Would decreasing the size of the hose from the reservoir to the pump increase efficiency/performance?

My PSC reservoir sits high and I realize lower would be better. I have the output on the reservoir a little lower than the intake on the pump...I know it's best if they are at least level. The output on the reservoir is -10AN but I used an adapter to get to -12AN as from my measurement, the intake on the pump was about that size. Come to find out I can make -10AN hose work just as well...probably with a better fit on the pump.

So is it worth it to swap out the -12 adapter and hose with the same in -10? Power steering and brakes work fine, but I feel it bog down and I lose some power steering when I'm making a tight turn....like while braking and turning into a parking spot.

In the pics you can see the hose routing (black hose), as well as the huge-ass -12AN 90 degree hose end off the reservoir.

If anything, decreasing the hose size on the low pressure intake of the pump would decrease performance. You'd see increased frictional losses, since more of the fluid moving through the hose is in contact with the hose wall. In almost any pumping application you want as large a feed hose as possible on the suction side as most pumps are more efficient at pushing fluid than sucking it. It's hard to tell your overall hose routing from the pics, but unless you're able to remove a meaningful fluid restriction you're likely better off leaving it as is. Your PSC reservoir is dual return, correct?

I first thought the same thing but then did some research. Since I went from a smaller output on the reservoir to a larger hose, I think the pump has to work harder to "fill" the hose. I could be wrong.

Yes, it is dual return.

Some of it depends on how the adapter is shaped. If there is a very abrupt edge to it with a significant change in hose size or a number of size changes in a short distance, that can cause some pumping losses. I doubt it is causing all of your problem. I'd be tempted to pull the adapters and taper the inside edges where they transition into the larger hose. The goal is to maintain laminar flow, as the turbulence is what can screw things up. I'm guessing this is some of what you're getting at. You can reduce some of the turbulence while keeping the larger hose.

It's only one adapter.... -10AN Female to -12AN Male. Then the large 90 degree hose end.

Since my reservoir sits low, I think the pump has to pull a lot more since there is no gravity feed. Wouldn't a smaller hose make that easier? I've got it as high as it can possibly go (even notched the hood cross-member).

Think about trying to breathe through a straw. A big honkin' McDonald's straw is easier than a regular one (or a stir stick). There is a turbulent boundary layer of fluid where the it touches the hose wall, with an area of much more efficient laminar flow towards the center of the tube. More surface area for a given volume of fluid=more turbulence. You want to create as large an area of laminar flow as possible, given the constraints of the application and this can be done be decreasing the flow of fluid (making the boundary layer thinner) or increasing the size of the tubing, which has the same net effect (same thickness of boundary layer, but larger area of laminar flow). The 90 degree bend probably creates more turbulence and overall drag in the system than the change in hose size, and moving fluid more slowly through a larger diameter orifice (like your 12AN bend) will also help reduce turbulence. The difference in tube size between 12AN and 10AN is only 1/8", but there is a pretty significant difference in volume (~21 cu/in for 12AN vs. ~14 cu/in for 10AN in a 12" section of hose). The minor difference in the mass of the fluid doesn't really impact things given the amount of power that's turning the pump. Weight of the fluid involved only really becomes an issue over longer runs of larger diameter tubing. Then it's a matter of just applying more power to it, which won't net meaningful gains in a smaller volume system. The best way to get max flow is to reduce turbulence as much as possible. I doubt that having to pump up a little bit makes _that_ much difference, either.

You'd get the biggest benefit from finding a way to raise the reservoir. That might mean finding a different reservoir or moving it to the firewall.

If I am understanding your problem correctly, I seem to remember that all these hi-po steering pumps recommend you run as short and as straight a hose as possible into your pump. Hopefully drop straight down from the res into your pump. Seems your pump is starving for fluid.

http://www.pscmotorsports.com/pdf/tech/ ... r_tips.pdf

Can you rotate the reservoir to get rid of of the elbow?

Do you have room in this area of the firewall ?

image.jpg

2005 f250 Powerstroke.

What are your symptoms? Jerky steering? I'm afraid that moving the reservoir further away will make your problems worse.

I think you have a lack of volume/supply problem.

Have you called PSC?

From a reservoir volume perspective I think the PSC is bigger than OEM ?

Does the PSC res have a strainer in it ?

My guess is that the pump sucks all the volume from the hose and the long supply hose can't keep up. I don't think it's a total volume issue, just need better flow into the pump.

I wish there were an easy and cheap way to test this out. But everything I can think of will require some temporary rigging of the reservoir and making a shorter supply hose.

Let me email a buddy of mine I know that had supply issues and see what he ended up with.

After thinking about all your comments etc, I'm pretty sure I have to get it up higher. And that means mounting it where Rox has his on the firewall. The downside being 3 new lines and longer runs.

You could try a larger pulley on the pump too.

Do you think it possible to temporarily mount the res higher with your existing hose lengths and see if that helps? Even if you have to remove the hood...

I just want to be certain the proposed setup won't solve one problem, but create another yielding the same results.

My buddy is a machinist. I think he modified his reservior somehow and he might have a good solution for you that is cheaper than buying new lines??

Yeah, a pulley could help, especially at lower RPM's, but you'd want smaller correct?

In my work with hydraulics it was always a rule that 1) the inside diameter of the hose must be same or bigger than inside diameter of the fitting. 2) the straighter and smoother the path the better 3) the reservoir should be higher than the pump and lines 4) the return hose ID should be larger than the suction line ID to prevent back pressure. I have not dealt with this specific system but those rules should still apply. If the suction hose rises above the fluid level in the reservoir then air can be trapped in that area. Just my 2 cents

Sorry "return line should be larger than the pressure lines"

When I was designing my steering system I spent a lot of time on the phone with Howe. I chose Howe over PSC due to the recommendations of several racer friends who will not use free PSC parts vs. paying for Howe quality. Their words, I heeded them.

All recommendations I got were to run AN10 for the reservoir line, AN6 for the pressure lines and AN8 for the return side. That's how mine is and it works great. What size are your return lines?

I didn't see what you are running for the actual PS pump, but my $$ would be on a lack of volume/pressure from that pump to the HB/Braking system under "heavy" load. I personally would lean toward lack of volume. It's easy enough to adjust the pressure bypass of the pump creating higher pressure, but you have to rework the pump itself to get more volume out of it.

I do notice that your PS pump is upside-down. The output should come directly out the bottom, with the input near the top. Does it matter? IDK.

Based off the "verified hard pedal" do you have any cavitation bubbles visible in the reservoir?
HTH, Joe

The feed line is -10AN into a -12AN adapter and hose. Both return lines are -8AN. Pressure lines are -6AN.

Yes, it's a stock Explorer pump rebuilt and "enhanced" for higher pressure by Lee Power Steering in CA. They also installed a -6AN adapter on the pressure port.

Every time I have checked there are no bubbles in the reservoir.

Like Viper mentioned, I believe the pump is installed correctly.

I believe he meant that his racer friends would rather buy Howe parts vs PSC (even if they were free)