i have been messing with a friends g-tech...the older kind....and i was just wondering how accurate they are...or well how much i need to take off the reading to get a good idea of how i run...thanks

the gtech is very accurate against itself, just not real accurate against the real thing.

Basically they are good at telling you whether a mod worked or not

so as for the real thing...umm waaaay off?

Depends on too many variables to give you a firm answer generally a couple tenths off either way.

from what i hear, it is very accurate with 0-60, 1/4 mile, and g loads, BUT it is extremely wrong when it comes to guaging HP and TQ numbers. It is however an easy way to tell if mods improve HP. gtech will definitely notice and the HP/TQ numbers will change up or down but the precise gains are unknown unless you go to a dyno