full throttle 100km/h, straight line, wet(but not raining)
.... bump ....
backside travels quite consequentially to the left. in a fraction of
second things back to normal (did not touch the steering at all -
figured it would be safer).
presumably, the S is perfectly balanced. presumably, it does not
need a spoiler of any sort, BUT it felt like I needed to get that
extra pressure on rear that very moment. any comments?

 

The bump in the road caused one tire (right rear) to lift and loose traction.

The S2000 has LSD and this will send more power to the tire (left rear) with traction.

The acceleration combined with the wet conditions caused the S2000 to "pull" to side with power (left rear).

The loose tire (right rear) makes contact with the road, gains traction and the LSD equalizes the power and everything is fine.

 

lesson- be really careful in the wet!
especially running s0-2s.
(other things to look out for:
changes in pavement- asphault to concrete; sand or gravel; bumps, etc.)-
and watch change and level of acceleration in corners-

 

many thanks yours, i did not know that Honda installed fancy gadgets on the S
(LSD, EPS,.. what have you). the physics behind what happened were clear,
that was not the problem...the question was - has anyone experienced the
need to put some extra weight on the back.
i was actually thinking of a known problem with the Audi TT, where they have
engineered the car in a way that the backside would travel in a big way at
certain speeds (unfortunately with casualties).

 

LSD = Limited Slip Differential, all S2000 have it.

I have had it occur under the conditions you described.

This doesn't happen that often, just under those conditions.

Weight in the rear would not help...if fact it would increase the chance of spinning. You would throw the 50/50 weight distribution off.

 

The Audi TT, because of its shape, produced aerodynamic lift at speed. That's why in the later models, a rear spoiler became standard. The S2000 does not have this issue nearly as bad. It is quite stable at high speed even without spoilers.

"brushman" has given a very competent explanation. I might also add that if the bump was big enough AND if you were driving on a high crown road with the car situated on the left portion, then this can also be attributed to gravity had the back end of your car left the ground.

 

Thank you

 

may i say thank you all...