turbo8765

I would really like to know if others with BSK kits installed are getting movement towards toe out with suspension compression. The BSK kits are supposed to increase stability, but if you start with a modest amount of toe in and end up with net toe out under compression it seems as though you might get ridiculous oversteer.

Anyone??

Andrew Wojteczko

If you shorten your shim stack you will return closer to the original toe curve. So yes you would be able to get slight toe in vs slight toe out with slightly less shim stack height.

turbo8765

My arm came with three shims, one large and two small. The height of the single large shim is roughly equal to the two small shims combined.

Right now, I have the large shim above the joint and the two small shims below. Would you suggest that I try one small above, and the large+small below?

Thanks

Andrew Wojteczko

If no shim puts the ball center at the same height as the oe balljoint center location, then the small shim above should do the trick. You definitely want the rear to toe slightly in in bump as opposed to out for stability. If full spherical I usually set for 0 toe change over 2" bump/2" droop but you may need to machine some smaller shims to get it exact.
I measured the bumpsteer on my ap2 rear with the T1R kit and it worked out best with 1 shim above.

Andrew Wojteczko

Also at least with the ap2 matching the toe eccentric position to the camber eccentric position seemed to give the best results.

turbo8765

Tried all possible combinations with the stock shims tonight. I found that the single large shim+one small shim above, and one small shim below yielded the best result. Not really what I would've predicted, but the results were repeatable, time and time again.

With this configuration, there was no change in toe from 0-2" compression, and only about 0.009 toe in from 2-3"compression. The results under rebound were nearly identical.

I am very pleased with the results after taking the time to test and retest all the possible configurations.

BTW, I called the toe arm manufacturer to ask what I should lube the outer joint with and they said nothing. Also, I asked if dust shields were available and they said they were not needed.

Random1

That's a great idea for corner balancing on a stock setup.

I always "over" pre-loaded the bushings for stock setup to get the lowest ride height and reduce the effect of the rear bump (roll) steer (put rear toe link closer to level).

captain_pants

Nice work turbo8765! This kind of info is hard to come by. It sure explains why the rear end of the S2000 feels so 'squirrely' over big bumps like train tracks. You'd have 0.8" of total toe-in once bottomed out. Wow! Given uneven weight/traction from side to side it's going to walk around a fair bit.

Rob - I don't think it would make much difference for an S2000, mine was pretty close to perfect as is. But I could see it helping some other cars.

speedengineer

Thanks for the info, good to know!

For reference though, the front suspension on the RSX toes in ~3/8" per side per inch of compression. Given 3" of compression, that is 2.7 times as bad as the rear of the AP1.

DER MotorSports

Turbo8765 if you need some help with that M3 let us know - we can make them handle like nobody's business. Good job on measuring BS and setting the links properly. Suspect a lot of people are buying kits and not setting them properly, may be why so many failures.