I´ve just made a couple of 1/4 mile runs with a G-Tech, it´s a little gadget that shows your 1/4 times and 0-60 Mph.
It is my only option since we don´t have any race tracks around here. :(
Is things like the G-Tech accurate?
Anyone tried it?

My results in the 1/4 mile are : 13,50 sec./109 mph.
0-60 mph : 5,18 sec.

I am a little disappointed with my 13,50, but it´s perhaps normal for a car with moderate mods like mine..??? :cry
The tires spun just a little so the act.handling did not activate.

So... I would really appreciate if somebody can look at my numbers and mods and say if it looks realistic or if there´s something wrong here... :blueangel:

 

Those are almost the exact time I got. I only tried it a couple of times, I think with practice I coud do better. I have a six speed and the launches are tough. Either bogged down or couldn't hook up. I hear they are supposed to be very accurate. Even if they aren't absolutly accurate, they should be good for relative numbers. You can tell if you are getting better, even if your numbers at a track would be different. It just goes to show, that it isn't all car that makes numbers, the driver is very important.

 

Yep, they are.

 

I would say within 20%, they usually don't give a quicker reading than the track. I think you would have a better time at the track, that would put you in the ball park.

 

It's accurate to within a tenth of a second and two mph. Unfortunatly for your times, the strip would show your car a bit slower. I'd guess around 13.6 @ 107. I've run mine down the track and found it to be very consistant. Good luck. :cheers:

 

WOW! That what i call some fast replies! :D :cheers:

But...are my car atleast an "average" fast C5 or should it be faster with my mods? :confused:
I have read on this forum that it can be a big difference between stock vettes, on dynos and in "real life"
I wonder if mine is one of the low-hp vettes.???

 

Your times look fine. I wouldn't worry about the power your car is making.

You mentioned that the tires spun a bit. The launch is the most important part of measuring acceleration and quarter mile
times. This little bit of spinning cost you at least a tenth or two right there.

Make sure that traction control is off. It will slow you down if it is on.

It takes lots of practice to get really good quarter mile times.

 

From my experiences, the E.T. is usually very accurate. The MPH tends to be on the high side though. Your times sound on par for your car. :cool:

 

Ok you asked for it!!! I will tell you how accurate they are.....

I have brought the G-tech with me to the drag strip on several different runs with all my cars. Here are my results!

1st with my Vette... A 99' Hardtop M6 with light mods..
The G-tech avg within 2 tenths of a sec. but was 5+ mph high every run.
for example.... G-tech said 12.48 at 118... actual was 12.62 at 112

Now with my Mustang it was off by more. Usually 4 tenths quicker and also 5+mph faster. For example.... G-tech said 11.88 at 122... actual was 12.21 at 116

With the Prowler it read quick too.. usually 4 tenths and 7+ mph
Ex.... G-tech 14.27 at 98...... actually 14.69 at 91

The girlfriends Trans Am Ram Air A4( stock!) was just 2-3 tenths but still 5+mph high.
Ex... G-tech 13.12 at 109... actual 13.39 at 104

There you have my research. In all cases it has generated quicker and faster times then were actually recorded at the track. For what it's worth I think it is amazing what it can do from just a plug in and stick on unit. The 0 to 60 times seem accurate to me... C5s best is 4.28.... to the Mustangs 3.98.... prowlers 6.02... T/As... 4.88

I wont tell you how many runs it took me to break the Mustang into the 3's! Lets just say way to many!


[Modified by C5 Frank, 6:23 PM 5/1/2002]

 

The reason the G-Tech shows higher MPH is due to it measuring final speed, not the last 60 feet the drag strip timers capture.

The G-Tech in our case is almost dead on with time and about 3-4 mph higher due to the way it measures final speed.

Great for testing mods and real impacts of changes.

:cheers:

 

I always thought that the G-Tech reasoning never accounted for the differences in trap speeds. The traps at the end of the 1/4 mile give the average speed over the last 66 feet. At the end of the track, most street cars are accelerating very slowly. A 3 MPH difference between the trap speeds and the car's actual speed at the line is enormous.

Think about it this way: How much speed do you think the car will pick up in the last 66 feet? Consider that the car is traveling more than 160 ft/s at 110 MPH (a plausible speed at the traps). So to pick up 3 MPH in 66 feet, we're talking accelerations of about 10 mph/second. (This doesn't even mention the fact that you would have to gain more than 3 MPH to net a 3 MPH gap between the G-tech time and the average speeds recorded by the traps.)

I use a Race Logic AP-22. Out of the box, it reports .15-.3 seconds slower than the timeslip. But I can calibrate the unit with a correction factor. The main advantage, however, is the ability to download the acceleration data and create results like this:



In continuous recording mode, the AP-22 will record rollout data (which is lost or completely unaccounted for by the G-Tech). The car's rollout can take as much as .4 second. I am changing the correction factor and going back to the track in two weeks.

If anyone is interested, I will start a new topic that goes over the AP-22 functions.


[Modified by Racer281, 7:41 PM 5/1/2002]

 

One last thing about the AP-22. Since I have detailed time, distance, speed and G numbers (logged every .01 second), I can calculate my trap speeds exactly like the drag strip timers.

The times in the graph were recorded this weekend. (And yes, I know I drove like an old lady. 12.9@112 with lots of wheel hop.) I will go back to get less embarassing times.


[Modified by Racer281, 7:40 PM 5/1/2002]

 

I would like to learn more about the Race Logic AP-22. I'll look for your post if you do one. I’ll search the web for it.

BTW, my G-tech gives pretty much the same data as earlier posts. If you can get good traction on the street, we have found it shows effects of mods pretty reliably. Like others, we do not take much trust in the speed. ET is pretty consistent with our local ¼ mile track.

 

I have one,and it works great. :yesnod:
Use it to check out new mods,and compare the old times. :D

 

I just found the AP-22 website (http://www.race-technology.com)

I have seen this before now that I see the site. It will be interesting to see your comments on how it functions, what particular features do you use the most, etc. I like electronic gizmo’s, even more if they help you!

Now that I have run my 3500 rpm Vigilante :cheers: for the first time last night (no traction with run flats, as expected along with 90 degree weather!), I would like to learn more about the effect of the higher stall TC on the run.

 

I have done some testing on the G-Tech using a fifth wheel with on-board telemitry equipment and it is not repeatable or reliable beyond 2 tenths of a second which is nowhere near accurate enoungh. In order to have times that are scientifically accurate you have to have one more specific digit measured in order to have a reading you can trust, i.e. if you want to measure tenths a second, your equipment must be capable to measuring hundredths of a second. Just my .02 from the engineering world.

Neil :flag


[Modified by cruzin', 9:35 AM 5/2/2002]

 

I don't have a G-Tech or similar device, but it would seem to me that most people who report small ET discrepancies versus their official track times are saying the G-Tech gives a quicker ET. This would make sense to me in the case of standard transmissions since the G-Tech will not measure the small periods of no acceleration during shifts. I can't think of a reason why discrepancies would occur with autos, except perhaps that cars do not stay perfectly level down the strip and I imagine the G-Tech would have trouble compensating for this at it's $140 price point. As the car tilts backs under acceleration, the G-Tech would be tilted slightly backwards, which may trick it into thinking it's undergoing more acceleration than it really is. If this is what's happening, it would also account for the higher trap speed readings the unit tends to give. Not knowing how the G-Tech is put together or how solidly it gets mounted, however, this is just a wild guess. :crazy:

-Pete

 

The E\T's were spot on with mine.The G-Tech WILL always give you a
higher trap speed though.I took mine to the strip and it was pefect as
far as the times go.
Highly recommended.
01GT
:cheers: :cheers:

 

How much does the AP-22 sell for? :D

 

I have used the G-tech many many times at the track.It was VERY accurate.It was off by no more than 1/10th of a second and most of the time it was off by 1/100th of a second....that is ACCURATE.The speed will be higher due to it gives the mph at the exact end of the 1/4 mile and the track gives an average of the last 66 feet.To get accurate results the unit must be setup correctly.....Straight,level and on tight.