i was wondering how accurate the g-tech's hp rating was. also, how accurate the times are. i've heard they're of a tenths or 2, but which way? 2 tenths faster, or 2 tenths slower? just curious

 

They're usually .2 seconds faster than the actual 1/4 mile ET. Don't really know why...

I'm gonna guess it's because there's no "beam" to pass at the start or finish line.

Most cars have a 6-8" "rollout" from the start. That's when the car moves, but isn't actually being timed yet. The G-Tech times as soon as the weight is shifted to the rear of the car.

They're usually 2-3 mph faster than the 1/4 mile. This is because the drag strip averages your speed from two beams at the end of the track.

The beams are 60ft apart, and the time it takes you to get from one to the other is used to determine your speed.

In order to stay consistant, the computer they use adds the two together, then divides by two. The result is your "average" speed over the last 60 ft.

Just to give you an reminder of what an "average" is...

Add each number to get a total, then divide by how many numbers you added together ...

64 + 36 = 100
100 / 2 = 50

38 + 42 + 20 = 100
100 / 3 = 33.333

The G-Tech displays your speed RIGHT AT the end of the 1/4 mile. So of course it reads a little faster.

 

Any idea where the .2 faster comes in? I have taken a few readings with the G-tech. It seems really close to on the 60' and 0-60 as the moates software.

On the 1/4 on the G-tech I got 14.3 @ 99 mph. 60' 2.37 0-60 6.3 1/8 was 9.3.

I haven't done any 1/4 with the moates stuff, nor have I been to the track, but 14.3 (or 14.5 with the .2 correction) seems about right (mods in sig).

My hp readings seem way low ~185 rwhp (add 20% and you get 230 fwhp which is below stock).

Any comments?

 

You'll also need to factor in air resistance, and air density corrections.

Ron

 

running my pro compition model at the strip it was .1 to .15 slow to the strip and 3to4 mph faster.

mike

 

http://www.gtechprosupport.com/suppo...ch-Rollout.pdf

Found this on the gtech site...pretty good discussion of rollout. What do you guys use for rollout. Mine is currently set to 12", which might account for .2 (as seen in the pdf), since the Gtech doesn't start counting till you've moved 12 inches. That seems pretty far esp when you consider bad traction..

 

i tested my gtech at the 1/4 last time i went and it was accurate to the .01 of a second. It did say my trap speed was 3 mph fast then my true trap speed.