spring rate help

[YellwMonky]

After searchign around a bit, i gave up and decided to just ask.

I'm going in to buy the k-sports coilovers they're having a GB for @ NICO. But I just have a question I was hoping you guys could help me out with. What is a good spring rate for me?

I drive an s13 coupe. It is my daily driver, but I don't care too much about the ride quality. I don't want my cd player to skip when driving over a cigarette butt, but a little harshness is fine. My biggest concern is choosing a spring rate that is best for "grip style" driving. I'm not into drifting like most 240sx owners. My biggest interest is taking this car to the track & tight turn mountain passes. The available spring rates are 3.5, 5, 7, 9, 11, 13, 15, 18, and 22 kg/mm. Can anyone help me out?

Thanks in advance.

[formeRiceR]

I have HKS hypermax I had 10/8, but that sucked ass...not good for daily driving.
I swapped them out for 6/5 and those are actually comfortably stiff. a lot more grip than the 10/8 setup.

[nightwalker]

5/3.5 best for street

[GlacierFreeze]

Hey YellwMonky, I ordered the recommended for the s14 which was 8/6 on the K-Sport group buy. I road shotgun in an s14 with Tein HEs (friend's car) which have the same spring rate (8/6) and it doesn't feel too bad (CDs did't skip hitting small-medium bumps). I'm sure I could have felt it more if I were driving but I'm sure it won't be too bad. I'd suggest the recommended for the s13, 7/5.

[Chernobyl]

9/7 all the way. It's like breast implants... they say you should go bigger than what you initially want because eventually you will not be as impressed as you once were. How's that for an analogy?

22 would be interesting. Might as well just weld your struts solid.

[YellwMonky]

Thanks for the input so far. Do you guys have track experience? I'm looking for the best setup for track most of all. So FormeRicer, you think a lower spring rate is better for grip?

[West]

Check this out to see what other spring rates are, I need to update this list but it will teach you how to convert kg/mm to lbs/in.

http://www.zilvia.net/faqs/archive/springrates.asp

[YellwMonky]

cool tahnks~!

but that still doesn't answer my quesetion. It doesn't show what spring rates are good for what. I guess my basic question is a higher spring rate always better?

[West]

Depends on what you using your car for...

From the spring rates they offer I would do the following.

Street = 7/5
Grip/Touge/AutoX = 9/7 (could be kinda harsh on street, depends on the dampners)
Full Race = 11/9

Anything greater then that is rediculious on such a lightweight car, unless you want a trailer queen.

Its to bad there isnt a 8/6 setup as that is the standard for most coilovers for our cars. Which would be fine for street and grip type racing.

Personally I would get the 7/5 and if your not satisfied get the 9/7 for a backup so you can swap when wanted.

Also.. I would suggest waiting a bit for the coilovers being offered by Works Yamaguchi. Im not convinced the K-Sport have a quality dampner. The works are going to be right around the cost of the K's, definitly worth it even if its a littel extra.

[pruto]

read this: http://www.pdm-racing.com/products/suspension.html

1) like i've found out, ride quality has a LOT to do with the coilover "system", how the dampers are, how dampering is matched with spring rate. etc. So 8k/6k feels different on different coilover set ups. I current have 9/7 on my N1 pros and it still feel like i'm riding on springs. Infact, i would venture to say my coilovers handle holes in the road much better and feels better in general cause its less bouncy. but bumps suck, on a messed up bumpy turn (like the one in front of my house) i actually can't go as fast as when i was on my shock/springs, it understeers. Of course most tracks aren't that f*cked up =).

2) it really depends on your driving style, you ask 10 different people whats optimum rate for grip and you probably get 10 different answers. Stiffer springs means less body roll, and feels more *predictable*. however, it also has disadvantages ala pdm article.

anyway, really, don't ask for what rate you should get. Read up about it, and make up your own mind. Funny thing, some people can't drive cars set up by someone else.

[AceInHole]

i'm running a 9/7 combo and it's pretty flat for autocross with no swaybars installed (that's right, NONE). This is with a decent amount of lateral G's with R-compound DOT tires ( 245 wide Victoracers).

I took my girlfriend for a ride and she really couldn't tell the difference between the 9/7 D2's (same thing as KSports I hear) and my old Sportline/ Koni/ AGX setup, since the D2's seem MUCH better damped.

[GlacierFreeze]

Just get the recommended 7/5 to be on the safe side. In the future if you find those to not be stiff enough for you then order a stiffer pair of springs for a measely $60-70. Put it this way, would you rather get them too stiff or a little too soft?

Experience? Read my previous post about 8/6 (stiff, but not toooo stiff).

[YellwMonky]

Yeah AceInHole, I saw your review of the D2's and they say they are identical (other than color). I just wasn't sure if you were purely drift or you do autocross/mountain type driving. Ace, when you say no sway bars, you still have the stock sways right?

GlacierFreeze: Thanks for the help. I think I'd rather go a little too stiff than a little too soft. Sounds like I may go 9/7. If it's too stiff, i could always go buy 5's.

West: Can you elaborate more on the Works Yamaguchi coils? I did a quick search but didn't fi nd much on it. What do you mean by a little extra? I'm thinking of splurgin already on the K Offices' cause of the great price. What makes you doubt the quality of the dampener?

[Dunkee]

I would get Tein Flex. I had HEs and while they do handle quite nice, ride quality is not. Higher spring rates eliminate roll but you can achieve the same thing w/ tight anti-sway bars and semi-stiff springs. You actually handle worse on turns on the street w/ stiff springs & shocks cause they jump on slight bumps which makes the car lose traction. I've took many turns super fast but on the parts which had unsmooth surface, I had to lay off the gas. One time I didn't and exited out side ways. IMHO, semi-stiff and tight sways are the way to go.