Re-Purpose power steering pump
 

This is sort of a re-post but not in it's own thread and not to mention I didn't get all the info I needed previously probably because it wasn't seen by all of you Geniuses here. Thanks to all who posted in the other thread I asked about this in.

I'd like to use a power steering pump to provide pressure to a remote mounted turbo and also scavenge the oil from the turbo. This is on a Mazda Miata which has had the PS "depowered" which leaves the pump in place looped to itself with no job.

-I would use a return style FPR to regulate oil pressure to the turbo, ~30psi is the norm.

-This would be an independent oiling system loop just to the turbo. The long lines would provide cooling or I would provide additional cooling as needed. I'd either use power steering fluid or the appropriate motor oil.

-Using the PS pump instead of engine oil and an electric oil pump for scavenge return seems simpler and more reliable to me since it will be functioning much like it has it's whole life. I also won't be relying on an electric scavenge oil pump. I can adjust oil pressure without using a small restrictor jet in line.

I have gotten some feedback from friends and other site members but the question has made some go full on crazy like saying it won't work because PS fluid is not petroleum based so the pump won't work with motor oil or that the pump makes 1,000psi all the time and there is no way to regulate it lower. I do appreciate all feedback but I'd really love to hear from someone who has used a PS pump in a way other than to power the rack.

So, I guess what y'all are trying to tell me with 71 views and no comments is that I will be blazing this trail my darn self?

It looks to me that since the rack is below the pump and reservoir, on my Miata at least, the pump provides some suction on the return side so as to scavenge the fluid once it flow thru the rack. Can anyone verify this assumption on my part is correct? I will do some testing before buying fittings and hoses to make sure it will act like a scavenge pump since this is half of the reason I wanna do it.

It's an interesting idea, but I haven't tried it myself and didn't want to offer any unfounded speculation. But if you need unfounded speculation as there seems to be no experience to be had:

1. The pressure is not just a function of the pump but of the amount of restriction. A bypass type regulator should be able to regulate it down.

2. I'm not sure if the seals are compatible with oil or not, but power steering fluid is a hydraulic oil, and I'm pretty certain it is petroleum based. So my guess is the seals SHOULD work.

3. The return side usually ISN'T scavenged by the pump. The fluid on the return line gets pushed into it by new, incoming fluid from the high pressure side.

So you'd probably either need to mount the turbo oil reservoir above the PS pump and have it gravity feed into the pump, or use an electric scavenge pump.

Thanks Matt, I agree that with a hydraulic system you can have the fluid on the low pressure side pushed back to the reservoir by incoming fluid from the high pressure side without any issues. This is a big no-no for a turbo bearing and seals though.

A separate closed loop lubrication system for the turbo is a nice advantage even if it needs an electric scavenge pump. This pump would have to overcome the pressure of the return line from the pressure regulator though which could be pretty high. Would it be the same as what the regulator is set to assuming I used a return style FPR?

After further review, without the benefit of mechanical scavenge which would eliminate the need for an electric pump, I'm not seeing any real advantage to going this route.

I wonder if I could use this high power steering pump pressure to spin a turbo? Move over Turbulator, here comes Hydraulic Turbo. :D

With a return type regulator, the pump would only be putting out the amount of pressure the regulator sets - in your case, 30 psi.

There have been a number of attempts to drive a supercharger off the power steering pump; none have worked very well that I'm aware of.

This is a very interesting idea.

First off trans fluid should not be a problem it is basically oil with a tremendous amount of detergent in it. I would however recommend you use one rated for high temp. Most transmissions only see 225-250 deg. More than that and bad things happen. I think I would scrap the trans fluid and go with a premium grade high detergent motor oil. Amsoil comes to mind but there are many others out there.

As for the return. you need to have a collection point below the level of the turbo that the oil can flow to if you try to push the oil back to the pump through the turbo it will push it through the seals. Just have the power steering pump pump from the collection point. This would actually work very well with a rear mount system. Sizing of the lines would be key and I would want to put an oil pressure sending unit on the line near the turbo with a gauge wired to it that I could monitor it. I would be particularly careful on cold start up to make sure that you don't go in to boost until you see oil pressure at the turbo.

Other than that I see it as a great idea. Another thing to think about would be some sort of recirculation of the oil through a cooler and back to the collection point. I bet the pump has the capability volumn wise to provide enough oil to both the turbo and to a cooler. It would take a little bit of fiddling with the pipe sizing but it would ensure a nice cool supply of oil all the time. The only other thing I can think of is to put a remote mount oil filter in the system.

IMHO, engine oil is the easiest way to supply oil pressure to a turbo. The oil pressure already exists and the turbo only uses a trickle. Getting it back to the pan is the issue with a rear mount arrangement. If this issue will also exist with a separate oiling loop system then I don't see any advantage to the added complication or weight, engine drag etc.

I have two small electric scavenge pump candidates.

-One is a pump designed to scavenge on turbo motorcycles where the turbo is almost always located below the oil pan.

-The other is a Holley Red fuel pump designed for carburetors, high volume, low pressure. I know engine oil can destroy actual rubber but if it is fuel tolerant then will it be ok with oil? If not I'll replace the two or three seals with Buna-N or silicon or whatever material necessary. One is a flat piece, the other is an o-ring. The rest of the components are metal.

Thread Revival. I know y'all have been waiting to hear my latest harebrained idea, sorry for the delay.

What would it take to convert a high pressure hydraulic pump like a PS pump into a scavenge pump? A pump that will provide vacuum on the intake side and some pressure on the pressure side but not as much as before?

The pump I have is the OE Miata pump. It is small an the back cover bolt on.
https://www.homemadeturbo.com/attach...ine=1357780251

Could I just machine away some of the area around the impeller so it would create a vacuum instead of pressure? You probably wanna see what the inside looks like don't you? I have one for experimentation purposes so I'll get the back cover off.

Thanks for waiting so patiently for me to get back with y'all. I didn't take any pics but the pump is a vane type so it should pull vacuum on it's own. I'll have to experiment to make sure it will do what I want it to do.