Ok here are some findings. Firstly I am told the early Astra's run a different pump to the one I have tested. The early electric pumps were made by ZF and were very heavy (cast steel body), I estimate double the weight to the aluminium body version I have which is made by TRW. The time taken for the pump to wind up to full speed and pressure is 19 seconds. The pump then drops back to a constant run speed in total 22 seconds to complete the start up cycle. Although you could probably have enough hydraulic assistance to move the car out of the shed in around 10-12 seconds, but if its turn the wheel to full lock with your foot on the brakes then your going to need around 18 seconds.
I have also been told that the ZF version draws a lot of amps but its not the case with this TRW unit. It starts up very slow and its not until the 4 second mark you can actually hear it whizzing away. During this stage the pump only draws 1.98-2.3 amps. I seen a peak of 5 amps then hold steady at 1.97 Under partial load the amp reading registered around 5 amps and at full load approximatly 16 amps. Although I did see a peak of 24 amps when cold. The racks are happy to run around 900-1,000 psi but can take 1,500 and still give good assistance with a low pressure of 750 psi.
The pump supplied a hydraulic pressure of 1,150 psi cold (pressure relief) and after I operated it for 20 minutes the pump produced a touch over 1,000 psi. I probably should have used the special synthetic oil but it seamed to run fine on Dextron 3.
As for the wiring there are 5 wires in total main positive
12v supply, 8mm wire
And three small wires approximately 1.5mm
I put the three small wires to the positive battery terminal to get it to work. I haven't been able to source a wiring diagram to suss out the connections. However I think one would goes to the alternator indicator light circuit so it only allows the pump to start up once the engine is running, this allows the starter motor and ignition to get full voltage on cranking. A second wire may go to some speed sensor device not sure and the third I haven't got a F**king clue without finding a wiring diagram. Anyway it works fine on the bench. I don't know how many km this pump has done and the car I remove it from looked a bit worse for ware. I must say it draws much less electrical power than I was expecting or the meter I have isn't reading correct.
If you are struggling to find room for a belt driven pump or you have a special setup that doesn't allow for an extra accessory drive than this pump might be a good alternative. Its very basic to install and can be mounted almost anywhere so long as you have access to check and top up the fluid. It could be mounted down the back somewhere but you would need to be mindful of pressure and voltage drops over long distances. If you have a lot of electrical power hungry equipment in your car I would recommend running a 85 amp alternator as a minimum. It all ads up, especially when driving at night and an A/C going the extra couple of amps might be enough to take the edge of the battery on the next start.
They can be picked up relatively cheap, the hoses and fitting cost three times the price of the second hand pump but the hoses and fittings for a belt driven pump would cost the same. The pump didn't heat up much during the time spent testing so maybe they don't require any additional cooling assistance(oil cooler) in the system when worked hard example, (track work). One last thing you would want to retain the rubber mounts if using this pump as they do get a bit of noise happening when they are operating load or no load. Probably wouldn't hear it over the exhaust on a average V8 Torana running if mounted correctly.
I get comments from owners saying they cant put a belt drive pump in their Torana, I get that and there are cases where this pump could be the way to go. But don't write of the belt driven pumps. Both my cars have A/C and power steer and driven by serpentine belts, nice and quiet, no belt slip and no need to constantly adjust v-belts, and very reliable. I don't have a lot of space around the front of my engines but with a bit of thinking its not that hard to get it all to work.
Do I have a preference ? nope I'm not going to get into that debate.