Review: KGMM S21 SuperSports S13

[LanceS13]

I said I'd do a reveiw after the first autox with them, so here goes...
The car setup was KYB AGX 4/4-f 4/8-r, whiteline bars 2/3-f 2/2-r, and of course the S21 springs 258lb/in-f 213lb/in-r.  Tires are the infamous sub-par Kuhmo 712's, which seem to be even more subpar when the track surface was probably in the low 50's (especially when the tires are old and hard to begin with).  Braking and accelerating were nothing but frantic searches for traction.  Lateral grip was about as good as could be expected, though...but anyway, this is a spring review, not tires.
When I installed the ProKits last year, the difference from stock seemed night and day.  There is an equal difference between the ProKits and the S21's.  The S21's have more rear spring bias, so with the rear bar on full stiff, steady state oversteer was almost always present.  I was hoping for this though.  That means I can take the rear bar down a notch to give me more traction on the inside rear tire to get out of the corner quicker, and let the springs keep the car neutral while turning.  
I never hit the bump stops, but since it was cold, I probably wasn't pulling as many lateral g's as usual.  It is yet to be seen if stickier tires or warmer surfaces will cause a bump stop problem.  
As I said, handling was mainly oversteer (but some rear bar tinkering should bring it back to neutral).  Body roll is minimal.  Despite the oversteer, the car is very controllable and predictable.  Oversteer onset is gradual enough for the experienced driver to catch it (I managed a couple of nice accidental drifts...and no spins).  I suspect with the softer rear bar, oversteer will still be fairly easily induced and just as controllable...just not as apparant.
The springs are on the verge of being non-streetable.  I can take it fine, but several not-so-performance-oriented passengers have said my car rides like a log wagon.  On smooth roads, you'd think it has the stock springs, but the first bump will quickly remind you of the almost doubled springrates.  Ride height can also be a problem when crossing gutters and such.  Ground to fender measurements (with 225/45/16 tires) are: 25.125"fr, 25"fl, 25"rr, 25"rl.  That's with a 12" sub in back, spare/jack in place, 1/2 tank of gas, no washer fluid, no driver.  Stock heights per FSM are, I believe, 27.32"f and 26.38"r with tires that are about 0.2" taller than mine.  This means there's a slight rake which may account for some of the oversteer.
Bottom line...good springs. &nbsp;With different bar setups, they should be great for both autox/road racing and drifting events. &nbsp;These are the stiffest springs available for the 240SX to my knowledge and they're linear, not progressive. &nbsp;If you do a lot of competition events and can put up with the compromise in comfort, I think these springs coupled with some good adjustable shocks/struts are the next best thing to full coilovers. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

[nrcooled]

I am getting the exact same setup minus the roll bars (I have an SE) on the way. &nbsp;I can't wait to take her down to VIR in FEB. &nbsp;Good to hear that you like the setup. &nbsp;If you make anyfurther tweeks and really like them ::i.e. damping settings on the shocks:: &nbsp; Please give me a shout. &nbsp;

I will get a review up after my outing. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

[West]

Nice, KG/MM make badass stuff, where did you get them?

Also, what setting would be the stiffest rating on your whitline sway bar? I set mine to the first one, but im not sure if thats the stiffest. Thanks!

[LanceS13]

I got them from skrperformance.com. &nbsp;I think they were $298. &nbsp;Phone service was pretty good, but forget trying to email them.
The sway bar endlinks act kinda like the fulcrum of a lever. &nbsp;The further towards the end (rear) of the bar the endlink is, the more leverage it has and the less roll resistance the bar creates. &nbsp;Basically, the bar becomes stiffer as its effective length is shortened. &nbsp;Does that make sense?

Oh yeah, even with the lack of traction, I managed a distant second to a guy that's been autox'ing for thirty years and ahead of about 5 or 6 other guys my age. &nbsp;The other cars included the well-prepared and well-driven late '80s civic in first, a few later model civics and integras, maybe a cavalier?, and another S13.

[LanceS13]

And one more thing I forgot to mention: alignment.
Camber bolts on the front will easily correct the camber to -1.5deg. The factory adjustment in the rear only got me to -2.3deg. Either offset whiteline rear control arm bushings or adjustable rear upper control arms are in order. I'll probably go the more expensive but more versatile adjustable RUCA route when I can afford it...until then, I'll just rotate the tires religiously.