Electric Power Steering
12/11/2010: Moving the pump down below the frame rails. This will move weight lower and make engine bay looking stock OEM.
Otherwise no issues so far with the system.
05/09/2009: Electric power steering is now installed and works great. Autronic controls steering assist as follows:
- Engine speed has to be between 600 and 3000.
- Speed has to be between 0 and 50.
- 100% assist up to 15km/h, then decays down to 0 at 50km/h.
If engine and vehicle speeds are outside the limits, pump is stopped.
Installation was relatively easy and is mounted next to ABS unit, OEM reservoir and original hoses are used.
Only small hydraulic adapter was needed to connect the high-pressure hose to the pump. Pump is controlled with 100A solid state relay.
04/01/2009: One of the projects I have been thinking for a long time has been the Electric Power Steering system, but pumps are not that easy to find.
Finally I found a used Toyota MR2 pump from Ebay, One of the biggest reasons I wanted to do this is that I can make the steering pump “assistance” adjustable by speed from Autronic. Autronic already knows the car’s speed and I have one extra PWM output free, which I can use to control the pump.
Autronic can’t drive the pump directly since the current draw by the pump is very high, for thsi reason pump is controlled by HFS33 Solid state relay, current capacity is 80A. Big heat sink is used and installed outside the engine compartment.
Below is a voltage table Toyota uses:
| Speed | RPM Voltage |
Voltage at Motor |
| 0 | 0 | 0 |
| 0 | >0 | 9-11V |
| >40 | >0 | 2-4V |