I'm thinking of getting one as there is not a dragway around here to test my times. How accurate are the measurements?

I could get an average of 15.6 @ 92 mph with a Stillen intake, Stillen muffler, and valvebody recalibration. If If it's really 92 mph, my car should be in the low 15's.

I haven't tried running with y pipe, CAI, vb, and muffler yet because I'm waiting to install the UR pulley first. I need a b pipe... :(

Forgot to mention, I didn't manually shift my car.

Okay, if you average the results
 

I had one for a couple of months and then I sold it. You can get results all over the place, especially if you don't zero it in exactly. (Especially with the HP readings) Another problem is finding level and straight road. My results were very good with a slight downhill. :) Some people like to report their best time through the G-Tech, which can never be reproduced at the track with good conditions. I think Y2KevSE's time is right on the money with his mods. I think he would do better at the track though.

G-Tech
 

My friend just got it last week, so we took my car out on Friday. With about a half tank of gas and me and him in the car, the best 0-60 i got was 6.86 sec. I'm sure if i worked more on the 1/4 mile i would definitely do low 15's.
i don't think it's 100% accurate, but if there is no track around, i think i'd get it. i had a lot of fun with that thing.
peace

the g-tech
 

takes the MPH reading at EXACTLY the end of the 1/4 mile. When you go to the track the MPH reading is the average of two laser beams at the end of the track that are set a few feet apart, so when a car passes through the 2nd beam, the car is going faster than the average speed through both beams. G-tech can only take the final reading, so your MPH reading will always be higher with the G-tech. so figure about 1-2 mph slower in an actual track. but the elapsed time should be about equal.

GTech is CONSISTENTLY inaccurate...so its not that bad...
it will CONSISTENTLY be off by 2/10ths quicker than actual and 4-5 mph faster than actual...
But its consistent...so thats the key...
Good tuning device.

PS: I've tested it against an actual track on numerous occasions at different temperatures...and its always off by about the same amount.

PPS: Anyone want one? I'll sell mine for $90.

I did the same tests and found the same consistent error, but to a lesser degree. In the 2 cars I tested it in, the ET was off about 0.1 sec and the mph read about 1.5-2 mph high. These tests were in high 14 second cars (Mustang GT and a VW GTi VR6). But, if the tests were made in faster/quicker cars (Ill bet Adam tested it in his old turbo Civic!), I could see the error growing, particulary in the mph reading.

exactly....
 

my tests were done with my civic...
when it was running 12's...
so it makes sense that the margin of error would increase...
BTW: the HP rating is waaaaaaaay off...
even with an accurate vehicle weight...

still think its a great tuning device...

Re: exactly....
 

For sure! In my old car, I put the GTech in HP mode (with very accurate weight numbers) and it was 80 HP off my Dynojet wheel power result! Dynojet said 301 hp, Gtech 220 hp. So, I had little faith in the power readings from that thing.