This afternoon my friend and I went out and were testing our cars 0-60. I am a little sceptical to the accuracy of the g-tech because it gave my max a reading of 6.97. But i also tested my Dad's 330i sport(auto) and it was giving readings of 6.60s all day and i think that is right on the money. Also my brother used it the other day andhis 2k SE with intake and Cattman y was running 6.50s without dumping the clutch. I just dont know about my car running under 7 with just intake and exhaust.

 

It should be very possible. Our cars are as fast as supercharged GTP's. And they do 0-60 in 6.6-6.7. I took one 0-110 by about 1-2 car lengths, and all i have is intake mods. I always drop the clutch when racing, i dont know how much of a difference that makes.

 

I have an Auto and i just ran it again and posted a 15.18 1/4 mile and a 6.81 0-60. I dont think my car is that fast, well see on tuesday when i go to the track.

 

was that sig pic taken in bayside? that building looks familiar

 

Does anybody know how the G-Tech works?

 

I think s/o mentioned this b4 .. when you're timing yourself at the track ... the time starts @ go / green light whether your car actually moves or not ...

with the g-tech ... it begins timing when the car commences forward motion ...

sorta makes sense 2 me ... but not always

 

I'm pretty sure that there's a lot of configuring to be done in order to get the G-Tech accurate. You need to program in road temp, barometric pressure, elevation. Stuff that needs to be REALLY accurate otherwise your times will be that much less accurate. Plus on regular streets, they're not level so balance is off and uphill/downhill makes a big difference. Like any computer system, garbage in garbage out. (That's the second time this week I used that phrase! No, you can't be like me!)

 

My understanding is like stated if you do not enter all the info you will have less than accurate stats. Also at the track the time does not start until you move green or not. which is why your RT does not affect your time.

Atleast that is my understanding.

 

RT DOES affect trap time. I saw a guy run what should have been like a 9.8 but he stalled at the line had a ~6 sec RT. His final time was in the high 15s. This was a competition and he was knocked out because of that run. When that light goes green, you better move your ***.

 

Dude there are so many wrong statements in this thread I don't know where to begin.

First of all, RT doesn't affect trap in normal racing. Just in professional and bracket racing. It doesn't start the clock until your car rolls past the line. That guy may have rolled a little bit when he stalled (thus starting the clock).

Also, the G-Tech does not need any settings to be more accurate except for the HP stats. As far as accelleration, and trap speed it's all relying on the movement of the car, the momentum, and the force. It's an accellometer, very accurate, and it doesn't need setting to guage things. It starts when it sense movement. Those things are so accurate that if you are at 0MPH and then roll you car .0001 MPH it would turn on and give you a 1/4 mile time of 3 months (if it supported that high).

 

Did I not say it was a competition? And no, he didn't roll because they actually listed his RT time and Trap time as what they should have been ~6 and ~9 respectively. Do you really think it was just joe shmoe in a 9 sec car? No, it was a pro racing a 300zx in a street class. And whether or not they start the clock at movement or green is a per track thing, because that equip is expensive to have and use. Most start at green. And do you own a G-Tech, because everybody I spoke to who has one, agrees with me. Since it corrects itself internally for all of those factors (temp, elevation, etc.) because it's not based on any hard fact to begin with, but the internal gizmo that judges and guessimates speed and distance yes, those settings are important. If you're at 3,000 ft and it thinks you're at sea level the times will be adjusted and therefore inaccurate. At least that's how I've been told it works and why I avoided buying one.

 

Sith...i reccomend you go buy "DragRacing for Dummies".

 

My friend has one and I've borrowed it several times.

The thing just straight out tells you how fast you were going. It doesn't readjust it due to altitude or temp. If you run a 15.0 that's what you ran in those conditions. Go do a netsearch on how an accellometer works and you'll see that what you are saying is non-sense.

The only thing that relies on input is creating that horsepower figure. If you enter the weight than it basically just performs basic mathematics to compare how fast you did 0-60 or 1/4 to the weight of the vehcile and that creates a max horsepower (to the wheels). However, it isn't all that accurate and only gives you peak horsepower.

The 0-60 and 1/4 mile functions are accurate enough for $130 and THEY DO NOT rely on any user input, just suction cup the thing, make sure the thing levels out using the display, press the button and as soon as you move it starts counting.

 

I just don't trust it because it gave some stock 4th gen Maximas 6.1-6.4 sec 0-60, which is just wrong. (I wish it weren't, but that's the truth.)

 

All the GTech meter is is an accelerometer and a stopwatch.

Vf=Vo+(A*deltaT)

The accelerometer basically takes chunks of time (deltaT's)over which the acceleration (A) it feels is the same. For this given amount of time, and given constant acceleration, it can figure out the final speed (Vf) based on the initial speed (Vo). All it does is add up these chunks of time until Vf=60mph. (the chunks of time are very small...maybe a hundredth of a second)

D=1/2*(Vf+Vo)*T

From the deltaT's used above, it calculates the speed after each of these chunks of time, and from that gets the distance the car travelled in that amount of time. For the 1/4 mile all it does is add up these chunks of time until D=1/4 mile.


Hmmmm, no wonder I don't have a girlfriend

As for how the GTech meter can be inaccurate:

If the unit moves, or the suction cup slides a little, it will give a false reading of the acceleration. In addition, its always possible the accelerometer wasn't quite configured properly at the factory. When you are adding up thousands of data points during a run, a slight difference between two units may add up in the end.

In addition, if the road is not exactly flat, gravity may add to the recorded acceleration producing faster than actual times.

 

What a coincidence I just hopped on the org from the weekend.And on Friday night I ran a 15.67 with my GF's brother and his freind in the car he weighs 250lbs and his freind 175lbs...So I am excited right now...But I beleive it is wrong.His freind claims to run 14's in a 1990 4 door 5 speed integra with exhaust and intake...YEAH RIGHT!

 

What I said about the per track thing, is when it's just amateurs running for fun. Some tracks have the clock starts at movement thing and use it for non-pros to get an idea of what their cars can run. But I know people who went to two different tracks and were told that they start the clock at green because they don't have the equipment for start on movement. This is what I was told. In any pro event, it's my understanding that it's go on green, and RT time does count.