to me directly from japan and i don't have to wait a month :)

[Jefferson]

I would probally go with the X's just because they are all steel. I don't think there will be that much of a roll difference between the two spring rates( since only the fronts are stiffer and the rears have the same rates, but you can always adjust the dampers to compensate for the roll you are correcting. If anything I think that the D's would feel like they promote a bit more understeer just because the fronts a bit stiffer than the rear(compared to the X's)

[orion::S14]

8/6 is PLENTY for roll resistance for street tires.

Probably too stiff for street tires unless they are good and sticky, and on a smooth surface.

Are you planning on anti-roll bars, or not?

- Brian


- Brian

[sean350z]

well i have the nismo power brace up front with the stock front sway which i will be replacing the bushings...probably will not replace the stock unit

the rear is the stock SE bar (kinda small) so that might be replaced later if need be to control steering conditions.

i think i'll just the the function x...

[orion::S14]

FWIW, I run a "powerbrace", Whiteline front bar, and stock rear bar. Tein HE, with 8/6 rates.

My car was too tail happy with the Whiteline rear bar, so I took it off in favor of the stocker. It's perfectly balanced now (tiny hint of oversteer, *perfect*) with 25/40-17 Kumho MX's on all four.

- Brian

[RBS14]

Another factor affecting roll resistance is how low the car is. The lower the car is, the less roll resistance it will have. Just something to keep in mind when you are setting it all up.

[Jefferson]

Hmm I have Tein HE's (set to 10F 12R) , stock front sway, whiteline rear sway on the soft setting, and tension rods with 235-40-17. I can say my car is pretty nuetral right now, I like the way it is.

[RBS14]

10k Front and 12K rear? or you mean the other way around? I hope...

[sean350z]

probably damping settings...that'd be ultra weird for spring rates

thanks for you input guys, after i install the bushings in the front i'll install the coilovers and then get tires. was looking into kuhmo ecsta v700s 225/50 none staggered on stock SE wheels. i have a staggered setup on my Z33 and hate the steering qualitiess (it's more for looks than anything else).

most people just buy coilovers and be done with it, i want to do this right and not have to buy 5 different setups before everything is said and done. you're input is greatly appriciated and will ultimately save money which is a GOOD thing

[!Zar!]

There is no correct spring rate, it all depends on where you live, drive, participate in motor sports with.

If you drive mountain style roads, chances are higher that it will be bumpier and not as smooth as a race track. So under a circumstance like that then it would reuquire a softer spring rate.

But if you're autoXing then you might want something a little stiffer than a mountain setup.

For some reason some people think that body roll is bad. Yes too little of it numbs a car, but none will make a car far too unstable leading you to horrid under/oversteer.

I'm not going to tell you what to get, but zeal coils for what you want them for is overkill.

I suggest you buy something lower priced and spend your money on alignment and or other suspension parts.

10k Front and 12K rear? or you mean the other way around? I hope...
That's his dampening.

Don't know why he would want the front softer than the rear, but whatever...

[RBS14]

A GOOD set of dampers is never overkill. Get the best ones you can afford. I've taken rides in a car with Function D's and let me tell you.... They're INCREDIBLE. Zeal is top notch, if you can afford it, get them. Done.