See here: http://www.gtechpro.com/ for info

AND

here: http://www.edmunds.com/news/innovati...7/article.html for a review.

A friend of mine has one, im gonna try it out this weekend.

 

Personally, I think it's good to measure gains from mods (differences between runs).... however, not necessarily the best way to measure your 1/4 mile. Anyway, below are some links. The second link looks best as it's a comparison....

http://www.acura-cl.com/forums/showt...ighlight=Gtech

http://www.acura-cl.com/forums/showt...ighlight=Gtech

 

you really have to get the weight correct to have accurate readings

 

I have one and it's really accurate if used correctly. If used incorrectly it is inaccurate

I've used it at the track and was always w/i a couple of 100ths of the track time.

 

Wow... is it really that accurate? I know it's advertised pretty accurate.. but advertising and real world performance are two different things.

Still.... most people would only believe slips over a G-Tech time

 

where can i buy GTECH?? the new one.. and how much should i expect to pay?

 

I have one and only played around with it a few times. I am about to get the OBX headers and plan on useing it for before and after testing.

 

I used it once, best time with my mods was 0-60 inn 5.9 secs.......previous runs were 6.4 and 6.7 seconds

 

g-techs are pretty good ... kinda difficult to find a good flat place to run depending on where you live...

 

I got the Tazzo(www.tazzo.com) , but I have'nt tested it at the track, it seems to function well.

 

I am looking for the next generation Gtech Competition...

This one: http://www.gtechpro.com/competition.html

 

That's the ticket... However, you might want to call Tesla, as the software is "evolving"...

Summit Racing is supposed to be the current vendor of choice for the units (this info may be out of date now…)


The previous units can have "problems" with accuracy if the car has a good deal of aero lift at the end of a 1/4-mile run (pitch). This generally accounts for overly optimistic end-of-run velocities (when compared to the strip's trap velocity).

The squat/lift, on take off, will also screw-up the reading of the older GTech (the amount of error can be very small or large depending on the springs, power, weight transfer, etc)


YMMV

 

Just for fun, you might want to see how well it does with some bumps in the road...

 

They are cool for getting approx results and having something to measure against.

 

Yup, if you take a minute to set it up correctly it works like a champ. Scalbert will back me up on this too

I agree, most ppl scoff at the gtech, but most of them have never used one either.

 

Well.... I've talked to the guys at GTECH, and it’s a good tool for what it does, but, it can give you some "errors" depending on the situation. It does a very good job if you lucky enough to have a mount that doesn't move around much (I've been lucky that way). Ask Scalbert about the 5-mph+ end-of-trap speed errors that he mentioned vs. small ET error he mentioned some time ago. I puzzled over this for a while and could account for the 2-3 MPH vs. trap speed, but couldn't "account" for the 5 MPH end-of-quarter-mile speeds that some people were getting (Scalbert mentioned this). It took a few more weeks to figure out what was going on; it turns out that depending on your configuration (springs, spoiler, etc), you can get a high read at the end of the run due to the uneven lift on the car (from front-to-rear). This is dependent on the velocity squared. Depending on what springs are in the CLS and addition or lack of a spoiler, the lift from front-rear lift can be cancelled-out or significant.

The other issue concerns "being a good GTECH 'helper'/’user’. You are probably pretty careful and use the same stretch of road (yes/no)? When doing this, the "repeatability" of the unit, based on my own experience is excellent (same temp, conditions, mods == very close times). However, once the car is on a slight grade and/or has bumps, the readings don't average out.

Sounds like I'm bashing it -- NO! I'm suggesting that it can work very well and has some rather good uses and the current unit will never work out as a 1/4-mile standard. Even the new one that is coming out really needs 3-accelerometers AND 3-coriollis force/angular rate sensors (similar to the yaw sensor in the Navi) to make sure that the errors from bumps, pitch, yaw, and other effects are totally corrected.


Rate sensor (1 of 3):



Accelerometers (1 of 3):

LINK: http://ccrma-www.stanford.edu/CCRMA/...00000000000000

 

i have posted quite a few times about my use of g tech
i always use it in the same location and try to do runs when weather conditions are similar

my car is not modded(k/n not a real mod)
so for me, it has been a great tool to improve my launch technique and to compare the different uses of our trans

i have been able to bring my 1/4 times(only g tech timed) down from 15.2 to a low of 14.5 quite a significant improvement
are they real numbers, NO, but they are great for comparitve purposes. knowing that the variables are tiny.
is it a good/great tool, yes

if you plan to mod, great way to check improvements

i have not even played with measuring g forces cause i really don't care

whole other world available for autox nuts
my .02

 

I have a brand new G-tech Pro, sitting in its unopened box, that I got free when I bought a full set of BFG KDWS tires for my SHO a while back (BFG was running a promotion last year). I was thinking of putting up on eBay, but never got around to it. I have no use for it.

Mike

 

Put it up for sale in the black market

 

At he track I used G-Tech and 1/4m ET was right on but trap speed was as Eric said at least 5mph fast. Summary, if you want to know what you're going to run in the 1/4 G-Tech will give good indication of actual ET capability but 0-60 and trap speed in 1/4 not accurate!

 

Yes, it is all about the set up and repeatable runs at the same location. This cannot be used on the open roads as a absolute number. But it can be used for comparision if run in similar conditions and at the same location.

In agreement with Mike, it was consistant at the track with ideal road conditions when talking about ETs. The trap speed was high but mostly repeatable.

That high trap speed still bugs me though... But again, on the road, it may not be accurate but it shoudl be repeatable when run at the same location.

BTW, I don't use their mount. I use a strap on the armrest to keep it from moving too much.

 

If you have a road with bumps, you will find that it goes nuts...

The aero lift (front-to-rear) for a given configuration is going to be constant. The pitch due to aero forces is significant and will give you a consistent high reading due to the 1-axis accelerometer. The 1-G (of gravity) * sin( tilt_from_V^2_forces) - fwd_accel * cos( titlt_from_V^2_forces) is pretty nasty when compared to the meager forward acceleration at the end of run.

Too bad the pictures of a particular CLS are not around anymore (or I just can't find it) -- the front of the car looked like it had a very large amount of front lift at the end of a 1/4 mile run.

The pitch due to the squat is one issue at the start of run -- this can have a large impact on the ET.

The pitch at the end of run (due to aero effects) will have a large impact on the velocity as computed by the 1-axis accelerometer...