CBR Steering Pumps - OEM Applications?

[HYDRODYNAMIC]

Apparently no one lists high flow pumps specs. "Its a 1650, its a 1800, its a 1700 PSI HGH FLOW pump". Not Howe, not PSS, not PSC. At least PSC lists the CI/REV.
Most of the industrial vane pump manufactures all list a max rpm under 3000 so they are no help.

I called PSC to find out what they spec at:

"they are all in at 3000RPM and 6GPM"

Again I repeated "what does the non regulated pump flow"

"oh we don't know, because our test machine doesn't go that high"

"what does your machine max out at"

"it only goes to 10"

So I can only conclude that the pump is above 10GPM.

I called an old grey hair to find out if he has ever heard of a non regulated vane pump not putting out its full displacement. He confirmed the only way that can happen is for the pump to be restricted on the suction side and the pump is pulling a vacuum and creating a cavity as it rotates and closes back down. Basically cavitating, which should make the pump fail in a short while.
So RadialDynamics I don't believe that non regulated pumps are maxing out around 10PGM and cavitating around half of their displacement. I would believe 75% for efficiency lost due to a worn pump, but certainly not a new pump.

 

[Provience]

Here is my plan to externally regulate and pressure relieve the CBR XR race pump.
The Hydraforce FR12-33 has an inlet up to 30GPM and can flow up to 18 out the primary port and the rest bypasses to tank. The primary 18GPM can be turned down to 8 which I am guessing is a comfortable flow rate based on Eatons rating of 8GPM. The remainder of the flow will bypass to tank, which will vary based on pump rpm.
The RV10-26 is a pilot operated relief valve rated up to 30GPM
I am putting the RV10-26 in a cross port housing for plumbing purposes. The other housing port will have a FC10-20 which is being used as a plug. I already had it so that's why it is getting used. A check valve could also be used or a different housing.
The regulated bypass, relief, and return from the orbital will all go to the cooler and filter before returning.

trying to get a regulated priority flow valve was where i kept running into issues. there's surprisingly little support for non-OE uses what i could find was in the several hundred dollar range and my "ideal" setup turned into a ~$8k affair

Please toss an update somewhere with how that works out for you

 

[HYDRODYNAMIC]

trying to get a regulated priority flow valve was where i kept running into issues. there's surprisingly little support for non-OE uses what i could find was in the several hundred dollar range and my "ideal" setup turned into a ~$8k affair

Please toss an update somewhere with how that works out for you

If you want to do it on the cheap, look at the BRAND priority flow controls from Surplus Center. They are an adjustable pressure relief and set priority flow control in one cast iron housing. You pick what priority flow you want. I'm guessing a 8 GPM would be a safe one.

 

[RadialDynamics]

Hence the reason I measure the cam ring and rotor dims of every pump I get my hands on to calculate the displacement of different models. I use a variable orifice flow meter with a range of 0-32 GPM and have measured flow both on vehicle and on my test stand which uses a 22HP gas engine capable of driving pumps up to 5K RPM. When I first built my test stand with a 12HP 2 cylinder diesel, it bogged down and stalled trying to run a TT pump at pressure so I had to upgrade.

Just as a point of reference, I performed a monster truck steering evaluation last year on a brand new truck with brand new crank-driven gear pump (non-flow regulated). Some of the info is proprietary so I can't get into all of the specifics but starting off, their feed hose was too small. I measured flow rate on the truck from idle (1800 RPM) up to 4500 RPM and found that volumetric efficiency stayed right around 95% up to 2500 RPM. At 3500 RPM, that dropped to 90% and at 4500 RPM it dropped further to 70%. If we consider about 5% of that to be attributed to internal leakage, that would leave 25% of the cavity volumes filled with gas and causing cavitation.

Some changes to a proper hose size and plumbing arrangement got the 4500 RPM reading up to 88% efficiency but even with changes like that, decreasing efficiency at high RPM is going to be inevitable, it's just a matter of by how much. With the displacement of the XR pump that you have and based on what you have described sounding like you are setting it up correctly, I would not be surprised to see you hit at least 12 to 15 GPM max flow depending on specifics about your setup.

 

[HYDRODYNAMIC]

Plumbing has always been difficult. Bring in the high flow CBR, coolers, filters, valves and it becomes a mess as lines are too small and flow ratings are exceeded.
A common cooling and filter method with high flow piston pumps and motors is to run a hot oil flush where a small amount of oil is pulled from the closed loop and make up oil is added back in. There is no good way to filter 40gpm at 5000 PSI with a forward and reversing flow so a charge pump is used to filter and cool 20gpm at 250 psi. The circulation is still at a rate that can keep the oil clean and cool.
Now take into account many people are running no filter and low efficiency coolers and their pumps are surviving.
I do not have a flow path determined yet, but I think the same concept can be applied to lower the flow rates through the reservoir, filter, cooler, and lines.
With an external regulated pump it makes things easier as the flow is limited and split into two flow paths.
In an internally regulated pump only the priority flow makes its way out of the pump to the filter, cooler, reservoir, and lines. So 6gpm is very manageable. The remainder of the flow is sent right back to the intake.
To mimic this flow path with an external regulator. The priority flow at 6gpm is sent through the orbital then to the cooler, filter and reservoir where it restarts its path to the suction line. The bypassed and relieved oil now has a choice where to go. Since it is building heat it should go through a second cooler or possibly the main cooler. It don't think it needs to make its way through the filter and reservoir as this is already being covered by the priority flow circuit. The bypassed oil now cooled can be sent back into the suction. This allows for a smaller reservoir and filter assembly and lines.
I will continue to figure out what this flow path looks like.

 

[Provience]

If you want to do it on the cheap, look at the BRAND priority flow controls from Surplus Center. They are an adjustable pressure relief and set priority flow control in one cast iron housing. You pick what priority flow you want. I'm guessing a 8 GPM would be a safe one.

seemed like when i was looking around a year or so ago i kept getting stumped trying to find something that would keep the priority flow at or near static. i.e. 8gpm, if the input flow is 6 gpm, then 100% to the priority side, if the input is 10 gpm, then 80% to the priority side.

All the cheaper ones that i found were a static split or a split up to a limit, i.e. 6 gpm input = 3gpm priority/3 excess, 20 gpm input= 8 gpm priority/12 gpm excess.

FG-REV(D)-2018.pdf (brand-hyd.com)

but maybe the FG series is what i had been hunting for.

The priority port will maintain the same flow setting even with an increase or decrease in the input flow.

I know Zag had a local priority flow valve made up from a local shop that did it well and he was happy to have added it to his system, but he already had a full system so it was easier to spec something that would work.

 

[gozuki]

Hydro and/or Radial, would you address the pros and cons of the second image, TG's integrated reservoir/filter?

 

[HYDRODYNAMIC]

Hydro and/or Radial, would you address the pros and cons of the second image, TG's integrated reservoir/filter?

First of all have fun changing that filter. It’s going to dump oil everywhere.
Second, it’s a huge brick that will take up real estate and add weight.
Third, I am guessing that the reservoir is just a tube welded on the brick with no designed flow path.
Fourth, it looks like it has too small of fittings.

 

[RadialDynamics]

First of all have fun changing that filter. It’s going to dump oil everywhere.
Second, it’s a huge brick that will take up real estate and add weight.
Third, I am guessing that the reservoir is just a tube welded on the brick with no designed flow path.
Fourth, it looks like it has too small of fittings.

This. Similar to all of the other combo filter/reservoirs, there is no flow path through the reservoir canister so the fluid in there is stagnant and air will not have a chance to evacuate out of the steering fluid so long as the engine is running.

Two additional problems though, not only will you dump oil when you go to change the filter because it's upside down but also it will be a place to trap an air pocket. Throughout the rest of the system there are local peaks that air pockets could form but we rely on flow velocity to carry air back to the reservoir to be removed (hence why plumbing should have a minimum as well as maximum flow velocity). But in the filter canister, flow velocity is lower so it is going to be more difficult to bleed the system when you change that filter out. The other issue is that reservoir cap is completely sealed. I use radiator caps on my reservoirs to build pressure as the fluid heats and expands which is a big help in reducing cavitation but with a radiator cap, it will vent air to limit max pressure. With a sealed cap, there is no control over how much pressure could build up in the res and over 20 PSI, there is risk of damaging or pushing the shaft seal out of the front of the pump.

 

[AgitatedPancake]

More awesome tech. Which leads me to a few more questions haha.

On the subject of filtration: Understanding those Beta ratios is extremely eye opening. Beta 2, Beta 75, Beta 1000 seem to be the references I've seen most so far, and genuinely provides an accurate filter efficiency number to allow comparing apples to apples (when the same Beta measurements are available on the different filters you're looking at). That donaldson is badass at 1 micron Beta 2 rating versus the lowest I've seen from others like Parker being 3 micron Beta 2.
Donaldson P551324: https://shop.donaldson.com/store/car...ils-DCI.jsp.1#
Parker spin on filters: https://www.parker.com/literature/EM..._12AT_50AT.pdf


I seem to see two different thought processes from you guys on reservoirs and now it has me curious enough to expand further. Radial, your thought process seems to align with what I've mostly seen over the years where it's ideal to have a cylindrical reservoir and run the returning fluid into the reservoir radially to run it along as much surface area of the inner wall as possible in a minimal turbulence vortex to de-aerate the oil before funneling it into the suction side of the pump. One example of a reservoir I've always seen that seemed like it had a lot of thought put into it is the woodward one from the below catalog. This seems like it works exceptionally, then you just run a massive feed line to the suction side of the pump to make sure it sees minimum vacuum possible under high flow conditions. But then Hydro, you have noted a few times the idea of supercharging the intake. Which due to this thread, I now understand is what was going on in the large return line of the grand cherokee hydro fan reservoir configuration. Where in concept, you use the velocity of the returning fluid directed right at the suction side of the pump to apply inlet pressure/avoid vacuum on the inlet side of the pump. The benefit of that seemingly makes sense now, with the downside that it's nearly cycling as a closed system, and not using much/any of the reservoir volume beyond what's directly in the flow path. So you have less volume to absorb heat (which can be mitigated with sufficient cooling), but more importantly no chance for air to escape the oil being circulated. If you subscribe to the latter theory, is there any way to efficiently extract potential air elsewhere in the system?

Both of these also lead me to a further curiosity - how little fluid volume can you really get away with? If you have proper cooling and flitration, it seems like you can keep it pretty minimal (while understanding fluid breakdown will probably happen faster just due to smaller volume being used). The scenario I'm using is actually my own right now. As you guys know I'm still getting my system dialed in, but I'm OK with experimenting. I'm running the stock jeep reservoir, so it's got a capacity of a bit less than a quart beyond what's in the rest of the system. Going to a jeep (Delphi 600) steering box, and also feeding a 2.5" x 8" double ended ram. The res is very good at keeping the inlet submerged, and has the return fitting aiming directly at the pump inlet. So it's nearly a closed loop, with the reservoir volume available for expansion and contraction. But because my assist ram is balanced, the rise and fall in fluid level is no more than just the factory steering box does. I plan to keep the fluid cool, and add filtration, then see what happens. Curious to hear your thoughts and will put a gallon under the hood if I have to, but it would sure be sweet to avoid.

Woodward catalog mentioned above:
http://www.woodwardsteering.com/PDF/...Components.pdf

Screenshot of the reservoir in the catalog just to make sure it doesn't disappear on us later down the road:

On the subject of these aftermarket flow control valves with integrated pressure relief essentially the exact operation happening inside our steering box (*edit* meant steering *pump*)? For the reasons hydro noted, if you were to make that operation happen externally (but operate the same), you could feed the bypassed fluid through a cooler which would be awesome. I see the steering box setups called "pressure compensated flow control valves", and from reading the PDFs of those valves you guys shared it hasn't quite clicked for me yet if it's the exact same operation.

I did stumble upon this 3 part youtube video which really helped me observe what's going on in the steering box flow controls:
https://www.youtube.com/watch?v=mCPJ...nchBoxSessions
https://www.youtube.com/watch?v=elg3...nchBoxSessions
https://www.youtube.com/watch?v=L2Fj...nchBoxSessions

 

[RadialDynamics]

I've done enough flow path testing within an acrylic reservoir model to see that typically, what looks like it will work on paper will look totally different when you start putting flow through it. When I started on my Vortex Reservoir design, what I ended up with in the end that worked was completely the opposite of what I thought my design would look like at the beginning.

In terms of the cyclone design above, air wants to pull towards the very center of rotation. If flow has to go around a large internal cylindrical baffle like that then the air bubbles will travel both up and down and as soon as they reach the perforated portion of the baffle, they are heading in towards the center. The center of a reservoir with cyclone flow is where the lowest pressure is so having the outlet to the pump in the very center of a cyclone flow path is the worst place for it.

Supercharging the pump feed is good but the term "supercharge" simply means to pressurize above atmospheric pressure. With the previous designs others have discussed, this occurs because you essentially create a jet pump with the return flow but as noted, the volume in the reservoir is stagnant. However, toss a 10 PSI radiator cap on your reservoir and now as soon as the fluid starts to rise temperature, it is expanding and building pressure and at that point, the pump feed is technically supercharged. With my Vortex design, you not only get the benefit of a supercharged pump feed (both from the radiator cap and the tangential outlet port) but also 100% circulation of internal volume, forced de-aeration, and pump feed that keeps air out at extreme off-camber angles.

 

[Provience]

More awesome tech. Which leads me to a few more questions haha.

On the subject of filtration: Understanding those Beta ratios is extremely eye opening. Beta 2, Beta 75, Beta 1000 seem to be the references I've seen most so far, and genuinely provides an accurate filter efficiency number to allow comparing apples to apples (when the same Beta measurements are available on the different filters you're looking at). That donaldson is badass at 1 micron Beta 2 rating versus the lowest I've seen from others like Parker being 3 micron Beta 2.
Donaldson P551324: https://shop.donaldson.com/store/car...ils-DCI.jsp.1#
Parker spin on filters: https://www.parker.com/literature/EM..._12AT_50AT.pdf

on filtration, i have a note that says "pump wants 10 micron, everything else 15-30 micron" and probably referencing a gear pump as "pump" and everything else would be cylinders and valves. most everything is the system is pretty tolerant to debris.

does anything beyond beta 20 (90%) for 10 micron matter? I dunno. sure, more is always better and such. most OEM (automotive) systems use a screen and that (likely) does more for de-aeration than it does for debris.

filters are good and worthwhile

Understanding Beta Ratings of Liquid Filters | Donaldson Engine & Vehicle

 

[RadialDynamics]

On the subject of these aftermarket flow control valves with integrated pressure relief essentially the exact operation happening inside our steering box? For the reasons hydro noted, if you were to make that operation happen externally (but operate the same), you could feed the bypassed fluid through a cooler which would be awesome. I see the steering box setups called "pressure compensated flow control valves", and from reading the PDFs of those valves you guys shared it hasn't quite clicked for me yet if it's the exact same operation.

They are essentially performing the same function as the valving in a steering pump, not a steering box. The difference is in a steering pump with internal valving, the excess flow above the priority setpoint is forced back into the pump inlet where on most pumps, it further helps supercharge the incoming flow from the reservoir. If you pull that function out to an external valve, you either let the excess flow go back to the reservoir and now you have that much more flow that needs to make its way from the res to pump at high RPM or you can feed it directly back to the pump through a second inlet but there is only one pump I can think of with more than one inlet port.

Sure, you can feed that excess flow through a cooler and filter but if you are talking about keeping the priority and excess flow paths separate, are you now talking about running two coolers and two filters, that much more plumbing and that many more potential leak points? Again, not that what is being proposed is a bad thing but when the most recent KOH winner with the largest displacement pump available is operating as reliable as possible with an internally flow regulated pump (and externally pressure relieved), I will simply ask, is all that extra equipment necessary?

 

[RadialDynamics]

on filtration, i have a note that says "pump wants 10 micron, everything else 15-30 micron" and probably referencing a gear pump as "pump" and everything else would be cylinders and valves. most everything is the system is pretty tolerant to debris.

does anything beyond beta 20 (90%) for 10 micron matter? I dunno. sure, more is always better and such. most OEM (automotive) systems use a screen and that (likely) does more for de-aeration than it does for debris.

filters are good and worthwhile

Understanding Beta Ratings of Liquid Filters | Donaldson Engine & Vehicle

https://www.mobil.com/industrial/~/...er-oil-cleanliness-in-lubrication-systems.pdf

ISO4406 is where recommendations for Beta1000 limits come from and you can find those in this PDF

 

[Provience]

https://www.mobil.com/industrial/~/m...on-systems.pdf

ISO4406 is where recommendations for Beta1000 limits come from and you can find those in this PDF

from that chart

Fixed vane pump under 2K PSI tolerates measuring 20/18/15 for 4/6/14 micron particles and wants a Beta 1000 of 22 micron filtering media



Donaldson Blue Hydraulic Filter Cartridge - DBH6019 – Donaldson Filters (dieselequipmentinc.com)

gah darn, trying to find and sort filters by size and efficiency is suprisingly difficult just trying to get a rough idea, anyways, here is a B1000 10 micron rated for ~$60

yeah yeah, i know i'm recreating a bunch of the work that you've already done. hence why people should just buy things and save the time. i'm just curious enough to attempt to independently verify




edit: Engine and Industrial Air, Oil and Liquid Filtration | Donaldson Company, Inc.

the donaldson "shop here" website -> attribute search -> hydraulic filters -> beta 1000 rating -> 20 micron +/-2 or use 10 micron or whatever...that is actually an easy and reliable way to search for a part number


edit2: now it makes sense why the B1000 23 micron filters are more "common"...they can be had in ~3-4" lengths for <$40 all day long while 22 or 12 or 10 micron filters at that same level are larger or near double the price.

 

[HYDRODYNAMIC]

Within the realm of hydraulics, supercharging means force induction to the pump. In order to do that the pump must pump back to itself. Enter the chicken vs egg, which came first. This is easier to think of how axial piston pumps and motors work in a hydrostatic closed loop system. A separate charge pump creates a low pressure to feed the closed loop on both sides of the pump (high and low pressure sides) and the pistons in the high pressure pump are pushing oil through the pistons in the motor and then returning to the low pressure side of the pistons in the pump to repeat the process. There is no being and end. They are like fluid gears tooth to tooth. This is how the hydrostatic pumps can reverse direction instantly. There is no air space to collapse.
In order to run a steering system in what resembles a closed loop supercharged flow path, the reservoir needs to be at a high point so the air can flow up and the oil can replace it. This is done at initial purging of the system and at low idle low flow and shut down to rest and let foam turn to bubbles and then started back up to continue purging. Once the system is purged of the air it’s gone as long as the reservoir does not mix air back into the oil. Keeping the reservoir 100% full and using a overflow catch can further reduce air from entering the system.
Now that the system is void of air, there is nothing to collapse. The pressure lines are now pushing oil through the filter, cooler, and valves under force and pushing it into the suction of the pump.
To compare a traditional reservoir with open loop. The pump pushes oil through the filter, cooler, valves and dumps into a tank. The oil looses its velocity as it dumps into the tank and energy is lost and turned into heat. The pump spins and suction or low pressure pulls oil out of the reservoir and can create cavitation and vacuum. The velocity and energy from the return lines is not there to keep pushing along the oil to the suction of the pump.

 

[HYDRODYNAMIC]

Too much obsessing over filtration. How many OEM pumps run filters? Are they blowing up all over the road side? When you have clean oil and you are filtering all the time, the oil stays clean. You do not need to capture a huge dump of debris in one pass. If you do then you have bigger problems.
Filters are mainly working during start up because the lines and parts were not cleaned properly or during filling with a dirty container.
More importantly make sure the filter can flow enough. The PSC WIX 51088 is good for 9 GPM and has a 30 psi bypass. Knowing this I am not going to filter 100% of the pump flow. Only the regulated flow somewhere around 8 GPM.

 

[AgitatedPancake]

Interesting notes from both of you - separate trains of thoughts, and both seem to work. I believe I'm seeing the ups and downs of both options. My current config is essentially following the supercharged method due to the stock reservoir return placement, so I'll be able to review it in the longer term to decide if improvement is needed. I am planning at least some sort of filtration though, just for peace of mind.

Now I have another thought - because my reservoir has a second return available that's up away from flow, I'm almost thinking about putting a fitting with a tiny orofice (Less than 1/8") at the top of the lower pressure side of a filter assembly where the fluid velocity is the lowest, and air would have the highest chance to escape. That fitting would have a line that leads back to the top reservoir return. that allows a very small amount of return just to de-aerate the fluid from the best potential spot and agitate the res. So the supercharged side would be pushing 95% of the fluid into the pump inlet, and would pull the remaining volume from the nearly stagnant reservoir volume. Slightly more restriction than it has now - too much?

 

[HYDRODYNAMIC]

While figuring out a flow path I ran into the issue of having to split the flow since the cooler can handle full flow 18+GPM but the filter can not at 9 GPM.
As much as I like PSC I wasn’t going to compromise to stay with their filter combo which I believe is correctly sized for an internally regulated CBR.
I started researching other trophy truck size filter reservoirs and ended up at Kartek, taking them apart and looking at the flow path and filter size. I found a Howe 4” x 6” filter reservoir with a 15GPM filter and larger internal ports. Design wise it’s a big brother to the PSC. The added benefit that I wanted was a radiator relief cap and vent port which makes catch can attachment much easier.
Being able to run full flow allows everything to be filtered, cooled, and de aerated. I don’t have to split the flow. While I very well might add a priority flow control, I’m going to hold off until proven that the high flow is too much. I keep forgetting that I wanted a mainstream buggy, simple and proven even if it can be done better.

 

[HYDRODYNAMIC]

There is an internal baffle around 2” from the top.

 

[RadialDynamics]

While figuring out a flow path I ran into the issue of having to split the flow since the cooler can handle full flow 20 GPM but the filter can not at 9 GPM.
As much as I like PSC I wasn’t going to compromise to stay with their filter combo which I believe is correctly sized for an internally regulated CBR.
I started researching other trophy truck size filter reservoirs and ended up at Kartek, taking them apart and looking at the flow path and filter size. I found a Howe 4” x 6” filter reservoir with a 20 GPM filter and larger internal ports. Design wise it’s a big brother to the PSC. The added benefit that I wanted was a radiator relief cap and vent port which makes catch can attachment much easier.
Being able to run full flow allows everything to be filtered, cooled, and de aerated. I don’t have to split the flow. While I very well might add a priority flow control, I’m going to hold off until proven that the high flow is too much. I keep forgetting that I wanted a mainstream buggy, simple and proven even if it can be done better.

Hydro, we should talk. That is actually the particular reservoir that led me down the path of reservoir development and re-engineering the full hydro systems with TT pumps. That Baldwin filter is rated for 12-16 GPM so you will already be pushing its flow limits when it's clean and you still won't circulate the fluid up in the canister.

Here is the system layout that I think you should take a look at with my 25 GPM filter and integrated external relief valve, high flow cooler, and de-aerating reservoir. When it comes to extreme angles, if you watched Josh Blyler land on his roof for 5 minutes just before winning this past KOH, he had this reservoir in there that didn't miss a beat as soon as he was righted and fired back up. I think you would be quite pleased with this setup.

 

[HYDRODYNAMIC]

I have seen both 20 GPM and 12-16 GPM for that filter. I figure it comes down to flow port size which is at .75” which according to the hose chart lines up .75” @ 15GPM @ pressure line velocity. Yet most of the reservoirs are running -12 fittings with a .625 port size and .75” hose for suction when they should be -16 or -20.
I will probably use -12ORB to -16 JIC fittings and -16 hose for suction and drill out the -12 fittings to .75 to increase flow.

 

[gozuki]

I have seen both 20 GPM and 12-16 GPM for that filter. I figure it comes down to flow port size which is at .75” which according to the hose chart lines up .75” @ 15GPM @ pressure line velocity. Yet most of the reservoirs are running -12 fittings with a .625 port size and .75” hose for suction when they should be -16 or -20.
I will probably use -12ORB to -16 JIC fittings and -16 hose for suction and drill out the -12 fittings to .75 to increase flow.

Are you using the Howe reservoir pictured?

 

[AgitatedPancake]

So I'm curious enough to do a little more studying at this point, I want to see what my current flow rate is at idle, at 1k rpms, 1500 rpms, and then something like 2000 RPMS to create some data points and see where the flow/rpm curve flattens out with this 5/32" fitting and the stock 5.5" pulley. A little more complicated because I need to measure out the steering box piston diameter and throw to add it's displacement to the ram volume when timing lock to lock steering time, but then I'll be ready to move ahead. Right now it feels like it's probably somewhere between 1,000-1,500 just based on the test driving I've done since putting the pump back on, but want to specifically figure that out. Then the plan is to step to a 4.5" pulley, at which point i should be able to calculate the new engine RPMS of the flow cutoff (but may check anyways to confirm). Then if cutoff comes in too near idle, I'm considering opening the orofice in small increments to raise the cutoff rpm back up toward 1500 RPMs.

Just a very fluid goal as I note my experiences in more detail, and further develop my understanding of what I actually like the steering to feel like. But it should be a pretty fun process, as all of this learning has been.

 

[Fwjeep]

So I'm curious enough to do a little more studying at this point, I want to see what my current flow rate is at idle, at 1k rpms, 1500 rpms, and then something like 2000 RPMS to create some data points and see where the flow/rpm curve flattens out with this 5/32" fitting and the stock 5.5" pulley. A little more complicated because I need to measure out the steering box piston diameter and throw to add it's displacement to the ram volume when timing lock to lock steering time.

If it’s a stock Saginaw steering box, from a smaller vehicle, s10,jeeps,Astro, it measures 2.75 in diameter, and with steering stops in the box at maximum, 3” of travel, and that is 90 degrees of pitman arm travel. 17.1 cu in lock to lock.

the bigger style boxes, Durango snow plow, Chevy pickups, Chevy vans, are 3.25 pistons, which have the same travel numbers. 24.9 cu in lock to lock, also max 3” travel.

 

[AgitatedPancake]

If it’s a stock Saginaw steering box, from a smaller vehicle, s10,jeeps,Astro, it measures 2.75 in diameter, and with steering stops in the box at maximum, 3” of travel, and that is 90 degrees of pitman arm travel. 17.1 cu in lock to lock.

the bigger style boxes, Durango snow plow, Chevy pickups, Chevy vans, are 3.25 pistons, which have the same travel numbers. 24.9 cu in lock to lock, also max 3” travel.

Unfortunately when they went to the WJ model, they swapped over to a new version of steering boxes that have a long sector shaft and put the cylinder up above the frame rail. It seems to be called a "Delphi 600" box in the hotrod scene. It's not a bad setup and i've rebuilt a few, but admittedly do not recall piston diameter or throw hehe. I may use those saginaw numbers for reference as a filler in the meantime though, so the numbers are appreciated.

 

[RadialDynamics]

If you are trying to back-calculate your flow rate based on the lock to lock time and displacement of your steering box and assist ram, I would be suspect of the numbers that you end up with mainly for the reason that unlike in a full hydro system, a steering box is going to be limited in terms of how fast it will let fluid into the cylinders so there will almost always be some portion of flow passing through open center of the rotary valve. It wouldn't take much open center flow or tolerance in your lock to lock time measurements to make your numbers significantly inaccurate and when dealing with a pump that is likely only putting out 3 to 4 GPM max, a flow meter is really the only way to get an accurate measurement of pump flow vs. RPM.

 

[AgitatedPancake]

If you are trying to back-calculate your flow rate based on the lock to lock time and displacement of your steering box and assist ram, I would be suspect of the numbers that you end up with mainly for the reason that unlike in a full hydro system, a steering box is going to be limited in terms of how fast it will let fluid into the cylinders so there will almost always be some portion of flow passing through open center of the rotary valve. It wouldn't take much open center flow or tolerance in your lock to lock time measurements to make your numbers significantly inaccurate and when dealing with a pump that is likely only putting out 3 to 4 GPM max, a flow meter is really the only way to get an accurate measurement of pump flow vs. RPM.

Interesting, but makes sense. The degrees of twist in the torsion bar dictate how far the servo is open, so unless I can guarantee I'm against the stops for the entirety of the test, there's no way to be truly consistent. And anything less than full twist is bypassing fluid through the return (maybe even bypassing some at full torsion?) It would be interesting to see the observed numbers versus some theoretical numbers based on some of the TC pump displacement numbers thrown around in this thread, and find out how much of the flow could potentially be purged through the relief.

But in reality, my intent is less about finding accurate pump flow numbers through this process than it is observing the relationship between the flow valve opening and engine idle RPM. The relationship between those two has become of particular interest to me, as I figure out what really makes the steering characteristics we take for granted in stock vehicles

 

[Fwjeep]

Unfortunately when they went to the WJ model, they swapped over to a new version of steering boxes that have a long sector shaft and put the cylinder up above the frame rail. It seems to be called a "Delphi 600" box in the hotrod scene. It's not a bad setup and i've rebuilt a few, but admittedly do not recall piston diameter or throw hehe. I may use those saginaw numbers for reference as a filler in the meantime though, so the numbers are appreciated.

Your right, they switched to metric Delphi 600 boxes on the wj, and the jk is just the reverse swing of it.
it is a 70mm piston, and travels 78mm. It displaces 17.1 cu in of fluid lock to lock.
ive had jk and wj boxes apart. There are some differences, from the origanal Saginaw box. The sector shafts between boxes fit, pistons same sizes, but the servo is different.
mu research to do a de-powered steering box, koh 4500 class style steering. These Delphi boxes work good for that, and the piston/sector shaft void can be completely isolated from pressurized fluid. However, I have not been able to find new torsion bar sizes.

a very ported Saginaw box can flow more then 12gpm, with 150 neutral psi

 

[AgitatedPancake]

Your right, they switched to metric Delphi 600 boxes on the wj, and the jk is just the reverse swing of it.
it is a 70mm piston, and travels 78mm. It displaces 17.1 cu in of fluid lock to lock.
ive had jk and wj boxes apart. There are some differences, from the origanal Saginaw box. The sector shafts between boxes fit, pistons same sizes, but the servo is different.
mu research to do a de-powered steering box, koh 4500 class style steering. These Delphi boxes work good for that, and the piston/sector shaft void can be completely isolated from pressurized fluid. However, I have not been able to find new torsion bar sizes.

a very ported Saginaw box can flow more then 12gpm, with 150 neutral psi

Solid info, thanks a ton for that. Interesting the similarities between these and saginaw displacement wise, I wouldn't have guessed! Having the servo section seperate on this style box with passages that can be blocked is definitely nice if de-powering the box. In the long term if I decide I want faster steering, I've considered de powering the steering box and increasing the pump PSI to decrease the volume needed but try to minimize force loss.

My 2.5x8 ram with 1.5" shaft has 25.12 cu in, then using your numbers I also have 17.1 cu in of box volume. So lock to lock requires 42.22 cu/in. If I want to be able to cycle from lock to lock in say 2 seconds, I need the pump to flow about 5.5 GPM, and get that much through the box. If my pump is .69 cu/in displacement, that's 1,850 pump rpm assuming 100% efficiency. so I would need the pump spinning over 2:1 to crank speed to acheive that anywhere near idle. That's asking a lot from at least these small pumps. If I de-powered the steering box the ram would only require 3.25 GPM to go lock to lock in 2 seconds which would be around 1,100 pump RPM, far more acheivable.

When you say a very ported saginaw can flow 12 GPM that's crazy. Is that just how much it can freely bypass with that super low neutral pressure, or is that how much it can actually use and send some downstream for assist uses? Is that just porting of the box passages, or is that opening up the servo orofices as well? It would be awesome to add the hydro assist plumbing directly to the servo on these delphi 600 boxes, but I haven't experimented (or seen tested) yet. I have a spare steering box, maybe I should do some investigative disassembly and see how much potential there is to get things flowing more easily.