This is unrelated to your post, but I figured I might as well tell u this after reading your signature.

Shen PCBs don't have the black blob, you can just screw with the chip and do whatever it was you wanted to do to your TOMY. There is another clone I found, really cheap, wheels were crap and the tires looked like they were flat, blue PCB cover, but this also has the exposed chip. Not having seen too many clones in detail or up close before, I'm not sure who else has this nonblobbed design, but figured I'd share what info I could offer.

In response to your post, I don't think it would really be worth the time and effort to get an exact speed for your bit. A better, cheaper way would be to time it over a stretch of ground. Or if you just wanted the effect, setup a hot shoe camera flash near the finish line or something and have it go off at a key time.