shock travel/velocity vs wheel spin

Does anyone measure and use shock velocity and or travel to limit wheel spin? Dependant on your data logger and electronic system I am wondering if this could be set up so that the computer could monitor such and start pulling out timing managing power as necessary?

For example if the shock separates at a high rate one could pull power out the ramp it back in.

Mike

I would think that if the shock velocity is to high, then you need a better shock. I know that may seem over simplified, but I think accurate.
You need to think about the ultimate goal, accelerating the car as fast as possible. Pulling power wont help that goal.

Dave Morgan wrote about this extensively a couple of decades ago. I remember he was stumped at some shock speeds when they logged a BB stick car with ladder bars. IIRC, the logger couldn't record it because the speed was so high. So he had to rethink some of what he wrote before he saw those number. Sort of like he had to rethink how to mount a 4 link lower bar.

What you want to do sounds the same as what Slew rate programs are designed to do already. You set the rate of acceleration curve, if for some reason the engine is accelerating quicker, timing is pulled to slow it back down to follow the programmed rate. That's the simplistic definition.

MSD 7761 ARC controller or the 7531 both have that functionality.

It is illegal in most classes so finding people with experience is difficult. Look to the fast heads up guys.

As Trendz said, Riding the dots isn't going to be the fastest way down the track, but it will prevent a bad run from becoming a terrible one.

Since you are only dealing with 2-4 inches of travel, slowing that down with timing might be a little too late. Maybe taking timing out with excessive rear wheel speed acceleration would be better. Or better yet, an ABS system with software that monitors wheel acceleration.

What happens first? Rear shock extending at a rapid rate or the tire beginning to spin?

A system that can track wheel speed from a non driven wheel and a drive wheel will probably be the most effective.

This is a cool video showing the capabilities of the MS3PRO EFI. Pretty cool to watch the computer pull timing based on the wheel speed differential.

https://youtu.be/FembJNagxOE

The firebird the video is from is no slouch, 8.50 car.

Shock movement occurs before the tire breaks traction.
Doug

I know theres alot of people that use liner lasers like the banner Q50,or some sort of string gauge to monitor shock and front end travel and use that data along with some sort of a rpm signal via the drive shaft or pinion,transmission yoke and pull timing to avoid pulling a big wheelie or tire spin.

Spot on! That's why I am thinking about a way to manage power using shock velocity rather than a wheel spin situation to manage power. One concern I have is bumps or depressions in the track surface. I guess one could filter that out with certain parameters and go from there.