AP1 vs AP2 Rear Subframe

[felixR]

After reading Pete's update here, I was curious to find out what the differences are between the AP1 and AP2 rear suspension.

From my research so far, the main difference is that the AP2's upper control arm mounting points are further apart than on the AP1. This means that the control arm bushings have less force acting on them perpendicular to their normal motion. They did this to minimize toe change in the rear under braking and acceleration. This is why the AP2 seems more forgiving and the AP1 seems sharper.

Are there any other differences?

What can you do to mitigate the AP1's rear bump steer issues?

[plAythiNG]

In basic I had read that under bumps, the rear suspension tends to toe out, and if that occurs midway through a corner, hence the snap oversteer. Most probably a reason to why many S2000 run some toe in to compensate, and prepare for the toe out mid corner!

[eskimo_firefighter]

You're both pretty much spot on.

There are a few ways to mitigate the rear bumpsteer issue.

1. Dial in more rear toe in with your wheel alignment. This is kind of a band aid fix but will help stablise the car.
2. Install a set of aftermarket rear toe arms.

I have done option 1 in my car so far and it is handling very well. I will be doing option 2 when I get a chance to measure up the S2000's rear bumpsteer with Tom, followed by an install of my J's Racing rear toe arms which we will also measure. I will update on my blog when this is all done, although this won't be done for at least another month.

[plAythiNG]

make sure you share on this thread, and your blog for maximum visibility!

Always found yours and Tom's posts insightful to say the least!

[eskimo_firefighter]

No worries will do, glad you find the updates insightful.

Just to add I don't think the bumpsteer issue is severe. The S2000 can be a twitchy car at the limit but it is manageable.

[eskimo_firefighter]

Can confirm rear bumpsteer kit helps with the AP1's rear bumpsteer issue.