Hi all, as per the title I'm planning to get coilovers soon, most likely Ohlins, and the Karcepts FSB. I'm trying to decide on spring rate and sway bar combo. I've got an '00 AP1 with stock suspension and 255 square. Currently I actually quite like the car even on stock springs and sway bars. I was really concerned that the car would be excessively twitchy or over steer happy per reading the internet however I've found the car fairly derivable and predictable after autocrossing it several times and some long drives on back roads. The rear end feels slightly loose however I find the trailing over steer predictable and I also have a little bit of on-throttle push; the attitude of the car is pretty controllable with the throttle. Alignment is as follows: camber F/R -2*/-3*, 0* toe front, and 0.2* total toe in rear. The only thing I don't like about the car is that the front is fairly lazy in the transitions during autocross, likely due to the lack of a stiff front sway bar. Other wise it feels good enough on back roads. But maybe it could be better with a stiffer front sway bar? I plan on getting offset camber joints and dialing the front camber to -3* as well and hopefully that takes care of the on-throttle push? But I digress.

I'm debating between keeping the factory Ohlins 10k/8k springs or upgrading the rear to 10k as well. I'm concerned that the 10k/8k stagger will be too understeer oriented for my tastes after a stiffer front sway bar. And to that extent I'm not sure which center spline to get, 0.120 vs 0.188 vs 0.250, for similar reasons to prior. Or if stiffer spring rates alone can fix the laziness in transitions? I've been told second hand from a friend that, even though his NB miata has overly stiff springs, it still feels lazy compared to the D street FRS with stiffer front sways that he competes in. Unfortunately I don't have enough seat time to have felt it out for myself. I've also noticed in the STR autocross prep thread that a lot of people run extremely front stiffness biased setups. I can only assume that this is mostly necessary as this is the trend however I can only wonder what difference in driving style necessitates this.

Thanks,
-Shift

 

I suspect the "laziness" you're feeling isn't a F/R spring rate issue per se. Rather, with the square 255s you're pushing the car well beyond its design envelope, i.e. it's rolling more than it ever would on the stock tires. Also, remember your shocks are 18 years old!

I'd guess that once the car's properly sprung/damped for the amount of grip you have, you'll find the extra front stiffness to be beneficial. But even if not, you can always swap the springs, right (i.e. 8k/10k)? In fact, why not buy an extra pair of springs or two? Maybe two 8k, four 10k, two 12k.

Cheers

P.S. One reason for the stiff front bars in autox is the AP1 rear bars cause exit-traction issues. To solve that, people use a soft (or no) rear bar, and combat the increased body roll with a stiff front. Then they address balance with tires, coil springs and aggressive damper settings.

 

I can tell you how the stiff front bar, soft rear bar, higher front than rear spring rate setup works at the track. You basically end up tossing the car into corners, the front will feel numb-ish or push a bit mid to late corner if you're carrying enough speed, and you compensate that by adding more throttle and earlier to tighten the line. It's very stable compared to some other S2000s I've driven and lets you get on the throttle very early. Maybe not for everyone, but it works for me.

My car has digressive / linear custom valved Penskes with 850lb / 600lb springs (15.2kg/mm / 10.7kg/mm), Karcepts STR .250 front bar one step off full stiff, and Karcepts rear bar on full soft. I stiffen the rear one step on both sides when I run certain tracks that need easier rotation.

Quite frankly, I bought the car set up as-is and it works so well I am hesitant to mess with it after having driven some other S2000s.