Apex1.0

So I just picked up a low mile S2k. The car is in like new condition and a ball to drive. AP1's (especially early ones) seem to come with a reputation for being less forgiving at the limit. My understanding is there are two reasons for this:

1) Dynamic rear toe that was engineered into every AP1. Basically the rear suspension is setup to have bumpsteer.

2) Relatively stiff rear suspension tuning, biasing the handling to oversteer. My understanding is the 2000 has the stiffest rear suspsnsion tuning of an S.

First off, is the above true? Second if so, what changes can I make to counter act these to make my S for forgiving?

I am not sure how to deal with the toe change, with the exception of an alignment and good driving technique. I can however reduce the cars tendancy to oversteer by removing or disconnecting the rear sway bar. Has anyone tried this, does it help? Ultimetly will it make my S more forgiving? Overall I want to leave it close to stock, this is mostly a street car but I will do 2 or more HPDE a year.

Thanks,

duffman13

There are 2 real ways to go about this. The inexpensive answer is just to push the car until you learn the limit, and try to stay below it. The rear toe change in my experience with my old AP1 only got me in trouble if I really overloaded the suspension, which was rare for me even running RS-3s on the car and autocrossing. Throwing an AP2 rear sway on the car could help as well.

The more expensive answer is a combination of mods. First, a rear bump steer kit, which minimizes the toe change under load(you can safely almost zero out your rear toe with one). At the same time, you'll need 17" wheels to fit the BSK due to the length of one of the bolts, it'll contact 16" wheels under load. So that's as good of an excuse as any to find some OE AP2 wheels. This will give you wider rear tires as well, which will raise the rear limit for you.

If you do the 17" wheels first you might find that just having the extra rear tire is enough for your driving style, but granted at the same time that extra grip might be more likely to put you into the more dangerous area of the toe curve.

EDIT: I wanted to add a good alignment to the mix. Right off the bat, I'd go with OE toe specs and -1F -2R camber for something that's both streetable and fun in track settings.

ringo14

buy an eibach front bar, its adjustable so u can tune it to your preference .. its also not expensive ,will raise the cars overall limits and help give you what you're looking for

SlowTeg

I'd say run the car as is and see what you think about it. I rode in a local friend's '01 s2k for a few laps that's bone stock with some Dunlop Z2's and he was turning some solid lap times. He said the car is a little loose, but he seemed to be fine taming it, although he is a good driver. I can't comment about the reality of the AP1's having "snap oversteer, (or being difficult to control at the limit)" as I haven't driven one at a track myself, but I'm sure some folks likely just aren't used to it and perhaps it's not quite as bad as people say it is..? Loose is fast.

ringo14

good point, i would drive it as is then maybe add the front bar after some track time, if you feel the need

imstimpy

Many people consider the AP1 suspension design to be a GOOD thing in motorsports. If the car is new to you, then find a safe way to push it and learn what it can do first before changing it.

duffman13

If what I've read about the AP1 rear geometry is correct, once the suspension is heavily loaded, the toe angle shifts outward, causing a hard-to-recover oversteer situation, which was referred to as snap oversteer*. The thing is, to generate the loading levels on the rear suspension to cause this, most drivers would need to be on R-Comps. This is what the rear BSK corrects, as it prevents/minimizes the toe change, making it harder to lose mechanical rear grip in a turn .

*Even though real snap oversteer is when you're steering/oversteering one direction and the tires hook up in a manner which 'snaps' you into a spin in the other direction. You can get snap oversteer in a fast FWDcar as well, I've done it autocrossing my old one.

SlowTeg

Yes I've read quite a bit about this as well (I have an AP2). Considering the OP is only looking to do maybe 2 HPDE events a year, and the car is primarily a steet car, I just wonder whether it's really worth it to get a rear BSK (doesn't sound like he's gonna run R comps). I see many folks on this forum buying BSKs, and likely many don't even track the car.

I was just making the point that the car might be just fine as is. I think we often times "jump the gun" about modding things because on paper it'll be "better," myself included. Maybe the BSK is worth it as it makes things more forgiving at the limit..? I don't know.. or perhaps you adjust your driving w/ a little more countersteering at the limit..

Bottom line I'd say run the car stock first and cross the "issue" with the BSK down the road and whether you want to dial out some oversteer or not. My 2 cents.

duffman13

I just want to say I absolutely agree with you. Like I said above, I had an AP1(00) before my current AP2(04), and while it was definitely a bit looser, I never felt worried even when driving hard that the rear was actively trying to come out on me. That said, a wider wheels like going from AP1s to AP2s never hurt anybody.

FWIW I'm still tracking on a spare set of AP1 wheels I bought when I had the old car running stock class because I have a set of RS-3s that still had plenty of meat on them, and I've never really felt like I'm at a loss for rear grip.

Apex1.0

Great info thanks for the help.

So basically, with street tires the suspension wont be loaded enough to dip into the range of significant dynamic toe change? If I pull the rear sway bar, I will load the suspension more (because its softer), will that create more problems? Is that why no one advocates removing the rear bar?

What happens if I want to lower it? Will that induce more dynamic toe? Can I tune this out by changing hte static settings? What are the factory toe specs compared to the UK settings? What is more forgiving? I would think more toe is stable, but I am not sure.

Finally, will a set of factory AP2 wheels and tires bias traction to tthe rear more than my AP1 setup?