went out for a couple of runs.

fully stock 05 MCS on a pretty perfectly flat surface, 16'' wheels, sunroof and girlfriend.

0-60: 6.89 s.
1/4M: 15.34 @ 92MPH

better then what I was expecting...

 

im looking into getting one of thoes things. Tell me what you think of it (i.e. accuracy)

 

I'm actually very impressed up to now. When you put it on the realtime G-display mode, you really get the feeling that it's VERY precise.

I will need to go to the track to compare 1/4 mile times.

 

Sounds awsome Which one did you get? The drag one or the track racing one?

 

ive heard of those things being as far off as 2 seconds on the 1/4 miles times (yours looks about right)

i wouldnt trust it and most people you talk to about racing times will laugh at you if you base what your car will run off a gtech.

 

It is very nice because of its rev reader and gometer. It makes for some quite useful information.

 

They are not so much accurate as they are consistant. Which is great for testing mods and driving techniques. A few trips down the 1320 will be a good way to test its accuracy and get a baseline.
I had one of these units for awhile and it is a useful tool for modders.

 

Car and Driver did a review of the various models a couple months ago:

http://www.caranddriver.com/article....&page_number=1

Dave.

 

IT looks like the G-Tech got a very nice score. IT was only beat in accuracy by the $1000 one...

 

A good accelerometer could map your position vs time to the inch by the millisecond. Two of the biggest issues are timing of the launch (how you simulate the christmass tree), and how good the parts inside the G-Tech are. Nology has a box, I haven't seen it, but the display that's on the web looks cool. Map the track in 3-D!.

If it's repeatable, it's good enough for tuning. Maybe not "certified", but if it can tell when things are getting better or worse, that's pretty usefull.

Matt

 

I think the "taking off" detection is pretty amaizing. If you hold it in your hands steady and tell it you will make a new run, you push it max 1 inch and the timer starts.

I dont see why that is not accurate???

 

This is a little Off topic, but here it is anyways:

I got the chance to test another car...

a bone stock 2000 Mercedes E430, man that thing goes!

1/4 mile in 14.92
0-60 in 6.68

the MCS gets a beating!

 

A friend is lending me his G-Tech later this week. I'll post results for an '05 MCS/JCW with sunroof, LSD, and 17" S-Lites.

I haven't seen any times posted for this combo.

Rawhyde

 

while that does give a "best possible" number, it won't give the same number as a drag strip because of reaction time issues.....

So it's usefull in that it's pretty accurate (from the reviews). and that it's repeatable. So you can learn a lot from what it says. But it's not identical to a drag strip.

don't get me wrong, I like data, data, data, and I'll get a first hand look when I get my hands on one, which should be Thursday.....

Matt

 

First off, it's a pretty slick little unit. First the bad, then the good.

Bad 1) The display looks like crap with polarized glasses. This is true for a lot of LCDs but I like polarized sun-glasses, so it's a bit dissapointing, but not unexpected.

Bad 2) The RPM pick up is by AC ripple put onto the 12 volt line. The alternator needs to be doing something for it to pick up a good signal. This means that you have to have a load on the electrical for the calibration, and for runs where you want to plot something vs RPM. Not a big deal for relative improvements, but a big deal for absoulte power measurements.

The good.....

1) This is really number 2 all over again! Because there's nothing but the power to hook up, it's a snap to install.

2) It's really good at what it does. I was doing 1/4 times and 0-60s within minutes of RPM calibration.

Some other comments.....
To get the most out of it, you have to do ALL the advanced calibrations. I"m impatient and haven't done them all yet. But it can take into account most things.....

Use impressions. My clutch is toast. I couldn't get a 0-60 foot times under 2.5 sec if my life depended on it. I'm not surprised, as I drive hard and I have over 57k miles on the car. I was just hoping to have those new clutch neck snapping engagments with the DSC off....

So I did a few mushy clutch runs, and go 0-60 times from 6.9 to 7.1 sec. I"m sure there's at least 3/10ths to loose with better launches. But if I keep doing this all day, I'll need the clutch tomorrow..... For commuting and road coarse work, it should last a while longer......

My HP numbers were redicoulously low. 140 or so. I have some calibrations to do I guess..... With more use, I'll eventually post a review. I'm such a newbie with it that it wouldn't be fair to G-Tech......

One other point. there are cars that fail the RPM pick up. You can still do HP and Torque vs time, but not vs RPM. There are a bunch of pissed off people on the GTech forums.... But it works for the Mini, so far.....

Matt

 

A slipping clutch will show less HP on the G-Tech. Keep this in mind.

 

I have the big Vericom and it is a PITA to set up before each run.

As for the old precision vs. accuracy argument: repeatability is all you need to see if a mod is helping or not.

 

I'm finding the G-TEch is a good little system. There are issues (soon to be fixed) on RPM pick-up, but I find the location and ambient have more to do with times than the unit itself.

It has provisions for early or late staging, standard and pro christmass tree simulation, roll-out etc.

But I don't have a drag-strip, much less a level 1/4 mile shot where I can really air it out... So I'm finding locations where I can do repeatable, legal runs, and the repeatability is amazing.

No matter what though, the things uses your motion as a trigger, and drag strips use a light beam. All the set-up will get them close, but not exactly the same.....

And the clutch only slips on take-up. It's not so shot that it's a mechanica "torque converter". At least not yet!

Matt

 

I had to run a wire directly from the battery. I used the emergency + bat jump location on the side of the air cleaner box (Cooper S) in the front. That location will give a good pickup without having to turn on any electrical accessories to up the current draw. I used a 12 volt accessory socket from Radioshack (with fuse).

 

the reason I say that is that the GTech gets it's AC ripple from the alternator. The Alternator is "turned on" via an output wire from the ECU. If it's not needed (maybe at WOT as well) the alternator is "turned off". So no source of AC ripple.

Also, batteries are very low impedance items. So they should be able to dump what current is needed to supress the AC, as long as it's not too fast... Batteries are governed by chemical reaction times (pretty fast) and molecular diffusion (not so fast).....

Let me know if this is a permanant fix. Right now, I only get occational RPM drop outs. I have a fix in mind that works in all situations, but I don't wanna build it if I don't have to!

Matt

 

Just connect directly to that battery jumper point. I believe the problem is that some how the other common Bat+ pickup points supply filtered?? power. I tried a few other locations like the big + side on the engine fuse box, but no luck. I helped Onasled run the wire for his G-Tech at the last pully party in RI (Sept 04). Worked for him too! You need the RPM to give you some cool graphs of your speed / time and distance with shift points!

 

Dr.

A drag strip does use a light beam to trigger the timers but the car must roll out of the beam for it to start. If you shallow stage, just light the second stage, you will need to roll futher before the wheel passes the start beam.

If you deep stage, the first yellow stage light goes out, you have rolled the car futher down the track. These two technics affect the reaction time and also the 60 ft time.

A deep stage might show a better reaction time but slower 60 ft time as a shallow stage allows you to get a "run" at the start before the wheel fully passes the start beam, kind of a running start.

Either of these staging scenarios can change the overall 1/4 mile times depending on how your car reacts. Very important for racing but not so important for tuning.

It sounds like the GTech might give a more accurate 1/4 time since it eliminates the staging variables. But it doesn't replace a real 1/4 mile race:smile:

It sounds like it's best features are the g-forces (lateral and braking) and 0 to 60 times. It sounds like it would be great for tuning the car and driver for road course track days.

 

i have always looked into getting one of these and from what i have herd they are sweet! have you tried out the skid pad lateral g
s yet?

 

What do you use to turn it on and off? I'm on a switched fuse now.....

Sanddan, all you say is correct. In reading deeper into the G-Tech manual, I thing the root of the errors is the pitch approximation, witch describes the mount of lean the car generates under acceleration and braking..... But it should get very, very close. The other issue is that it's hard to find a place like a dragstrip anywhere other than a dragstrip. I've found a couple of spots to do legal 0-60s, and they are repeatable, but very, very different times and powers. I'm sure the settings can be tweaked with trial and error to get the two reading the same. Call it an empirical calibration!

Matt

 

Dr O,

There was a really good article on the G-Tech in the July issue of HotRod magazine that you might like to check out.

They did a series of 1/8 mile runs at a real drag strip and compared the G-Tech times with the drag strip times for the same runs. After tweaking the settings they saw ET's within a tenth of each other. This was with the RR version G-Tech.

If you want, I can scan the article and e-mail it to you. They also raved about the software that was included.

This might have to be this years Christmas present.