[GTP owner]

Originally Posted by SpoolMan

Which tracks measures mph before the 400 meter finish?


The time on a drag strip starts soon as the car moves past the 2nd staging beams, you stage on the line soon as you put your foot on the gas it starts recording.

Drag strip more reputable in my books with owner racing there own cars which is the true measurement of 1/4 mile and has been for 50 plus years..

Keep it simple post your times and then post the reference either magazine or the real world of a drag strip.

Our track here in tas measures the speed just before - the beam is 66 feet before the finish line, then the next is the actual finish beam. The speed is measured by the time it takes to pass between the beams, meaning it is the speed before the finish line, not actually at the finish line. This is true some of the larger tracks too (I just had a look at willowbanks details and it is the same)

As for the roll out on the start. There are 2 staging beams (top and second from the top orange lights on the xmas tree). The timing starts when you trip a 3rd beam, which is about 30cm in front of the second staging beam. Therefore the vehicle is moving by the time it breaks the timing light. In a high hp car, it can already be travelling at 6 to 8km/h by the time it trips the beam. I saw an example using a porsche 911 turbo that was demonstarting the differences in measurement.

So which is more accurate? Like i said - they give different times and speeds. The vbox shows a slower time but higher terminal speed. The drag strip the opposite.

The other problem i have is there are a few standard cars that are not quite so standard....if you get my drift.

My times at Tas dragway in standard cars
EL xr8 series 2 14.9sec at 99mph
BF Series 2 auto xr6t 13.8sec at 166km/h
BA GTP series 1 manual 13.9sec at 166km/h