I own a G-tech accelerometer (the latest version), as a testing device. It is a consistant baseline i use for all my vehicle('s) mods. I store all my runs and document them. I know the ET's are more accurate than the dyno numbers, but has anyone tested a g-tech against a real life drag-strip??
I do all my test runs on a long flat backroad. I survey the conditions and take an average of 2 runs both ways. I also calibrate it before each session... I haven't tested it yet, but i think the g-tech is a little generous by .1 or .2 seconds against the lights....
Im liking the numbers im seeing

 

when i first got mine we ran it at a track was .1 to .2 off in the 1/8th that was with version 1.0. mph was 3 to 4 mph high

mike

 

Mine was terribly off. I ran like .6 better than the gtech said. Of course my exhaust makes the hole car vibrate when I get on it so I think that has something to do with it. I have had friends that say they were within .3 of there gtech times on the dragstrip though. Guess there is only one way for you to find out.

 

Doesn't the Gtech start counting the moment you launch? That might be what causes the miss calculations.

 

Yeah, the way it calculates is usually what throws it off. Also, for the dyno part to work you can't have any wheelspin and it would read higher if you do it in a lower gear.

Just take it with you when you go to the track and compare the slip to the gtech. Just remember it shows the instantaneous speed not the trap speed.

Laters.

 

what i like is the consistancy i get when i run on the same road. I can run it 4 times in a row with very little varience.....
I am going to test it against the real deal in a few weeks. I haven't made it to the track yet.
G-tech works great for testing mods and the difference they make.

 

G-tech Pro (newer one) does not start from the moment you launch...

http://www.gtechprosupport.com/support/

Scroll down as to why they don't match the track...you can set the rollout on the g-tech (based on staging).

For testing HP, you have to run different than the 1/4 mile..yep its in the manual.

I have one..its 0-60 times are dead even with the ones I get in the moates software....

 

I took mine to the track once just to see how accurate it was, I did 5 runs with it and this is what I got, this is with the older version.

Track-------------------GTech
14.48 at 96.7mph----14.36 at 101.7mph
14.65 at 96.5----------14.54 at 101.7
14.53 at 96.5----------14.46 at 101.5
14.61 at 96.3----------14.49 at 100.7
14.52 at 96.4----------14.39 at 101.4

A average of 0.12 seconds faster and 5mph more I would say.

 

i have a tazzo, you can actually use it during a run at the track and then go back and correct all teh increments. it is pretty accurate once you dial it in. with in a tenth.

later
tim

 

We tested my car w/ it one day w/ the PRO at the track and it was only off by about .1 or .15 each time. MPH was high, but that is b/c of the way that the meter measures the MPH differnetly from the track. Track takes a measurement from 10 feet before, and then at the finish, and depending on how fast you go between those two, your MPH are calculated. The Gtech is what you MPH is at the end approximately supposively.

The reason it is off sometimes by so much is b/c the gtech takes into consideration no wheel spin.

 

The track measures the time it takes from 66 feet before the finish line, to the finish line. MPH is calculated on the time it takes to break both beams. Many, many years ago the timers were 66 feet before and 66 feet after the finish (132 feet total)(1/4 mile is 1320). The last 66 feet was eliminated since racers are required to slow down after the 1/4 mile. Having to accellerate another 66 feet wasn't productive for the race.

There's no other way a track can take a true mph reading right at the finish line unless a radar gun was used for both lanes. It needs to do a time over distance calculation to determine MPH.

A G-tech is an accellerometer. Since it measures accelleration on a constant input, it can tell how long it takes to do a 1/4 mile and will give a MPH at the 1/4 miel point. G-tech will also do garbage in/garbage out. If proper numbers such as vehicle weight or gear ratios are not used then inaccurate readings will result.