What shock travel data is good for
A shock travel sensor is a linear position sensor mounted alongside the shock absorber. As the suspension moves, the sensor's shaft slides in and out and its output voltage changes. Logged against everything else the ECU records, that tells you a lot:
- Drag racing: how the rear squats and the front rises on launch, and whether the tire is shaking. Tire shake shows up clearly as a rapid oscillation in the trace.
- Road course: whether you're bottoming out, how the car pitches under braking, and how much roll you're getting in corners.
- Setup changes: a before-and-after comparison when you change springs, shocks or ride height.
NSP has a separate channel for each corner: front left, front right, rear left and rear right. They're all set up the same way.
Hardware
Haltech's linear position sensors come in different stroke lengths, such as the 100 mm (about 4 in) travel sensor and the 200 mm (about 8 in) version. Pick one with more stroke than your shock so it can never bottom out or overextend. Mounting options include split collar mounts that clamp onto the shock body and weld-on tabs.
Wiring
Travel sensors use an analog input, and any spare AVI will do. Assign it on the Wiring node for that corner and disable the pull up. These sensors are powered from the ECU's 5V supply and drive their own output, so an extra pull up would only skew the reading.
Calibration and units
The main node for each corner holds the calibration that converts voltage into travel. You can type it in or use Load from File, and Save to File keeps a copy for the other corners or your next car. If you'd rather see inches than millimeters, change it under Preferences > Unit Options.
Decide what your zero point is before you calibrate, whether that's fully extended or ride height with the driver in. Use the same reference on all four corners so the traces can be compared directly.
Display range
Display Minimum and Display Maximum set where number displays, gauges and bars for this channel start and end. Set them to cover the sensor's full working range so no movement is cut off on screen.
Diagnostics
The Diagnostics node can raise a code when the signal voltage goes too low or too high. Suspension sensors take a beating from heat, debris and constant movement, so these checks are a good way to catch a broken wire or a sensor that has come loose. You can give each one a DTC severity that triggers an Engine Protection level, although for a data-only sensor we'd usually just log the fault and not pull power.
For other sensor channels, browse the knowledge base, or ask us about the right sensor and mount for your shocks.
