Just curious if the ABS/TCS/VDC go nuts when you dyno since the rear tires are moving and the fronts are stationary. The reason I'm asking is because I'm going to be running 2" shorter 15" drag radials at the track which means the rear tires will be spinning faster than the fronts as I go down the track.

 

Mine freaked out when I got my smog check. (ie dyno to 20mph)

 

You have to turn the VDC off before you dyno. Any experienced Dyno operator will know that. If he doesnt, run away, far, far away. The ABS is not affected. But whatever you do, DO NOT hit the brakes while on a dyno. It will royally hose things up.

 

It doesn't matter if you shut VDC off or not. You hit it right on the head though, if the front tires ARN'T moving and the back tires are your VDC lights will light up (slip and abs). The VDC system 'sees' the rear tires moving but not the front tires and assumes that that is impossible so it shuts itself down (each wheel has a dedicated speed sensor). The good news is that as soon as you start driving normally the lights shut off and you are back to normal.

its hard to say what will happen with 2" differnet tires. You may not have an issue at all. I DEFINATELY wouldn't drive with the VDC on. I would look into getting one of those VDC memory switches that that one guy sells on here....

 

I've had my on the dyno and dyna many of time and never experience a VDC light if it was shut off.

 

Hmm... Every time I've had mine on the dyno I've had the problem. But, like I said once you drive 100 feet and shut the car off and turn it back on everything is fine. I was there for every dyno and I made sure VDC was off. I'm sure if they would have pulled the car out and brought the keys to me I never would have known the lights came on. But, since I was standing right next to the car and I pull it out I noticed.