- Published on Monday, 18 June 2012 15:33
Various numbers flash on the screen as the car revs higher and higher. Then a bunch of colored squiggly lines appear after each run. Here’s what those lines and numbers mean.
Here’s our dyno chart for a Mitsubishi ASX. The Dynapack chart is divided into two halves, the left one for torque and the right one for horsepower. Torque is measure in lbft and horsepower is simply Hp, not whp, not bhp, just simply Hp. Let’s start first on the right side which is what most people are interested in, Horsepower.
Now think back to how much you hated high school algebra and the much maligned Cartesian Plane with the X and Y axis and graphs. But that’s what exactly a dyno chart is.
The X Axis represents the vehicle’s RPM. This of course varies from car to car. Manual cars usually have the start at 1500rpm, automatics and CVT cars 2500rpm to 3000rpm. The ending RPM is usually the vehicle’s redline RPM, from a low of 4500rpm for diesels to as high as 11,000rpm for high strung all motor Hondas. The segments are usually in increments of 500rpm.
The Y axis represents the power. Dyanpack automatically scales and divides the chart to fit the highest power reading. Increments are usually in multiples of 10 or 20 depending on the power.
Dynapack can display up to six colored graphs in a run session, color coded on the upper left of each chart, red for the first run, up to orange for the last run.
Here’s the part which normally confuses beginners. At the bottom of each chart, there are 2 sets of numbers in green and yellow fields. These represent the crosshairs that can be placed anywhere along the graph, for comparison purposes.
In our Mitsubishi ASX example, the yellow fields show 121.990 for the power, 95 for speed in KPH and 5667 for the RPM where the power is made. The green fields show 127.929, 96 and 5733, which correspond to where the cross has been placed on the graph. Everything the cross is clicked and dragged, the values change. The torque graph is the same thing.
Sometimes you’ll see some really low numbers in the green or yellow fields, relax and don’t worry about it, it’s just the position of the cross hairs. You still primarily look at the X and Y axis of the torque and power graph.
Yes it may seem daunting at first but as you can see, sfter a little explanation, most people find it pretty easy to understand a dyno chart.
You read the Torque graph the same way. The green and yellow crosshairs can also be placed anywhere along the graph line and is independent of the HP graph, since maximum HP and maximum torque normally never occurs at the same RPM.
Next. How to read the Air Fuel ratio graph on a Dynapack Dyno.