Steering improvements¶

zoompilot reverse-engineered the Mazda steering hardware so the electric power steering (EPS) works to its full potential. The approach is data-driven: every constant is measured, logged, and validated against thousands of miles of driving.

Speed-dependent torque¶

Stock openpilot uses one lateral acceleration factor for all speeds. zoompilot encodes the EPS's full torque curve instead. The result is more confident steering in neighborhoods and fewer wobbles on the highway.

Speed-dependent tuning¶

The EPS behaves in a non-linear way across speeds. Instead of one tune, zoompilot learns across seven distinct speed ranges and applies the right one for your current speed.

Self-tune does the learning in the background. Fresh installs on 2022+ EPS Mazdas start from seeds learned on a real CX-5, so the car steers well from day one and improves from there.

Rate-matched commands¶

zoompilot asks for the EPS's maximum of 12 units per frame, up from stock openpilot's 10. Torque ramps up faster, so the car reacts to curves sooner.

Factory-matched specs¶

The steering ratio, vehicle mass, wheelbase, and lag are set to Mazda's real figures, then refined against driving data.

Steering to zero¶

On the 2022+ EPS rack, zoompilot steers down to 0 mph. This also covers older Mazdas fitted with a swapped 2022+ rack, identified by EPS fingerprinting. See Supported cars.

Design details¶

The full evidence and design record lives in the technical section:

• Mazda lateral: evidence and design notes
• Lateral tune: v2 torque controller
• v2 torque tune roadmap