The G-TECH Pro meter is supposed to have 1/10 sec +/- accuracy in 0-60 mph and 1/4 time
while trap speed has 1 mph +/- accuracy. According to my experience, G-Tech time measurements is a bit optmistic
than on the race track.
My observation is that the G-TECH is usually
0.1 ~ 0.3 sec and 5 ~ 6 mph faster than track time.
You can see the Real Track Times on a 1/4-Mile Drag Strip of my BMW 540i at
" THE CALIFORNIA SPEEDWAY QUARTER-MILE DRAG RACING EXPERIENCE "
I tested my 540i with the G-Tech Pro Device and it recorded my fastest run from 0~60mph was 3.87 seconds and my slowest was 4.61. I'm averaging 4.02 seconds in 8 runs.
My best time for the Quarter-Mile run was 12.48 seconds @ 119.79mph while I'm averaging 12.57 seconds @ 118.75 mph in 5 runs.