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The main analysis function is the acceleration simulation. Choose standing start or rolling start modes. Shown are the speedometer, tachometer,
time-to-speed, and time-to-acceleration plots. The data panel displays the 0-speed and 0-distance results as they occur. The simulation
is controlled through the ten buttons beneath the data panel. The speedometer, tachometer, and plot windows may be closed at any time to
speed up the computations on slower computers. A real-time speed limit option slows down the simulation for those with faster computers.
The acceleration time-to-speed and time-to-distance milestones are user-defineable.
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In addition to the up to 38 specifications used to define a car, the CarTest model is controlled by a set of 54 general model parameters.
You have access to these suggested default values and can change them at any time.
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To store a custom set of model parameters and associate them with only one car, you define a set of car-specific model parameters.
These values add the capability to define a custom horsepower curve at 500 rpm increments up to 20,000 rpm. This curve may be defined as being
measured at the flywheel or directly at the driving wheels. Dissatisfied with the optimum shift points CarTest suggests? Here you may
specify your own numbers. User-specified lateral acceleration values may be specified to override
the calculated values for track testing.
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Some of the CarTest data analysis functions include the ability to produce Horsepower and Torque curve plots,
view the Power Loss Curves to evaluate component power losses, examine the Drive Power Curves and determine optimum shift points,
evaluate the theoretical Speed in Gears, and compute Skidpad and Slalom course performance.
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While you may control the launch parameters in the acceleration button panel, you can let CarTest determine the optimum launch
technique for your car. Select the acceleration criteria, 0-60 mph or 0-100 km for example, and CarTest will find the launch method and
launch rpm that produces the fastest acceleration time.
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The Fuel Economy function computes the EPA Highway and City fuel economy estimates. Also shown are curves of constant speed fuel
economy in each of the gears and the actual City and Highway driving schedules.
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One of the most useful functions in CarTest is the parameter sensitivity analysis. Each of the car specifications or model parameters that
can be automatically varied and an acceleration run of your choosing is computed for each value of
that parameter. Choose the percentage variation of the parameter and the number of intermediate analyses.
For example, vary engine horsepower and see what effect that has on 0-60 mph acceleration time, or vary environmental parameters
and see how temperature, elevation, or barometric pressure affect performance. Be sure to access the general
model parameters first so they appear in the selection list. The Horsepower Finder function allows you to enter an elapsed time
for any acceleration criteria you specify, either time-to-speed or time-to-distance, and the program will compute the power and
torque required to produce that result.
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Any plot produced by CarTest can be expanded to full screen for easier viewing. In addition, the mouse cursor acts as a digitizing
pointer with the x and y coordinate values of the location of the mouse displayed in the window title bar in plot data units. You can also
use the mouse to draw a rectangular box on the plot that defines a zoom in region for a new plot containing only that data.
You can reconstruct the full plot at any time. The actual data points that determine the plot can also be optionally shown.
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