anyone have one of these, do they really work?

 

I have gotten a couple results from one, but never got a real 1/4 mile time to compare.

 

I have an early one. Very repeatable and reliable if you mount it according to instuctions and input an accurate car weight. I loaned it to a buddy that drag races a lot and he used it against the track timers. He said it was 1/10 second in the same direction off of track time on every run, but you have to remember that drag track time is measured a little differently - I think tracks measure at a time or top speed "bracket" at the 1/4 mile mark while the G-Tech hits it dead on. I could be a little fuzzy on this fact tho.... You would be wise to use it on two runs, one each way, to eliminate road / wind variations in the results. Very handy to evaluate changes you make.
Daffy

 

I've got a brandy new one sitting in the box 'cause the weathers to lousy to try it out,sorry.

 

Just got one today..still reading...
Re 1/10 sec...wonder if that has anything to do with staging car...G-tech mentioned something about this on their demo clip at their web site....

 

The older Gtech does not let you input "rollout." If you think about how the Gtech works, it senses your forward motion, so it starts timing you at the very instant your car starts moving forward. At the dragstrip, the timer starts only after you trip the light, so depending on where you stage, you could already be moving forward when the dragstrip timer starts. So you might produce a slightly faster time according to the dragstrip timer, because it is measuring your time between the start beam and the finish beam, but it lets you get a slight rolling start.

The Gtech gives you a mph figure that is your calculated speed at the end of 1/4 mile. The track measures your time between 2 beams at the end of the track (how far apart are they??) so it is actually giving you an average speed over the last X feet. If your car is still accelerating at the end of the 1/4 mile then your actual speed at the finish line will be faster than the track's reported speed.

A car set up for drag racing with 4.11 gears probably is done accelerating at the end of the 1/4, but I know mine is still accelerating as I shift into 4th gear not too far before the finish line.

 

I have an early version and have tested dozens of cars. I check peak HP. A sample of some of my readings follow:

69 HP '93 Kawasaki ZX-6
98 HP '01 Yamaha R6
135 HP '68 Impala 327 9.5 CR 327-275HP cam
142 HP '63 215-200 HP Buick Engine in a '61 Corvette
165 HP '63 327-300 HP Corvette stone stock (1 owner)
170 HP '69 350-300 HP Corvette believed stock
188 HP '02 Blazer rated 270 Net HP (2 different trucks)
192 HP '71 350 Olds Cutlass (rated 180 HP Net Rated) Inverted Air Cleaner Lid
272 HP '01 350-350 Net HP Corvette some modifications
320 HP '69 Very Hot 355CID small block Chevy in '69 Corvette
345 HP '69 427 L88 in '69 Corvette
412 HP '04 505 (Viper stock)

These were all established with actual measured weights.

 

I'm weighing the 69 at the local refuse site...they are letting me use their scales....just received the GTech Pro RR.....

 

I always wondered how they get engine RPM thru the cig lighter. Never made sense to me. Is it true there is no distributor connection?

 

This is from their user guide:

"Every vehicle has a unique electronic "RPM signature", the G-tech must learn the RPM signature at different RPM levels on your particular vehicle before it can measure and record RPM"S..."

Simple set-up procedure....just plug adapter into cig lighter..and follow set-up steps..(involves running engine)
Rich

Link: http://www.gtechpro.com/rr.html

 

I have the older model. I love it. I use it after every performance mod, especially the 0to60 measurement. Very accurate. I like that I can use it in all of my vehicles. The nearest 1/4 mile strip is 3 hours away.
Bee Jay

 

wow , more positive responses that i thought this thread would get, i always wondered how it knew the rpm's to.
it sounds like it's pretty accurate. and i think when one of the models came out, it got some best new product of the year award.
which one do you guys like better,the new one or the older one? personally i like the looks of the older one, gotta love a blue display

 

Check ebay. The older model is cheap.
Bee Jay

 

1978mayhem...
I'd think of how you want to use it first...then compare...I got the Pro RR cause of features my friends liked...I am going to pass it around to friends for checking data on our vettes...
Be sure to weigh your vette....

 

Yep, when you get it, your friends will offer to test it out for you. Get a library style sign out sheet, so you know where to go to get it back.
Bee Jay

 

I will certainly use it first..it came yesterday...going to dump this afternoon to get 69 weighed on their scales...freebee...
Rich

 

I'd like to know what your Corvette weighs in at.
Bee Jay

 

What if we don't have a ciggaret lighter?

 

I got a G-tech Pro for my son a 1 1/2 yaers ago and was able to upgrade to RR specs online. I use it all the time now for the laptime segment and course charting. Very cool. After I download it to my PC, I can compare my line and speeds in individual corners, overlay multiple lap traces and compare times. I love it.

Hans

 

I built a D cell battery pack that I use for motorcylcle testing. Those battery recharge packs would also work.