In Dire Need of Power Steering Pump Specs

[tmorgan4]

I tried to do my homework and search for specifications in the Factory Shop Manual but I'm unable to come up with anything besides the pressure. What I'm really looking to find is the maximum gallon per minute (GPM) or some comparable type of "flow" rating for the OEM power steering pump. I'm assuming that the models that A and T models may have higher flowing pumps than base models since they have larger hydraulic circuits (4-wheel steering or active suspension).

Any info would help me greatly!

Tyler

[tmorgan4]

Still looking....

[Infinitiguy19]

Is this on a pathfinder or a Q45, Hope Q45tech comes in and tells you because he know all that.

But I believe if you do some math, because (KG/CM2) is listed so just need to do some conversions.

[tmorgan4]

Appreciate the response. It is actually for the Pathfinder but as you may know I swapped a VH45 into it. I'm trying to find the flow specs on the OEM power steering pump to see if it will be adequate for a fully hydraulic steering system I've put in. I've got a power steering pump off of a larger 1-ton truck installed but it is giving me some issues and I was hoping I might be able to use the OEM pump instead. The Q45 appears to have a fairly hefty hydraulic system from the factory (4 wheel steering or active suspension) so I was thinking the OEM pump may have a larger output than pumps found in similar vehicles.

The specs you mentioned that are listed are the maximum operating pressure. It lists nothing about the maximum flow output (like a gallon-per-minute) specification.

I hope Q45 owners won't be reluctant to help me out since it isn't in a Q45.

[maxnix]

Well, let's start with which rack are you using and what is the output of that pump in pressure and flow rate?

[tmorgan4]

The "rack" I'm using is actually a ram. With the fully-hydraulic systems (often referred to as full-hydro in the 4x4 world) a double ended hydraulic ram with no mechanical steering connections is what turns the wheels. What you can't see in the picture is two hose connections (one for left, one for right).

Here's a poor picture of my current setup:

The specs on the pump I'm using currently fit somewhere in here. It's difficult to find the exact output as many different pump variations exist and many contain modifications to increase both the pressure as well as flow. This type of pump is commonly known as a P-pump and came from the factory in many larger 4x4 trucks and SUVs.



The pressure mentioned in the above spec sheet lists the P-pump at 1200-1300psi. According to the FSM, an OEM Q45 pump (without HICAS) lists a maximum pressure of 1109-1194psi. I'd imagine this should be sufficient and translates into how much force the ram can output to turn the tires.

As long as a Q45 pump could sufficiently flow 3.1-3.5GPM like the P-pump it would work perfectly. Does this seem like a reasonable number?

Thanks!

[maxnix]

Wow. So this ram system steers by positioning a piston with hydraulic pressure? I would assume flow rate is indeed critical if so.

I presume you cannot use the pump that normally powers it?
Modified by maxnix at 11:00 AM 10/15/2008

[tmorgan4]

Exactly....That shaft you see there is actually a single piece with a "divider" halfway between the two ends. There are basically two chambers inside that ram. When you want to steer left, the steering valve (connected to my steering column) sends high-pressure fluid into the right chamber which forces the shaft to move to the left. The pump I was currently using actually worked with the system very well. The "issues" that I was having with it were completely due to size and mounting position. The P-pumps are enormous and mounting it is not easy. Nobody makes a nice CNC'd bracket to put this pump on this engine.

[maxnix]

Ummmmm......big cooler. Way beyond me, but I bet the flow rate for the rack and pinion G50 pump is a whole lot less.