http://www.gtechpro.com/gtechprocomp_howitworks.html

If it is that easy to get an RPM sigal why are we screwing around with tapping into the ECU wireing and spending $$$ to get window switches modified? Is this as accurate as measureing from the Tach or a coil? Is this something new?

The new Gtech Pro Competition is a little pricy at $250 but it says it replaces a shift light so that would be $50 saved. If it has more than 1 RPM output perhaps it could control a VI and save you another $50. If the price comes down a little I will definatly be tempted.

There was one other thread on this but the question about the RPM function was not in the title and there where not many useful replies. http://forums.maxima.org/showthread....ight=Gtech+rpm

 

The thread title was supposed to be "New G-tech measures RPM through Cig lighter Voltage? Is it really that easy?". Perhaps a kindly Mod could fix it for me?

 

are you the thread title police?

 

For some reason I'm doubting that's how it works. Remember, it's a very generic device. It probably works upon movement (of shifts ect.).
-Cyrus

 

rightttt.....


basically the way I would think it works it this, when the engine is running it is "disturbing" the electrical system by creating an AC current, which is either 1) very small or 2) is normalized by the car, in any event, that AC current is on top of the 12V DC current, and the g-tech is sensetive enough that it can sense the AC current on top of the DC current. there is probably some correlation to the number of periods (of AC) to the RPM, which is similar to how the ABS works, and from that it gets it's rpm setting.

and for those of you who haven't tried this product, keep your unwanted opinion to yourself, because opinion such as "oh, I don't think it really works" is 1) stupid, 2) does not provide any new information. obviously the product has to work, otherwise they would not be as successful as they are right now, and they wouldn't even be able to develop the "G-TECH/Pro Performance Meter" w/out being successful with the first one

 

But would it create a small enough current that changes all the way through redline? For some reason I'm doubting that. I mean come on, the old one measures HP through a cigarette lighter. How perfect can it be? Just my opinion.
-Cyrus

 

you are kidding me, right?????? the signal AC signal is sitting on the DC the whole time, why would it matter if it's redline or not, as long as the instrumentation is sensetive enough to measure that, there is no problem

if you actually follow the first link in the original post you will see that HP IS NOT DETERMINED THROUGH THE CIG LIGHTER. it is determine through the acceleration sensor in the lighter. basically, if you've gone so far in a finite amount of time and you also know the distance, then there is a formula you can use and it tells you how much hp it would take to get 3000lb car this far in this amount of time.

original g-tech uses cig lighter only as a power outlet

 

I just don't see how either the device or the signal are precise enough to measure each increase in RPMs. Maybe I'm blind.
I know that, guess it came out wrong, I'm just saying it's a huge stress to measure hp through like that (the only tangible input is the cigarette lighter). And we all know ho inaccurate the hp figures are.
I know, but I just don't see how accurate measuring the RPMs through the DC strength can be. Maybe I'll just wait until somebody uses one and see what they say. Some G-Tech figures (1/4-mile) are right on the money, others (hp) aren't close.
-Cyrus

 

My buddy got one of the first ones i dont know i'm from ct if you all remember the whole buy 4 tires get a free gtech device at sears. At least the old one works by first entering the weight of your car with people etc.. then you set it to mes. hp it is motion sensor activated so as soon as you get ready to go you move a finger or something and it goes it mesures distance somehow i'm not sure but it seems to be very accurate it said my auto max with hybrid intake in all at 179hp, quater mile at 15.7 thats not to bad for a free toy. I'm lookin to buy the new one soon.

 

well, whether you see how it works or don't, it makes no difference, it works. whether you believe the planet earth revolves around the sun also makes no difference, but it does, etc... if you look at the actual computer chip it is extremely small, and that works fairly well at whatever speed you desire, it seems that you have a problem "seeing" things

if you take any kind of electrical lab, it would be fairly easy for you to "see" that it's really easy to sense a signal sitting on another signal, you have to have the right instrumentation.

whatever, I'm not going to reply to this anymore, I don't care if you see it or not, I don't care about your guessing how it works, if you don't like it, don't get it.

 

It's my thread, I screwed up the title. I was interested in how it was possible to read RPM through voltage changes, I wanted that in the title so anyone who knew something about it would open the thread.

Thanks for the replys, especially Vinipux. Is this new technology? Is this as accurate as tapping into the tach or coil wire? Does it cost more? Why don't shift lights and window swiches work this way? It seems way easier than looking for an RPM signal.

 

I wasn't trying to argue rather get an explination. Maybe I'll upgrade to the Comp and see how it work for myself.
-Cyrus

 

the tech is prob older then your parents either way it's pretty old, I don't know why people haven't done it earlier, I think most would like to have a dedicated rpm link to the computer and have the lighter for other things, why doesn't shift lights and window switches work this way? well, I think it's "easier" to do it that way, the wire is "right there", g-tech is using fancy equipment to extrapolate it, which is cool and everything but it takes time and R&D to do that

 

All i know is that this newer version is good. I saw it in action and its really nice. I am really considering on getting it for only 170.

Chris

 

$170! Please tell me where. I was going to get one for x-mas but I've only seen them for $250.

 

I have the older G-Tech and it's basically just an accelerometer (sp).
It measures G-Force variations. If it doesn't detect current changes as the rpms go up to the shift point, perhaps the change in forward g forces denotes enough for it to approximate. Just guessing.
As far as accuray goes, it's a great test and tune tool. We had 2 runs with the GiTech at the dragway this weekend and it was off by only .1 of a second each time. That's damn good for a cigarette lighter device. Primarily. though it's good to do a run , change something (add intake, whatever), do another run and see the relative difference rather than take the numbers at face value.

JMHO

 

Where did you find it for $170? It's very tempting at that price. The website says it works as a shift light, does it have an output or does it have something built in that lights up at a set RPM?

 

That's what I'm sayin!

 

Ok the price they gave me was $170 Sema special price. It was for like 5 orders of them i believe. I dont remember how many exactly but it wasnt that many. Now for the shift light all you do is plug it into your cig lighter and it reads signals from there. Thats all you need to plug in. Its pretty tight when your in the car and while its working. I will be getting 1 when some cash rolls by.

Chris