A while back you guys helped me out with my high speed handling problem, and I promised to let you know if the additional rear toe and front caster helped. I had the car re-aligned about a week ago, and the turn-in is slower now, even on the street. I haven't had the car over 100 yet (the mines have been working overtime lately and my test road has been unavailable), but I'm sure you guys nailed the problem. The car is now as it should be at 100, and the difference is VERY noticable, so I'm sure it's going to be OK at higher speeds.

Sorry, I couldn't find the old thread to post an update so I had to start a new thread.

In summary, near zero toe at the back is a bad idea.

Thanks guys!

 

what are the before/after alignment settings..


google normally finds your thread if you put in the total website as the search boundary.

 

Is this thread what you're talking about?

https://www.s2ki.com/forums/index.php?showtopic=367188

Good to hear that your problem is fixed. Sometimes missing a simple bit can make a big difference. That's why I suggested on that thread to rule out suspension/alignment/tire problem first. My MY00 was quite unstable on the track on 2 different sets of tires. I was tempting to blame the factory bumpsteer problem until I put on a set of somewhat decent street tires. It makes so much of a difference that my lap times shoot up by almost 2 full seconds and are even respectable if that lap time was on R-compounds.

 

Yea, that's it.

 

The "before" settings were suppose to be UK specs, but my alignment man made a conversion error (or maybe he was just a bad day), and the car was inadvertently set up as follows:

Camber: LF = -1.0, RF = -1.0, LR = -2.0, RR = -2.0
Caster: LF = 6.4, RF = 6.4
Front Toe: LF = -0.01, RF = 0.01, Total = 0.0, Steer Ahead = -0.01
Rear Toe: LR = 0.03, RR = 0.01, Total = 0.04, Thrust Angle = 0.01

The car was a little hyper at very high speeds (130+) and I had totally overlooked the rear toe alignment error.

The alignment is now set as follows:

Camber: LF = -1.0, RF = -0.9, LR = -2.0, RR = -2.0
Caster: LF = 6.7, RF = 6.8
Front Toe: LF = 0.01, RF = -0.01, Total = -0.01, Steer Ahead = 0.01
Rear Toe: LR = 0.35, RR = 0.35, Total = 0.7, Thrust angle = 0.00

As I said above, the additional toe has made a noticable difference, even at lower speeds. I'm going to bookmark the thread this time, and when I get a chance to test at speed I'll post IF there are any problems. Otherwise, there is no need, because I'm as sure as I can be that we've solved the problem.

My thanks to all the guys here who pitched in to help. It turned out to be a simple problem, but it had me chasing my tail, and without all the help I might still be trying to sort it out. Thanks!

 

Hey are these the UK specs?

 

It is very close. The exact UK spec calls for:

Front Camber = -1.0 degree
Front Caster = 6-45/60 degrees, which converts to 6.75 degrees.
Front Toe = 0.0
Rear Camber = -2.0
Rear Toe = 20/60 of degree, which converts to 0.33 degrees (total toe = 0.66-0.67 degrees)

I use tire temperatures across the tread at autocrosses as a part of my tuning, and got even temps across the tread with the above setup plus an extra 1/2 degree of negative camber at the back (-2.5 degrees instead of -2.0), so I expect to see a little more heat on the outside of the tire now. I wouldn't look at the UK specs as ideal, but they seem to be a good starting point.

 

Is that a typo? More -ve camber should yield more heat on the inside.

 

No, it's not a typo, but apparently it's a little hard to follow.

I get even temps across the tread with -2.5 degrees negative camber, so with only -2.0 degrees the tire is more vertical and the outside will likely run a little hotter.

In other words, you are correct; More negative camber means more heat on the inside of the tire, but I now have less negative camber, so I expect to see less heat on the inside and more on the outside.

LOL, now I'm a little confused, so I hope I got it right.

 

I guess you meant -2.0 gave you more heat on the outside than -2.5 camber. That I can certainly understand. My first impression was that you meant to say the opposite.