I had just a few minutes to play with the GTech Pro 502 (GPS based) performance meter... it was a blast but I'm not convinced at how acurate these things are for acceleration numbers.

I only had the opportunity to make two runs... the first one, I roasted the tires and pulled off an embarassing 0-60 of 5.88, the second I launched fairly mildly and came in close to the published numbers at 4.82...which I was happy with...but it seems like a better launch would have been significantly quicker which shouldn't be possible on an essentially all stock car...so I'm not convinced.

Typically, what's the margin of error on these things? has anyone else messed around with one? How did you do?

 

Running on the street with less than optimal traction?

 

I use one and enjoy the hell out of it. Have the older model (G Tech Pro) but you will find youtube videos that shows they are within a 1/10th or better of actual quarter mile times. Did you set it up to your car? frontal measurement, weight, etc.. The highest it locked in as in satellites was 9, thats with driving around with it for 20 minutes prior to making a run. Bone stock I did some initial runs and here's what it read all within 30 minutes of each other (3.73) First launch was at 1,500rpms, 1700rpms, then 2000 rpms. All done walking the clutch out trying to learn where the friction point is on this car, shifting at redline

 

How does this thing work this is the first time ive seen this. Where does it plug in to

 

Can you program in a reaction time into it too? It seems that it could never be as accurate as a track timer though since the ET doesn't start until you break the ET timer light on your launch. Unless you can program in a roll out on it to mimic a RT?

 

plugs into the cigarette lighter. Basically you have to drive around and lock in as much satellites as possible Ive locked in at 9 most of the time. Ive had it installed in my truck at MIR for more than 100 ET slips, surprisingly accurate. You can find info here if its for you GL
http://www.gtechprosupport.com/support/Manuals.htm

 

Mine is a 2010 model, I dont believe I saw that as an option. You do have an option of shallow staging, 12" rolloff..etc. check out the site, they have a forum and support section