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CBR Steering Pumps - OEM Applications?

I am not sure how the "needle" is attached to the spool valve. I didn't want to grab on to either part and damage them.
 
The more I dive into this pump the more it seems like it should be operating just like we want. When the spool valve is fully seated against the output fitting, the necked down portion of the needle is through the output fitting orifice. This results in a huge orifice by previous standards with a net area of 0.035 sqin or an equivalent orifice diameter of 0.21" (ignoring geometric differentces). As the spool valve shifts away from the outlet the increased head dia will enter the orifice in the output fitting resulting in a net area of 0.023sqin or and equivalent orifice diameter of 0.171" which is just slightly larger then traditional drill size of 5/32". Past that I assume the pump would be in full bypass.

So that leads me to believe that I have something else wrong. Suction hose collapsing being my first item to check.

Spool Valve.jpg


end view.jpg
 
are you using the same pulley on this as you were on your TC pump? slower steering at speed or slower steering at idle?
 
The TC does have a smaller pully at 4.5" with a crank pully of 5.5. The cbr has a 5.375 pulley with a crank pully of 6.375. So the ratios are pretty close.

The steering feels slow at speed and at idle. I'm about 5 seconds lock to lock stationary at idle.
 
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Starting to wonder if there is something different about the pump due to a diesels RPM range. Going to see if I can get my hands on the gas version.
 
Man I'm intrigued by that device on the flow control valve. It seems like the intent is to vary the orifice diameter depending on certain conditions, but I haven't quite wrapped my head around it yet. Interesting note on the diesel RPM range, but I'd be surprised if there is a notable difference (beyond whatever this device is, maybe this is the cause). 5 seconds lock to lock is pretty slow, so something does seem interesting all around. Although I will note that your crank pulley diameter vs PS pulley diameter leaves a lot to be desired to get the pump spinning at decent RPMs. If you haven't already, check out that steering calculator I made a while back plug in your numbers and see if the steering lock to lock times seem to coincide with what you're getting
 
Very nice. Just for grins, what's your steering setup - 2.5x8" full hydro?

*edit* and also, what are your engine RPMs at idle?
 
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Nice, do you happen to have any pics of your reservoir location (and what style res?)

Just for grins I plugged your numbers into the calc. Looks like with a 500rpm engine idle you'd have around 4 seconds lock to lock with the smallest displacement CBR that's been seen. But you probably idle higher than 500, and are noting slower than 4 seconds so there's definitely a discrepancy (bottleneck) somewhere in your system causing you to achieve less volume than the pump should actually be producing. Related question - is the pump running quiet?

MtnYota PS numbers.jpg - Click image for larger version Name: MtnYota PS numbers.jpg Views: 0 Size: 270.1 KB ID: 358942
 
Ya, I’ve heard that. I’ve really grown to not like the way PSC does business. I bought the whole kit from PSC. After I installed it, they told me I need to run -8 pressure and return lines. To which I responded, “then why doesn’t your kit come that way.” The answer was “ it’s not that expensive to buy the -8 fittings and hoses.” Which is part of my motivation to useing and oem pump.

Anyways, enough bitching. My Toyota has the same size lines with a PSC TC pump and doesn’t have an issue. The -10 suction hose is 4” long verses 12” with a sweeping 90 on the explorer. I’ll check the flowrate as is, and after if i end up swapping it out. I do see on the flow/line size/velocity chart posted earlier that the return is outside the recommended hose velocity.

Idle seems to be about 800-900rpm and lock to lock is between 4-5sec.
 
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MtnYota said:
I do see on the flow/line size/velocity chart posted earlier that the return is outside the recommended hose velocity.
Click to expand...

That's what I was going to mention. Usually return is higher ID than the feed.
 
Restriction in the return side should just decrease power available by creating more backpressure, but the volume should be good still. Example: 1200psi available out of the pump, but 200psi backpressure on the return side of the system only gives you an 1000psi pressure differential providing force in your ram. The fixed displacement pump still should be pushing the same amount of volume though (at whatever volumetric efficiency it has, and assuming no cavitation)
 
Just did a quick test at idle and it’s flowing a consistent 3gpm with zero psi showing on the test gauge. After I get the kids to bed I’ll test some more scenarios. Right in line with AgitatedPancakes spreadsheet.
 
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MtnYota said:
Just did a quick test at idle and it’s flowing a consistent 3gpm with zero psi showing on the test gauge. After I get the kids to bed I’ll test some more scenarios. Right in line with AgitatedPancakes spreadsheet.
Click to expand...

interesting that at 3gpm it is showing zero psi. i'm assuming you are measuring right at the pump outlet?

what style of flow meter are you using? :)
 
Here are two videos. The first is with no steering input. Just revving the engine.
https://www.youtube.com/watch?v=yXlbolYOcHY

The second is turning lock to lock at idle, 1000rpm, and 2000 rpm. If you look at 2 o'clock position from the gauge you can see the steering shaft turn, which is helpfull in determining what is going on.
https://www.youtube.com/watch?v=MtVj5JeJOKk

Pressure relief is set at 1600psi. Flow appears to drop to almost nothing once I hit the stops. Turning pressure to turn the 40" TSL on concrete pavers 600-700psi. Flow seems to stay steady at 3 gpm.

Let me know if you guys see anything that I'm not. And I don't want to hear anything about my video skills:flipoff2:
 
it's funny on the second video, you can see the flow quickly jump up to about 5 gpm as soon as you let off and the pressure drops down, just a slight slight "reaction" delay to the control valve from full bypass to full control

really appreciate the videos. i'm kind of surprised the flow control valve is limited to 3gpm, figured it would be set higher than that.

where do you think the best area to relieve the valve at would be to increase flow before bypass?
 
Hmmm interesting videos all around. As Provience noted, it looks like your flow control is set somewhere around 3gpm which you're hitting at pretty low RPM. I still don't fully grasp the added complication of the "needle valve" in the flow control though. It does look like your pressure spikes to around ~1600psi noting what happens when you hit the stops. One weird thing - in the second video from 0:35-0:43 seconds, why is there pressure? Were you holding your hands on the wheel, maybe against lock? It's the only instance where you're reading pressure while not providing any steering input
 
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AgitatedPancake said:
Hmmm interesting videos all around. As Provience noted, it looks like your flow control is set somewhere around 3gpm which you're hitting at pretty low RPM. I still don't fully grasp the added complication of the "needle valve" in the flow control though. It does look like your pressure spikes to around ~1600rpm noting what happens when you hit the stops. One weird thing - in the second video from 0:35-0:43 seconds, why is there pressure? Were you holding your hands on the wheel, maybe against lock? It's the only instance where you're reading pressure while not providing any steering input
Click to expand...

should be holding against lock, nowhere for the fluid to go except for bypass
 
I must have had some partial pressure against full lock.

I am strongly thinking that I need to open up the pilot circuit port dia. If my understanding of how the valve is working is correct.

At a low flow situation, the pressure on each side of the piston is the same due to the pilot circuit. But as the flow increases the fluid velocity across the pilot port creates a pressure drop in the pilot circuit. (Think blowing across the soda straw) This pressure drop creates a lower pressure on the back side of the spool valve that is balanced by the spring. As flow velocity increases the pressure drop get high enough to overcome the spring preload and the spool valve moves back.

So by opening up the pilot circuit port it should cause the bypass point to occur at a higher flow rate.

That is unless I am wrong. Because opening up the output orifice would have the same effect. Larger port results in lower fluid velocity, but my port is already fairly large.
 
Yeah hands on the wheel was my guess too, at least it's one explanation that makes sense haha.

If you have another pump around, I'd be tempted to swap that spool valve and pressure fitting with a more standard setup. so you can confidently drill the output fitting orofice to something known like 11/64ths for somewhere in the 3.75-4gpm range iirc. You can drill this output fitting out as well for similar effects, but partially stepping into the unknown because we don't quite understand this additional device yet.

But no modification to the flow control system will help your speed at idle, as I believe your max flow point is above idle (so idle should be getting full flow). Though there is still one discrepancy - even now at 3GPM with a 2.5"x8" ram you should be able to get ~2 second lock to lock which is silly quick. That means your 4 second+ lock to lock is only getting 1.5GPM. The question there is why is that so much lower than expected? Is your orbital acting normal overall?
 
I've been slowly collecting parts to have fun with myself, interesting to observe differences. Left pump is an aluminum WJ hydro fan TC pump with steel spool valve. Middle is a steel WJ hydro fan TC pump with aluminum spool valve (same length though), and far right is a larger CB pump which uses a longer steel spool valve. No specific observation here, just bringing a pic for the sake of tech
165321760_302006134599448_1984722114060398787_n.jpg
 
I have a couple of stock pumps that I could see if they are similar enough to drop in. One being the stock tc pump off a 97 4runner and the second is the stock explorer pump. Which I found a video yesterday an it's the only other pump I've seen with a "needle" on the spool valve. https://www.youtube.com/watch?v=hDy8JXbPA9U&t=184s

I may try and pull apart the PSC tc pump on the toyota and see if I can swap those spool valve and output fitting into the cbr pump.
 
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AgitatedPancake said:
Though there is still one discrepancy - even now at 3GPM with a 2.5"x8" ram you should be able to get ~2 second lock to lock which is silly quick. That means your 4 second+ lock to lock is only getting 1.5GPM. The question there is why is that so much lower than expected? Is your orbital acting normal overall?
Click to expand...

This is the part that is bothering me. I rotated the ram so the fittings point straight up. Jacked the tires off the ground and cycled the steering with the the engine off 10 times. Then I started it and cycled it with the tires still in the air. The time was in about the 3.5seconds range and about the same once I set the tires back down. That doesn't seem right.

Steering valve is a new Eaton unit, so not that it couldn't have an issue but I would be surprised.


Toyota pump valve is way to different to test in the cbr pump. After I get the kids too bed I'm going to see if I can get the PSC TC spool and output out of the Toyota.
 
The TC spool valve seems close enough that it might work but the bypass section is narrow enough that I don't think it would.

I did notice a few items of interest. The tc pump has a stiffer spring on the back side of spool valve. Almost twice as stiff and the pilot circuit port is larger.

I think i solve the mystery of the spool valve needle. I noticed this about the CBR:
CBR spool valve and fitting.jpg


With the spool valve pushed tight against the output fitting, the head of the needle is below the pilot orifice. This would create a higher velocity at this point, decreasing pressure on the spring side of the spool valve. In effect causing regulated flow to start at a lower flowrate.

I'm starting to wonder if this pump has a higher displacement, but starts regulating flow down at something like 600rpm. IF that were the case and flowrate point of regulating flow could be raise it would see an increase at idle.

Ways that the flow regulation point could be raised:
-Increasing pilot orifice dia
-Increasing Spool valve spring force
-Decreasing needle head dia

It still doesn't fix why the flow isn't getting to the ram but one hurdle at a time.
 
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