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DETERMINE AVERAGE MOTOR AMPS OF YOUR CAR

You can do this with a TurboThirty and a battery pack. First, run a cycle on the battery pack using the same charge routine you would on race day and a discharge rate of 20 amps. Record the discharge time of the pack. Next, right after racing, discharge the rest of the pack using the TurboThirty, record the time left over and put the values in the following formulas:

(CYCLE DIS. TIME) - (DIS. TIME AFTER RACE) = (DIS. TIME USED)

(DIS. TIME USED) X (DIS. RATE) ÷

RACE TIME (SECONDS) = AVERAGE MOTOR AMPS

You can use this value as the most important load in your setup program. The TurboDyno loads the motor to six values per test using amps, torque, or volts as steps. We like using amp loads because it can be related to the AVERAGE MOTOR AMPS. By programming a setup with a load range above and below the AVERAGE MOTOR AMPS, and a test voltage of 6.70 volts, we can simulate the actual race conditions of a six cell car.

MOTOR PINION CALCULATION

Another formula you can use with the TurboDyno will calculate motor pinion size based on a motor/pinion combination you are currently using. We believe it is best to base the calculation on a ìknown goodî combination because of the infinite number of variables to be considered. It can be applied to modified as well as stock motors with different RPM values for the same load. Use a program with the AVERAGE MOTOR AMPS as a load and base your calculations on the RPM for that load using the following formula:

(PRESENT PINION SIZE) X (PRESENT RPM) ÷

(DESIRED RPM) = NEW PINION SIZE

STOCK MOTOR RACING

The WATTS value is the most important reading for stock motors. It is the term that indicates the horsepower output of the motor. Since stock motors all have the same number of windings, and battery consumption is normally not a concern, power output is critical. For instance, if you are testing two different stock motors and the first one puts out 15000 rpm, 7 in/oz. of torque, and 85 watts and the second one puts out 16000 rpm, 6 in/oz. of torque, and 90 watts with a 20 amp load, you canít tell which one is better unless you look at the watt readings because one has a higher rpm but less torque than the other and vice versa. Differences in timing, brushes, springs etc. can cause the rpm and torque figures to change, but the watts reading will determine the most powerful combination.

MODIFIED MOTOR RACING

The EFFICIENCY value is the most important reading for modified motors. This is because battery consumption is critical. Low wind modifieds can waste a lot of battery if they operate inefficiently at the AVERAGE MOTOR AMP value(calculated using battery discharge capacity). Changing brushes, springs, and timing will move the efficiency curve to best suit the amp range of operation. For instance: If you calculate your AVERAGE MOTOR AMP value to be 25 amps, the TurboDyno can be set up to hold on a 25 amp load while you adjust the endbell for maximum efficiency reading right on the display. Because of the unlimited possibilities when selecting and prepping modifieds, we suggest obtaining readings from motors that make your car competitive and identifying its characteristics.

GENERAL INFORMATION ABOUT USING THE TURBODYNO

The TurboDyno is a very accurate and repeatable instrument that can measure even small changes in motor output. Much of this is due to the fact that all functions are controlled and corrected by a microprocessor. The condition of the slave motor does not affect readings and the voltage applied to the test motor is consistent and accurate regardless of the load. Direct torque measurement is provided by a true strain gauge in increments of .1in/oz. We have found the TurboDyno to be a valuable tool for making sure motors are in top condition after being setup.Motors can be tested at the track to verify output before the race.