Edelbrock QwikData 91001 Manual page 18

Shaft Speed Example
The following calibration values should be used to measure shaft speeds on a shaft with two magnets (i.e. 2 pulses per revolution).
This will result in a frequency of one half the tach signal in the prior example.
Thus, assuming the same 9000 max RPM, the input frequency is only 300 Hz. Thus the second element contains the numbers (3),
(9000). The third element is (0), (0) which indicates to QwikData that this is the end of the calibration table data.
MPH Example (Measured at Driveshaft)
The input type should be set to "Frequency Rise". To measure the vehicle speed, you need to calibrate a speed sensor mounted on
the output drive shaft.
To complete the calibration, you must know the rolling radius of your rear tire and the Final Drive Gear Ratio. To determine the rolling
radius of your rear tire, measure the distance from the center of the wheel to the ground with the car fully loaded and on level ground.
Use the following formula to determine appropriate table value to enter into the calibration table. (See the Manuals section of the
QwikData CD-ROM).
Example:
Calib. Value =
Turns/Mile =
Note: Choose a Maximum speed higher than the car can achieve. This number does not have to accurately represent the actual top
speed of the car. To simplify the calculations, pick an even number like 200 or 250, etc.
Catalog #91001, 91003, 91004, 91005, 91007, 91009
Rev. 9/06 - RS/mc
No. of Magnets x Max MPH x Final Ratio x No. of Turns/Mile
63360 (Inches/Mile)
Rollout (2 .x Tire Radius x 3.14)
Max MPH =
Tire Radius =
Final Drive Ratio =
No. of Magnets =
Result=
360000
Page 15 of 47
200
12.5
4.10
2
3.67
©2006 Edelbrock Corporation
Brochure #63-0282