i just ordered one from Amazon.com for $208. how accurate is it? has anyone compared it to other units?

 

They're okay. Elevations change their readings. I had this one, I also had another GTtimer and now I have the best one - Racelogic. The racelogic uses GPS instead of G forces and is by far the most consistent one. I've compared it to actual 1/4 mile tracks and it is within .5 mph on the trap speed and the ET is dead on! Using the Racelogic, my best 0-60 is 4.2 seconds with no rolling start (no 1 foot rollout).

 

The VBOX Performance Meter looks like the real deal!

 

Yeah, the racelogic is the VBOX. Much better - but it's 495$ or so. But you can keep track of your whole day on a chip and download it onto your computer if needed.

 

got my gtechpro today. setup was easy, but the rpm thing is a bit off.
i did 15 runs in both directions on a stretch of highway. ambien temp was 48 degrees F and humidity was ~ 75%. my car has lost 80lbs and i ran with 1/4 tank. so "curb weight" should be around 3600 lbs. best 0-60 was 4.34 sec. worst was 4.9 sec. there was definitely a good correlation between good times and good launches. i am not a drag racer and perfect launch is definitely hard for me. after several tries, i got a little better and i could easily achieve ~ 4.5 sec. i have the bridgestone tires with 7000 miles which do not have enough grip for this car. i lost grip with every launch, with better tires and technique, i believe 4.2 sec. should not be too hard, at least as measured by Gtechpro. i did 1/3 of the runs with full auto and sports on, the rest with manual and sports on. i didn't try manual with vsd off since i had trouble launching with vsd on. maybe i will try that in the near future.

overall, i am happy with this toy. definitely useful to assess improvements with mods or techniques.

 

How does it compare to Dynolicious for the iPhone?

http://www.dynolicious.com/