Aw, thanks for the consolation, guys. :cry:
Here's how high I figure I must have revved the motor. Gear ratios for my "4k" transmission are: 1st, 3.45, 2nd, 2.12. When racing it I usually revv it until the revv limiter starts to limit fuel before shifting into the next gear, but also try to match the shift with a turn when possible, which I'm estimating input the RPM in 2nd at time of shift around 5000rpm or maybe a little higher, but probably not much higher than 5500rpm.
Going from 2.12 to 3.45 is a 63% gain in RPMs. So if I was at 5000rpm in 2nd gear, I would have revved it to 8150rpm in 1st, assuming the car didn't slow down at all. 5500rpm in 2nd would have put me at 8965rpm in 1st with no car slowdown. I have no doubt that the car slowed down some when downshifting, so maybe this range wasn't reached, but I'd say it's likely that it went over 7000rpm. I've heard that a solid lifter "JH" vw gas motor will start to float valves at about 7000rpm, so if the valvetrain is about the same on a 1.6l, that sounds right that I would have experienced valvefloat when I misshifted into 1st.
The experiment that will be interesting to get out of this experience, will be to see if the bottom end escaped unscathed (took the >7000rpm abuse) or not. As far as I can tell so far, no holes were punched in the side of the block, the engine still turns over, no oil was spilled out onto the track, etc, which is an encouraging sign for our motors. And remember this is with a totally-stock type prep of bottom end (no balancing or blueprinting to the bottom end, just think your basic economic "street-driver" type basic rebuild.)
I am considering slapping on a used "CY" head that my dad has, but will need to see what kind of condition it's in first. But then again, given this incident I may end up forfeiting this autocross season, as I'm getting married in September and am plenty busy with other things to do (grad school) - haven't decided yet...
Topic: Autocross race update (bench racing) (Read 9470 times)
