You don't have to enter vehicle weight for 1/4 mile or 0-100 times, only for power calculations. You just have to plug it in, stick it on the windscreen and make sure it is straight and level, and variations in its orientation will effect the readings.

mine pulled 3 go's 15.3-15.02 & 16.1 all top speeds were between 86-96mph
wheel spinning in 1st killed th slowest 1

yeh in th gtech manual it tells u the tolerances...

and also to take a heap of runs and average them

that was the best of 3 runs.. still no where near what I run at the drags (last time I ran was 13.9)

maybe that was a dodgy GTech

Yeah it could be a pretty average G-tech, one of the guys down here has the G-tech showing something like 12.8 1/4 mile time on a relatively stock V8 hehe. Also another factor I have found is that harsh shifts, in particular in manual's can sometimes throw the G-tech out a bit. So far my G-tech seems to be pretty accurate but the main thing is that it is consistant.

I have learned more about this G-Tech, and yes it is an extremely accurate way of measuring "true" performance
these tolerances are all +/-
0-60mph- 0.1 sec
60-0 braking distance- 2 feet
1/4 mile E.T. - 0.1 sec
1/4 mile speed- 1mph
horsepower -3hp
instant G force- .002G
cont. G force- .002G
NOTE all of these figures are only accurate if you are on level ground, for example if you ran the 1/4 up hill it will simulate more G's ,therefore more power/quicker E.T. Try going down hill and you will change the horizontal levels meaning you will have to basicly lift the wheels off the ground to get results as it measures from level ground.
I have also found a way to get close HP figures from a wild engine that doesn't like traction.
Just take off easy in 1st enough to get the unit started, short shift 2nd and take it easy as spinning the wheels will f**k the figures ,wait till you are about 4000rpm in 2nd or 3rd (depending how much it takes to not beak traction) ,then hammer it. it does take a few practices but you will work out when it all gets to the ground.
aero drag will rob you a bit, but lets face it ,it is what the car does when doing a run so
"BE SURE YOU TEST ON LEVEL GROUND!"
PS I got the falc down to 14.9 after a bit of playing round! still pretty s**t hey

OK... so all this talk of GTech's got me going.... so I bought one on ebay for $50.

Hopefull will arrive next week so I can have a bit of a play.


KS

I swear by it now, I have actually increased my HP an 0-100km/h,and not just by tenths of a sec , from171hp to peaking @255 now ,but I found that tuning a little less top end and more mid range my 0-100 went from8.2 sec (spinning) to 7.8- 7.4 -6.4sec and I found this extra by dropping my fuel pressure down to 34psi?, something I would have gone the other way if I didn't have evidence of an increase.
Another tip if you can't find a realy level road, always test at the same spot ,figures won't be perfect but you will see gains or losses. I gotta find a new spot now cos the locals are starting to look out their windows when they hear me pull up in the middle of the road.
I only take off near houses ,not speed ,the road is 800m long past the bush.
kenny