G-Meter Operation
The basics of G-Forces
When you’re not performing a Timed Run, the Perfor-
mance Computer is in the G-Meter Mode, where it can
display the acceleration, braking, and cornering forces
of your car.
These forces are measured in “G’s,” and they are the
best way to measure your car’s performance. You’ve
felt these forces—when a powerful car “pushes you
back in the seat,” when a panic stop presses you for-
ward against the seat belt, and when a sharp corner
presses you against the door panel.
What the G-Meter shows
The G-Meter displays the G-Forces exerted by your car,
in the plane of the road. On a perfectly level surface,
the G-Meter will read zero when your car is not mov-
ing, or when it is traveling “steady-state” (not acceler-
ating, braking, or turning).
However, on hills or sloped surfaces, the G-Meter will
show a small G-Force, even when your car is not mov-
ing. This shows the force your tires are exerting to keep
your car from sliding down the slope.
TO SELECT G-METER
Press and release the G-METER button
to choose the G-Meter mode.
Press and release the button again to
select different G-Meter display options.
To Calibrate the G-Meter, park on a level
surface, then press and release the
CALIBRATE button.
WARNING!
This device measures G-Forces, but remember, it does
not change the laws of physics. Under certain circum-
stances, almost any vehicle can roll over, causing seri-
ous injury or death. Taller vehicles such as SUVs, trucks
and vans are more likely to roll than conventional cars,
so even more care needs to be taken with those ve-
hicles. No electronic device can take the place of the
driver’s judgment.
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Specifications
Accelerometer
2-axis, +2G range, high-resolution digital outputs.
Processor
Advanced RISC-based 8-bit microcontroller with 128KB
Flash Program Memory, 4KB SRAM, 4KB EEPROM,
integral 8-channel 10-bit A/D convertor. Throughput
up to 14.75 MIPS at 14.75 MHz. Additional external
1MB flash memory for data storage.
Temperature Compensation
Factory-calibrated. Internal digital temperature sensor
provides real-time continuous temperature compensation.
Power Regulation
Ultra-stable high-efficiency digital power supply with
secondary 5 volt regulator for accelerometer power.
Display
Vacuum Fluorescent Graphics display, 1792 pixel.
Housing
Polycarbonate/ABS alloy. Aluminum mounting bracket.
Dimensions
5.5”W x 1.7”H x 1.4”D., Weight 5 oz.
Power Requirement
12 volt DC Negative ground, 250 mA typical.
How it works
The Performance Computer measures
the performance of your car by sensing
acceleration forces.
An internal precise digital 2-axis accelerometer tracks
your car’s acceleration, braking, and cornering forces
approximately 200 times each second. A built-in com-
puter continuously analyzes this data and calculates
corrected G-Forces for the G-Meter operation, and speed
and distance data for the Timed Run operation.
Your Performance Computer was developed and tested
extensively, both at drag strips and using our VBOX
professional vehicle testing equipment, the ultra-
precise data acquisition system used by auto makers
BMW, Honda, and AMG Mercedes; race teams Ford
Racing, Roush Industries, Chip Ganassi Racing, and
Renault F1; tire manufacturers Michelin, Bridgestone,
Goodyear, and Kumho; and car testers at Car and Driver
and Automobile Magazines.
The result is the most accurate accelerometer-based
performance computer available. And it’s the first unit
with true one-button operation: Press a single button
for calibration, a single button for G-meter operation,
a single button to start a timed run, and a single but-
ton to review your previous runs.
