Using an accerlerometer to document performance
 

Some of you guys may own a G-Tech Pro or similar device. For those who do not, it is simply a device that measures g forces (front,back, and side to side) in four different directions. If you have had calculus, you will know that if you know acceleration and time, calculating velocity and distance is a simple mathematical calculation.

G-Tech devices promise the user just that. You plug the sucker into your cigarette lighter, calibrate the machine, and drive. As you go, the device will display g's in four different planes such as braking, accelerating, and banking. Kind of cool.

Thanks to calculus, these devices can also generate 1/8 mile and 1/4 mile data with trap times and speed and all sorts of other goodies such as 60 foot times.

Are they accurate? Technically "Yes". In practise, I am the only one that I know who has used one at the track to compare to an actual time slip. I used it on one launch and it was 0.8 seconds slower than my ticket. I was dissappointed, but not surprised. So, in reality, not really.

HOWEVER (note the trademark bold letters), I believe that these devices have their place. I think that they are great for documenting braking power for learning to stop efficienctly or measuring brake fade. They are also ideal for practising 60 foot times when a track is not available to do this over and over again. Also, I believe they are useful when measuring the results of bolt-ons...or at least those that add enough power to be noticed by the g meter.

Before installing my 4.10's last Spring, I made a number of pulls in all gears with the G meter. Here is what I recorded:

1st - 0.52 g's
2nd - 0.36 g's
3 rd - 0.24 g's
4th - 0.15 g's

After adding 4.10's, the number changed. As you can see, the 4.10's really made a big difference:

1st - 0.63
2nd - 0.47
3rd - 0.36
4th - 0.24

Then this eveing, I repeated the test again. This time, my timing was retarded by 1 degree, instead of advanced by 4 (setup for nitrous) and I had since added UDP's, a mid pipe, and a catback:

1st - 0.63
2nd - 0.46
3rd - 0.35
4th - 0.25

As you can see, the results are nearly the same.

Then, I repeated the experiement with a 100 shot of nitrous. Bottle pressure was only at 600 psi since I don't yet have my heater installed, so I figure that that the 100 shot is probably closer to a 60 - 70 shot in reality, but hard to say. Here are my results:

1st - 0.62 (traction limited)
2nd - 0.54 (18% higher)
3rd - 0.40 (14% higher)
4th - 0.29 (16% higher)

Take note you n/a guys with stock gears! As you can see, my car with spray now accelerates quicker in second than it did in first before the gear swap. If I was at full pressure, I would probably hit close to 0.60 g's in second gear.

The added g's certainly will translate into a quicker trap.