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Thread: Electric power steering pump

  1. #1
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    Electric power steering pump

    Hello all, I am converting to electric power steering due to space constraints on a build, and will be using a mini copper pump. From what I am told, this is not uncommon with BMW road race cars, so I thought id check in and see if anyone had any experience with it. It appears pretty straight forward as it is a pretty self contained unit, however there are some details I am still researching. Thanks guys

    -Wiring: The larger plug is pretty self explanatory, ill likely run it on a breaker rather than a fuse, whatever rating mini uses. The smaller plug is what is unknown to me. It looks like one wire is for key on or engine on signal, another is for an alternator (?), and the other is for diagnostics. I do not know the exact logic that Mini uses, but I am guessing the alternator signal is either for power requirement verification or a signal that will turn the pump on after the engine starts rather than during cranking.

    -Plumbing: The output fitting is a bit unique, do you guys modify the factory hose or is there a fitting that can be used to adapt it to a more common fitting style. I have seen an Australian company that looks to have made a fitting that converts the output to -6 AN (JIC), but they will not sell it to me. Also, does the reservoir input have to be in a certain orientation? It looks like it can be rotated anyway you choose just by loosening the worm clamp

    -Reservoir: I will be using by cars factory reservoir, however, I believe there is a restrictor on the factory Mini reservoir. Im assuing this should be maintained for proper operation

    -Cooling Fan: Most of the retrofits I have seen do not retain the fan, however all the factroy Mini articles I see, say that the fan is the cause of most pump failures. Is this due to the place its installed in a Mini or does the pump just create that much heat?

  2. #2
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    I was going to go with a mini pump. But the Volvo pumps don’t need cooling fans so I decided to go with that.


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  3. #3
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    Quote Originally Posted by TTGZDOG View Post
    I was going to go with a mini pump. But the Volvo pumps don’t need cooling fans so I decided to go with that.


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    Thanks, I haven’t heard of using the Volvo pump, mostly mini and mr2. Is the Volvo unit self contained like the mini? Wiring wise. Also, does the mini pump really need a fan if it located away from heat? I have seen installs without it, but I also hear that pump failures are due to bad fans

  4. #4
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    Vauxhall Astra (possibly Saturn Astra?) from the mid 2000's has a standalone pump - same one that's used as the "motorsports" EHPS sold by Porsche for $1500+.

    It just needs power and ground, and one other wire connected to the switched power wire I want to say (alt sense wire in original car).

  5. #5
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    I have read the same thing about the mini pump needing a fan. I’m sure it’s required honestly. Or else it wouldn’t have one from the factory. And yes the Volvo unit works just like the mini and mr2 pump.

    https://youtu.be/Htrz_Wn4SZ8


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    I managed to get one off eBay for 66$ used !


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  7. #7
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    Quote Originally Posted by TTGZDOG View Post
    I have read the same thing about the mini pump needing a fan. I’m sure it’s required honestly. Or else it wouldn’t have one from the factory. And yes the Volvo unit works just like the mini and mr2 pump.

    https://youtu.be/Htrz_Wn4SZ8


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    That was actually a very good video, he was really thorough and clear. Unfortunately, I can’t fit that pump in my engine bay, so the mini pump will have to due. Everything aside from the trigger wire and the pressure hose seem straight forward. The trigger wire I am sure I can configure and output from my Haltech ecu, so that I’m not overly concerned with. The pressure hose, I can’t seem to find anything. I can get a used line, and try hacking it up and getting a -6 brazed or welded on, but that is not desirable to me. What is really like to do is find out what fitting that is and just make the adapter. It appears to be a simple o-ring fitting that gets held in place with a tab and bolt, but the dimensions of the fitting are unknown. Looks quite easy to machine and weld up. What does everyone else do?

  8. #8
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    I couldn’t find the size of outlet either. Lol


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    Quote Originally Posted by TTGZDOG View Post
    I couldn’t find the size of outlet either. Lol


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    there is a company in Australia that has an adapter fitting to -6 AN, but they wont sell it to me on its own. I think I will have to just buy a factory hose and try to duplicate it or modify it. As for the wiring, in my opinion, I would want the pump to engage after the engine has started, rather than key on. Between the starter, fuel pumps, and that steering pump, that battery is not going to last, and the engine will struggle to start. That why I thought that alternator was used as the trigger, as the alternator would not be putting operating voltage until the engine in running. Of course, I have the advantage of the standalone ECU, but I dont know if it is a ground signal, a power signal, a momentary signal, a continuous signal, or none of those.

  10. #10
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    Well if you buy it then you can just measure the threads and buy a an fitting that works.

    This guy has a little insight about how to wire it.

    https://youtu.be/DRfDDlwVnzk


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  11. #11
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    Quote Originally Posted by TTGZDOG View Post
    I have read the same thing about the mini pump needing a fan. I’m sure it’s required honestly. Or else it wouldn’t have one from the factory. And yes the Volvo unit works just like the mini and mr2 pump.

    https://youtu.be/Htrz_Wn4SZ8


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    Quote Originally Posted by TTGZDOG View Post
    Well if you buy it then you can just measure the threads and buy a an fitting that works.

    This guy has a little insight about how to wire it.

    https://youtu.be/DRfDDlwVnzk


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    Yes, I’ve seen that video. Unfortunately, the outlet of the pump has no threads. It has a machined bore for the o-ring fitting, and a threaded bolt hole next to it to bolt the line on. It will have to be made or the stock one modified

  12. #12
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    Just tap it to whatever size you want. Harborfright gas a nice titanium set for 90$ you can use the 20% off it’s about 70 total after that. I bought it for one use and I’ve ended up using it bout 15 times this month just cleaning up nuts and bolts in my e36 as I was working on it.


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  13. #13
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    Yeah I’d probably get a hold of the stock outlet and just cut the rubber part off make a little flange and hose clamp your hose to it.


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  14. #14
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    I would definitely put a fan on the pump lol.


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  15. #15
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    Quote Originally Posted by TTGZDOG View Post
    I have read the same thing about the mini pump needing a fan. I’m sure it’s required honestly. Or else it wouldn’t have one from the factory. And yes the Volvo unit works just like the mini and mr2 pump.

    https://youtu.be/Htrz_Wn4SZ8


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    Quote Originally Posted by TTGZDOG View Post
    Just tap it to whatever size you want. Harborfright gas a nice titanium set for 90$ you can use the 20% off it’s about 70 total after that. I bought it for one use and I’ve ended up using it bout 15 times this month just cleaning up nuts and bolts in my e36 as I was working on it.


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    Dude, I never thought of that. I will check the bore and see what tap is closest. I could tap it on the mill and maybe tap it for an ORB fitting. Thanks for that

  16. #16
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    Pretty sure the hole looks to me atleast to be around 3/4 to and inch deep.


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  17. #17
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    Quote Originally Posted by TTGZDOG View Post
    Yeah I’d probably get a hold of the stock outlet and just cut the rubber part off make a little flange and hose clamp your hose to it.


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    If you're talking about the pressure side, that ain't happening, lol ... the hose is rated for like 1500 PSI for power steering hydraulics ... a hose clamp will be about as good as rubber band.
    Check out the 8legs Racing page: https://www.facebook.com/8legsRacing/


  18. #18
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    Quote Originally Posted by TTGZDOG View Post
    Pretty sure the hole looks to me atleast to be around 3/4 to and inch deep.


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    I measured the bore today, is is .433, the closest tap being M12x1.25, which is a .4291 drill size. The hole is a bit shallow though, and the top has a recessed landing for something, maybe a seal, or just to center the factory fitting. I think I am going to just pick and old line, and see what it looks like. If it is what I think it is, I think a proper adapter can be made relatively easy. Ill report back with the progress.

    I am still unclear of the trigger wire however, does anyone know someone who has done this?

  19. #19
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    The old man in the video explained it I believe. And as fat hose clamps I got most of my ps hoses connected that way lol.


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