and look for Bump Steer Kit in Marketplace

 

Here's a link to the item in our store. There are volumes of material on it in the forum so you'll have to do a search for those threads.

http://marketplace.s2ki.com/s2ki/product.p...23&cat=0&page=1

 

interesting

 

[QUOTE=Ludedude,May 10 2005, 10:02 PM] Here's a link to the item in our store.

 

Hey, who stole our company employees manual?

 

Before I got my S, I'm already aware of the rear anti-bumpsteer kit sold in the marketplace. I've always had an impression (probably because I read it in some of the posts) that there's too much rear toe-in change on stock suspension compression and therefore results in snap-oversteer. Now that I have my S, what I've observed with bone-stock suspension is not exactly the same kind of behavior as described but still some funky rear toe change. I'll do some more testing and perhaps wait until I get some real tires and/or suspension and/or alignment revision before going for the anti-BSK.

 

I think I found what the problem was (or at least part of it).

So, my car indeed handled quite funky on the track (Pacific Raceways) last week. Whenever the car leaned enough in the corners (didn't even have to be near traction limit), I would have to countersteer to correct. This included the WOT 110-ish kink on the front straight. The high-speed kink requires very little steering wheel angle to initiate the turn-in but the countersteer after the body lean was bigger in magnitude (in the other direction of course) than the initial turn-in! After a few laps, I was thinking, "Damn! I thought my driving at Pacific was OK but these people driving stock S suspension here must be crazy!". A friend of mine who's fast at Pacific in his miata rode in my car and said he would consider my car undrivable and he couldn't understand why I didn't spin out that day. People saw me going through turn 9 felt the same. I kind of remembered somebody mentioned running more rear toe-in helped factory rear bumpsteer problem so I tried changing it on the track. I tried as extreme as 1/4" toe-in per side but didn't seem to help much if any.

After the track day, I took out the right rear spring/shocks and anti-rollbar end-links to take a closer look at the toe curve against suspension travel. Just as it seems, it's always toe-in as suspension compresses further than stock ride height. And the least toe-in occurs at some point shortly above stock ride-height. I also checked all subframe/suspension bolts to make sure they're tight and no bent in suspension/subframe parts. I then checked bushing/ball-joint/wheel-bearing sloppiness and everything turned out just fine.

I then rechecked alignment and sure enough I found my front alignments were off (heard clunking noise on big-G banked turns from the alignment cam bolts not being able to hold position well enough). I guess stock torque #s on that bolt aren't enough for big-G banked turns on the track? Besides the clunked cam bolts, the front toe seems to be way off for some unknown reason. It was more like 1/4" toe-in per side! I'm pretty sure it was from a mistake when I measured/adjusted my front toe initially. After each alignment change, I had rechecked front camber, rear camber, and rear toe, but I guess I didn't check front toe. And since Murphy's Law has always been at its best for me , the only thing I didn't checked was of course the one that would've failed. Anyways, this massive front toe perfectly explains why the countersteer-on-body-lean behvaior.

So, after setting correct front toe-in (I meant to run almost 0-toe and now I do indeed) and also very little rear-toe in (to try out), the car seems to behave much better now (but then I can't test situations like the 110-ish WOT kink of the front straight at Pacific). The car still seems to start rotating when WOT out of corners but that's more likely because of slip angle. I'll have to get some real tires before I can find out if that's indeed true. Hopefully, this will solve the mystery of my funky suspension behavior.

So long everybody. Thanks for your contribution to this thread.

 

people say the S is a phenomenal track car in stock form...

however, there is this problem...

...so confusing.

 

You have to have known parameters (alignment in this case) to decide whether something is good or bad. Once he realigned, handling returned to what it should be.

Put on crappy tires on one end and you'll be wondering, too...

 

I sure don't see the handling as a problem! I run good tires, I have a good alignment and I'm always working to be smoother. Just remember what one person may experience as a problem another person may not even experience due to a difference in driving style.