I am thinking about purchasing a G-Tech pro Competition to measure 0-60 and 1/4 mile on the street.

Has anybody used this on a ZO6, if so what horsepower and torque numbers did you get.

 

Nope - but I am curious how accurate those things are!

 

Me too. Anyone use one? :lurk:

 

They are pretty accurate on the 0-60 and 1/4 et's. They will read several mph high on the trap speed.

Here are times I've gotten in various cars 0-60

01 z06 with ecsta mx tires 4.8
same car with victoracers 4.5
95 camaro with mods 5.0
95 camaro stock 5.7
04 silverado ss 6.4
68 firbird w/455 5.1
96 dodge 1500 5.2l 9.2
friends 88 m3 7.4
neighbors sti 5.1

Haven't tried the HP. It's hard to find a good place to do the 1/4 that is straight, level, and safe enuf to hit 110 + mph.

 

How do they work? With GPS?

 

I tried my GTech Pro (not competition) on my C4 while at the track and I found that it was consistent, but its numbers were always a few tenths quicker than my time slips. The GTech MPH was about 5 MPH higher than my time slips. Never tried it in my Z06.

It uses a 3-axis accelerometer.

 

I think they give you an idea, not an absolute. Gotta go to the track for that. :D

 

The HP is generally very pessimistic from my own experience. The acceleration and trap are pretty close. A friend of mine borrowed mine and found it to be within 0.1s in the 1/8th and 0.3s in the 1/4 mile and within about 3 mph trap of his actual track times on the same runs, it was always slightly optimistic, but a good tool nonetheless.

I typically get 0-60 in 4.8s to 4.9s on the MXs with 2.1 to 2.2s 60 fts. The G-Tech is very consistent and reasonable if you set it up and calibrate it for your car. It uses 3 accelerometers to measure acceleration including lateral(cornering) gs and braking. One of coolest things is how it maps time vs distance up to 4000 feet and time vs speed up to 300 mph ( :eek: ). Given a safe place and time you could time a standing 1/2 mile. Wouldn't that be interesting......

Someone on this board with a Z06 got 12.4s@119 mph on the G-Tech, not too far off from the sound of it. I will be verifying mine soon. I have done mid-high 11s at up to 133 mph so far on the MXs.




[Modified by BoostManiac, 9:55 AM 5/4/2004]

 

The PASS software that comes with the competition model is pretty neat. Here are some screen shots from the few runs I've done:

1/4 mile runs


HP runs


Fun to compare various runs and cars.



[Modified by Aaron71771, 9:52 PM 5/3/2004]

 

Yeah the PASS software is awesome. Looks like the ZR-1 really has long legs in 3rd gear, 120 mph! Your times look very reasonable and realistic.

 

How close is the HP to actual? The G-Tec measures at the crank right?

 

HP on the Gtech is "net" hp. Which is HP to the rear wheels minus wind and road resistence, so it will be quite a bit lower then a dyno run (which I still need to do to compare). Also - you really have to get your weight right or it will be way off, I try to figure the car weight, my weight and gas weight into the number to get correct results, but there is always a margin of error. I've got less then new tires so they just spin off the line; I was able to manage a 4.8sec 0-60mph run a few times when the tires were in close to new. And I am shifting a little late too, so room for improvement.

I was comparing my runs to some Z06 PASS runs and I noticed the Z06 was hitting 4th before the end of the 1/4, is this normal? The numbers and graphs were very close.


[Modified by Aaron71771, 12:23 PM 5/4/2004]

 

Whoa I just noticed something is seriously skewed with your trap speed on run #3, a trap of 119 mph from a stock or lightly modded ZR1? And compared to an earlier run from the same car at only 111 mph? I have noticed sometimes you will get a forward g reading on the "Drag Mode" screen even when you are sitting still, you have to just move forward slightly and come to a complete stop to let the G-Tech get its bearings and return to 0.0 gs, otherwise it will give you much faster times than you actually ran. That and your rollout calibration are tricky issues. The rollout compensation is what causes the difference between ET to speed compared to 0mph -xxx speed times.

For example, I was doing runs consistently in the 130-133 mph range, but on one of the runs I didn't realize that I needed to move forward and stop to set the g-meter to zero again. On that run I trapped 140 mph, which was impossible because that would have required redlining 4th gear even with my extended redline, which I did not do. On the other runs, the speed matched my rpm/speed calculations almost exactly, which have also been measured on the dyno, so I know they were legit.




[Modified by BoostManiac, 12:41 PM 5/4/2004]

 

Yes it is.

 

No doubt that the speed on that run is messed up, I have them sorted from slowest to fastest on the screen pic. I would guess I am somewhere in the middle of the two middle runs (red/green). More runs need to be done, on different "tracks".

good info, I'll have to check that out next time I do some runs.

 

i used the g tech( the original ) at the track and have been using it for years. The best thing about it is that youdont have to go to the track to see if theres improvements after doing mods.

At the track we hooked it up to my brothers 97 ss. Believe it or not.. every single trap was within .02 of a second. the mph was always off by 1.8 - 2.2 mph.

The problem with using the gtech on the street i find is that i can get huge variations in mph and et at different locations. so best bet is to use it at the same location all the time and itll help you a bunch.
:cheers:

 

Very true. The problem is finding a good "test track in Mexico" where you can get away with standing 1/4 mile runs! I will probably restrict myself to 0-60 on the street from now on considering how lucky I have been. I am going to start taking mine with me to the track quite a bit though............ :smash: