EPS (electric power steering) actively self-centers steering for 2017 (video)

[MetroMPG]

[Admin note -- this topic split off from thread: Darin's test drive review notes: 2017 Mitsubishi Mirage G4 sedan CVT ]

The steering feel and self-centering in the 2017 Mirage is much improved, as seen when comparing strawboss' 2015 Mirage hatchback against the 2017 Mirage G4 sedan.

When I started driving the car around town, I suspected that the changes were in the EPS (electric power steering), not in the physical steering setup.

I confirmed it with a little test to see how the car's steering centers at low speed with no driver input:

Test #1: EPS disabled

1) Turn the steering 90 degrees with the car stationary, in an empty parking lot.
2) Let off brake and accelerate VERY gently up to 25 km/h (15 mph).
3) Watch how far the steering wheel returns towards center on its own (no driver input) .

Test #2: with EPS enabled

1 - 3) Repeat steps 1-3, above.

Here's what happened.

Steering wheel starting position, car stopped:



Result of Test #1) EPS disabled, steering wheel end position @ 25 km/h:

The steering gradually unwinds to around 1/8 of a turn, then stays there even as speed continues to increase.



Result of Test #2) EPS enabled, steering wheel end position @ 25 km/h:

The steering gradually unwinds at first (like with EPS off) as the car starts to move, then unwinds more quickly to near center.



What I noticed is that with the EPS enabled, it actively un-winds / straightens (almost) the steering when the car passes roughly 10 km/h (6 mph).

It's something I suspected it was doing, because sometimes it felt like the self-centering wasn't linear. At certain speeds, and at certain steering angles, when you're letting the steering wheel slide through your hands after a turn you may feel it unwind slightly more quickly/forcefully at a certain point.

I even made a short video. Active self-centering happens at around the 6 second mark: