# MR2 steering pumps (again)



## subevo (Aug 23, 2008)

ok just done my matiz.the mr2 pump has a J.I.C. type thread .the problem i had was that i couldnt get an exact match from pirtek who make power steering hoses.i could get the same thread but the fitting had an inverted cone shape as opossed to the mr2 which was the oposite way.solution was to cut the hose fitting square at the end then use an oring to make the seal . i also used loctite thread locking compound to seal the threads incase the o ring leaked.no leaks yet.does this make sense .if not let me know.


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## subevo (Aug 23, 2008)

forgot to say .its the mk3 pump im talking about.the pirtek engineer said i couldnt seal it with a banjo bolt and dowty washer due to the j.i.c. fitting having a much reduced diameter after the thread ends compared to sae fittings.the o ring im talking about was approx 5mm thick and is compressed when you screw the fittings into each other.


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## electricmini (Oct 21, 2008)

Hi everyone,

I've managed to get my mk2 MR2 pump working with the Supra's power steering. I got a short 1ft hose made up by my local Pirtek centre, plus a couple of adaptors to engage into to the MR2 pump. There's a very slight leak at the pump outlet, so I might need to change the adaptor, but apart from that it works well.

MR2 pump's current draw is approx 25 amps with no steering input (idle), while the current draw with a heavy load (e.g. a housebrick blocking the roadwheel or the steering at full lock) is approx 65 amps. This was measured using my clamp-on current meter, with a rather cold 12V AGM battery supplying the juice.

So a 100 amp fused circuit connected straight to the 12v battery (with a big relay/contactor) should do the job just fine. I'm already planning on a beefy DC-DC, with approx 80A output (Vicor/Westcor MegaPac PSU).

So apart from the whine of the pump, that's another thing ticked off the list 

I managed to get every last scrap of the fuel system off the car on Sunday, even the fuel lines. There are some nice multi-tube pipe clips which hold the fuel and brake lines in place under the car, should be just right for locating a cable-tray as well for the main battery cables.

Next up is making the battery racks, and getting my auxilliary 3kW AC servomotor to idle the auto gearbox & run the aircon pump.....

Richard (electricmini)


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## subevo (Aug 23, 2008)

glad to see you got it sorted.i also checked the pump at idle with a clamp- meter and got 11amps at idle.im only using a 30amp relay which i had spare.no problems yet but time will tell.


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## PatricioIN (Jun 13, 2008)

yes, I have only 30amp relay as well and have not had any problems in over 500miles of EV driving... yours seems to be pulling a LOT of amps.


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## electricmini (Oct 21, 2008)

Yes, I thought the "idle" amps looked a bit high as well, but this
is the mk2 MR2 pump, not the nice mk3 one with the integrated reservoir

However, this was just the pump powered up - the Supra's
progressive power steering ECU wasn't powered, nor was the rest of the car!
This ECU adjusts a solenoid inside the rack, which varies the amount of hydraulic assist according to road speed.

Maybe without that running there's more restriction in the hydraulics, making the pump work harder.

I might look at getting rid of the stock fluid coolers as well, they take up valuable room at the front. With a lead-acid pack, the car's not going to run for hours on end, so a smaller cooler tucked away somewhere would probably do - or even a loop of metal pipe running through a hot-water tank
(been looking closely at the "Liquid Heater Success" thread)


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