Coilovers. GC vs Tein vs RS*R vs KW etc.

[GTM_Challenge]

My point is that the car oversteers from the factory. Changing stagger can alleviate this issue. That's all. I'm not saying that more front spring than rear is optimal, simply that I'm not going to pass judgement on a kit because the front spring rates are stiffer.

These $4k Ohlins we just got in have 6k springs at all 4 corners. Do they not perform well because the rear rates are the same as the fronts?

Softer rear springs just mean the car is easier to drive with a bias towards understeer.

*edit* while you are certainly right re: spring rates and motion ratio, who knows? Maybe I'll find I like a stiffer spring more in the front. Popular belief when the s2000 came out was that there needed to be more spring in the rear than the front. Almost all kits and lowering springs were sold with this mentailty. It wasn't until a few years later that they found out more spring up front works better. Has anyone even tried tracking with more spring up front than the rear?

[SubieNate]

In my first post on the subject I mentioned the RCE Yellows being the most rearward I think I'd like, and they're equal all around too.

I'm all for experimentation, but since the Subaru stock seems to tend towards understeer (As opposed to the FR-S) and it still has stiffer springs in the back than the front, albeit a much closer ratio, something tells me that going 2kg/mm in the opposite direction is going to do more harm than good.

Nathan

[GTM_Challenge]

Originally Posted by SubieNate

In my first post on the subject I mentioned the RCE Yellows being the most rearward I think I'd like, and they're equal all around too.

I'm all for experimentation, but since the Subaru stock seems to tend towards understeer (As opposed to the FR-S) and it still has stiffer springs in the back than the front, albeit a much closer ratio, something tells me that going 2kg/mm in the opposite direction is going to do more harm than good.

Nathan

I'm interested to find out. Soft spring up front makes me think of understeer in general (no matter the rear rates) as you overload the fronts under heavy braking on corner entry.

[GTM_Challenge]

First swap will be front and rear springs from the KW Clubsports. Stock is 340/400. Will swap to a 400/340 rear

The car in Cali on 10k/12k springs wouldn't happen to have a large front bar and no rear bar would it? :P

[CSG David]

Originally Posted by GTM_Challenge

First swap will be front and rear springs from the KW Clubsports. Stock is 340/400. Will swap to a 400/340 rear

The car in Cali on 10k/12k springs wouldn't happen to have a large front bar and no rear bar would it? :P

We still run the stock front and rear sway bars Austin. hehe

[GTM_Challenge]

Originally Posted by CSG David

We still run the stock front and rear sway bars Austin. hehe

Gotcha, thought he was talking about Robi's car.

[CSG David]

Originally Posted by GTM_Challenge

Gotcha, thought he was talking about Robi's car.

[SubieNate]

I don't have a clue what rates Robi's car runs. The CSG car was what I was referring to.

[FRS2NV]

The FRS Kit is actually at 6Kg front and rear which is the Sport model and the BR-Z kit which is soon to be released will be different at aaround 8kg and kg


A few HSD kits have been installed and the reponse have been good from what i was told

[Figo]

I am struggling between KW V3 and RS-R. It seems like KW is a better brand. The only problem is that KW does not come with top mount and not recommended to use one. I would like to go -2 f and -1 r camber. Camber bolt may not go as far as -2.

I DD most of the time and autox with my friends not frequently. Basically I have the same need as @Re~Mix. But I also drift sometimes with 225/40r18 on 18X8.5 +44 Square DD wheels. Iv heard that KW and RSR are comfortable.
But with one do you recommend to me?

Thank you.

Originally Posted by CSG Mike

I've personally driven on RS-R "Moto-Spec", KW V3, Tein SRCs, and will be testing the Eibach R2 in the near future. As of now, the Tein SRC is my choice (and the reason it is on our shop car).

[ZDan]

Originally Posted by D1cker

The S2000's usually have stiffer front springs, or the same springs front/rear but the motion ratio is similar in the front and back so the wheel rate is also similar (I don't know the motion ratios off hand)

Info I have is 0.70 front and 0.67 rear (post #11 here: http://www.s2ki.com/s2000/topic/3800...tios-of-the-s/ )
50/50 f/r weight distribution implies you want to be in the neighborhood of equal wheel rates front and rear.
For equal front/rear wheel rates, the rear springs should be (0.70/0.67)^2 = 1.09x the stiffness of the front springs. A little more rear stiffness might be desired to have both "settle" at the same time after an impact, or a little less rear stiffness might be desired for stability and ability to put power down on corner exit.

Equal spring rates on an S2000 will give 9% greater effective stiffness (wheel rate) up front. I don't think I'd go any softer on the rear spring rates than front.

The FRS has strut front suspension which has close to a 1:1 motion ratio. Therefore in the front of my car which has 10kg/mm springs the wheel rate is about 10kg/mm. The rear is multilink and has about a 0.75:1 motion ratio, which means my 12KG rear springs have a wheel rate of 9kg/mm. And some people who run the same rates front to rear would have a 25% softer rear wheel rate.

You have to multiply by the SQUARE of the motion ratio! 12kg springs with a 0.75 motion ratio gives a rear wheel rate of 12*(.75)^2 = 6.75, NOT 9kg/mm!

If you see a coilover with spring rates of 9/7 then the wheel rates are going to be 9 and 5.25 which shows that company doesn't really understand the car and hasn't put any development work in (save for the ad)

Again, it's actually less than that. 7kg/mm * (.75)^2 =
3.94 kg/mm at the wheel.

With 55/45 weight distribution on the FR-S, for equal front/rear frequencies you would want the front wheel rate to be in the neighborhood of 1.1x greater than rear wheel rate (ratio = sqrt(55/45)). With 9kg/mm fronts, if we *assume* 1:1 up front (not a given, btw), you'd want a rear wheel rate of about 8kg/mm, so rear spring rate should be 8/(.75)^2 = 14 kg/mm.

A front weight biased rwd car, however, probably needs a bit more front roll stiffness bias in order to maximize drive grip on the lighter-loaded rear wheels, but still, I wouldn't think you'd want anything more front-biased than having equal spring rates all around. Based on 1:1 and 0.75:1 motion ratios, that would still be pretty heavily biased to the front (9kg/9kg springs => 9kg/5kg wheel rates).
Have to wonder if the front motion ratio is more like 0.9:1...

[CSG Mike]

Originally Posted by Figo

I am struggling between KW V3 and RS-R. It seems like KW is a better brand. The only problem is that KW does not come with top mount and not recommended to use one. I would like to go -2 f and -1 r camber. Camber bolt may not go as far as -2.

I DD most of the time and autox with my friends not frequently. Basically I have the same need as @Re~Mix. But I also drift sometimes with 225/40r18 on 18X8.5 +44 Square DD wheels. Iv heard that KW and RSR are comfortable.
But with one do you recommend to me?

Thank you.

The KW is 2 way adjustable. If you're willing to learn how to adjust dampers, then KW all the way. Otherwise, just get the RS-R.

[ZDan]

Personally, I'd much rather have a top mount with camber adjustability than 2 damping knobs, as long as the damping is in the ballpark for the application and spring rate out of the box. Either way, decent dampers with a highly digressive curve are a MUST.

I honestly don't think I'd bother with coilovers that didn't provide camber adjustment up front, which this car *desperately* needs. I'd just get sportline springs and Konis, and crash bolts if I didn't want to spend the $3500+ for KW ClubSports or Ohlins DFV.

[7thgear]

Originally Posted by GTM_Challenge

My point is that the car oversteers from the factory.

no car, even a ferrari, will oversteer from factory

put it on a skidpad and the front will break before the rear


if you're talking about throttle/brake induced oversteer (a driver input), then that's a whole different matter.

if you can't adjust your foot, you adjust the springs, grip goes down, predictability goes up, confidence goes up, so you actually end up driving faster and your times drop.... and that's how trends start...


no one wants to drive a scary car