The Value Of 3-D Graphing

Here's an example of how a race engineer might use 3-D graphing. Here's one of my favorite examples, collected on EFI equipment mounted in a Crawford Daytona Prototype.

On this car at Laguna Seca we were struggling for front grip and noticed in the load data what might have been signatures of friction in the front suspension rocker assembly. As often happens, the problem was trying to convince an unbelieving team owner what was happening. When we graphed the data in 3-D, the picture became a lot more clear.

What you see in the graph below on the horizontal axis is a plot of the vertical load of one front-wheel load against Lateral g for a whole lap of Laguna Seca. This generates, as would be expected, a strip of readings that follow a surface diagonally across the graph from left to right.

Where it gets interesting is when we put load anomaly on the Z-axis. Load anomaly is one of our calculated channels that compares actual measured suspension load against what you would expect, given the wheel's position. It's a neat way to simulate a shaker rig on the actual car.

In this case, the load anomalies show up as long spikes, a classic indication of large short-term reluctance to move: we had lots of stiction/friction, which turned out to be caused by deflection and binding of the rocker pivot.

You'll notice the graph below is not in an EFI Window. In fact, it was generated by exporting EFI data to Excel and then exporting that into specialized graphing software. That was so time consuming that we asked EFI to incorporate 3-D graphing into their software and, uniquely amongst data system manufacturers, they did it. I wholeheartedly recommend EFI's products.Ron MathisAngerole, Inc

Name Engine Rate
Syntax Deriv (rpm / 60)
Channels rpm
Definition The rate of change of engine speed
Name Brake Bias
Syntax F brake pressure / (F brake pressure + R brake pressure) x 100
Channels Front and rear brake pressures
Definition The ratio of the braking pressures front to rear
Name Heading
Syntax Integ (Gyro)
Channels Gyro
Definition Integrating the gyro channel returns the heading of the vehicle
Name Compare e.t.
Syntax Delta (elapsed time)
Channels Elapsed time
Definition The cumulative time difference between the datum and current lap
Name Gear Ratio
Syntax (rpm / 60) / (speed / (0.680 x 3.1415)
Channels rpm and speed
Definition The ratio of speed between the engine and driven wheels
Name Ride Height
Syntax (FL damper + FR damper + RL damper + RR damper) / 4
Channels Vehicle dampers
Definition The simple definition of vehicle ride height