9. Power Steering pump
Since the BMW originally had it's power steering pump driven off the gas engine, an alternative is needed. This Toyota MR2 power steering pump is a likely candidate:
It's internal 12V electric motor is designed to run full time and is smart enough to know when to idle back when not being used to reduce power consumption.
It also has a digital input that gradually reduces the motor speed (and thus power level) when the need diminishes, i.e. on the highway.
All other components from the original power steering system will be used.
I purchased the original Toyota connectors which are very high quality O-ring sealed interconnects. It just so happened that I was able to use a left over 50A circuit in the BMW that was used for the exhaust emission control pump, which was exactly the supply capacity needed to power this pump.
The result is perfectly normal power steering feel, whenever the ignition switch is on.
This is a late model spyder MR2 pump
When I tested the fit in the planned location, to my delight it fit like it was made for it. Luck happens..
The plumbing of the high pressure output aligns directly with an opening just below the chassis structure where it has a short and straight path to the steering rack hydraulic input. The low pressure return to the fluid reservoir, pointing to the left in this photo, can be pointed any direction which should ensure a good route path.
This inner fender panel completely encloses the pump.
It's visibility and access to the filler cap makes for a great location. This corner is accessible when the battery pack and the contactor box are installed.
Jan 2010 update:
The mounted pump:
With bracketry oriented in both horizontal axis, the pump mount is very solid and has rubber isolation to prevent vibration in chassis.
The return fluid hose goes into a small mouse hole on route to return reservoir
I will detail the electrical drive for this when I get some time...
