HEY BEAU!! So... does that mean you are going to catch a ride with Bart to next year's 'Zoo???? :D
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HEY BEAU!! So... does that mean you are going to catch a ride with Bart to next year's 'Zoo???? :D
Oh man I am drooling just waitng to see the goodie list! :drool2: Glad to see you checking in safe and sound....even if it is just a teaser of things to come! :D
Hello all, long time no see. So I have been out contracting in 3rd world countries for longer than I’d like, and while it has gotten better over time, I haven’t been home all that much over the years. I should be starting a contract now where I am home significantly more and the VX will hopefully finally get the loving she deserves. Here’s what’s been going on up to this point:
I ordered two Artec trusses for the 60 and the 14B axles. They are Artec TR1401 and TR6031.
http://www.artecindustries.com/asset...d60f03tone.jpg
http://www.artecindustries.com/asset...bolt-three.jpg
I still need to do some measurements to see what I am looking at for clearance with the steering. I want to do 50 degree steering using Branik Motorsports clearancing service. I still need to measure the axle tubes to see if I can get away with shortening them. Over the ensuing years, I have cut the old “inner C’s” off to make room for the Solid units. Now would be the time to shorten the axle width if it is going to happen. More on that later.
One of the things required to keep everything street legal is a parking brake. Most parking brakes are a little shoe on the inside of a brake drum. This is what the 14 bolt rear axle used to have before I dropped the dually drums off of it and converted it to single wheel and disk brakes. Now, there is effectively no parking brake. So I looked into alternatives. There are a lot of expensive options out there like this one:
http://www.northwestfab.com/assets/i...rakeresize.jpg
For the low low price of $399 you too can have a transfer case parking brake!
Or, you can just make a mount, cut a piece of ¼” steel into a circle (for the disc) and buy one of these for $100:
http://www.wilwood.com/Images/Calipe...Caliper-lg.jpg
I am ditching the stock E-brake handle because the mounting location for it is about to become a shift lever forest. I picked up a new blingy one from summit racing’s clearance rack for ~$20. I think I got a pretty good deal:
http://www.tennesseespeedsport.com/m...H/EHB-9200.jpg
Moving on to the steering, which I am about to tackle next. I am attempting full hydraulic steering and a behind the axle mounting scheme with reversed high steer arms. Hydraulic steering is powerful, but has a bit of an Achilles heel. It is usually positioned out in front of the axle right where it can get bashed by rocks. So people mount it up high to hopefully avoid that. This is where high steer arms come into play. They bolt onto the top of a steering knuckle instead of about 2/3 the way down where your tie rod usually goes. I took it a step further and turned the high steer arms backwards (so they face rear) I am planning on mounting my ram above the pinion area of the axle to provide it some additional protection. The pinion area acts as a shield/sled as far as rocks are concerned. I am kind of going for what this guy has, minus the leaf springs:
http://www.dana60.com/sceep/jeep/hydro8.jpg
I am a bit saddened because the ram I wanted to use is no longer being produced. Sean Stapley at Performance Offroad Systems is no longer in business and by all regards, his were the best. The current options available are:
>Surplus Center Ram-generic, but fairly affordable. Has welded on mount-not preferable, but it will work. Comes in at $225.
https://www.surpluscenter.com/produc...Cylinder_L.jpg
>Howe Racing-Highly regarded performance/quality, not highly regarded customer service. Looks blingy as hell, costs ~$800.
http://www.howeperformance.com/wp-co...2-1024x682.png
>PSC ram-Well regarded ram, great customer service. Uses a 2 piece piston design and has reports of it becoming unscrewed. Costs: ~$330
http://cdn3.volusion.com/xthna.vedkt...-SC2213K-2.jpg
>Trail gear ram: Usually regarded as the budget cookie cutter ram, good customer service. Only ram to publish their internals. One piece chromoly shaft. Costs: $300
https://static.summitracing.com/glob...2-1-kit_xl.jpg
The thing that always sticks in my craw after reading through the hydraulics bible is the port sizes on all these rams are AN-6 (3/8”). Most Orbitrols (steering valves) are somewhere in the neighborhood of ¾-16” ports. The KRC pump is an AN-6 on the pressure side and an AN-10 (5/8”) on the return. One of the main tenets of hydraulic system design is to keep your stuff all the same size to avoid cavitation and excess heat. So that gets me wondering if I should try and bore the ram sizes up to AN-8’s (1/2”) and size everything else accordingly. They sell ¾-16 to AN8 plugs for the orbitrol. The pump is still limited to -6 unfortunately.
So it is time to start spec’ing out the system. For a good hydraulic steering system, there are a ton of considerations. There’s a pump (the heart), an Orbitrol valve (the brain), a reservoir (the blood supply), a filter (the kidneys/liver), a cooler (sweat glands?), and all the associated lines and fittings (arteries/veins). Generally it is considered better to have hardline over flexible line whenever possible, and to keep bends and fittings to a minimum as well as size changes.
Here’s the heart of the system. It’s a KRC Pro Series aluminum pump. Supposedly they are the same size and mounting as a standard GM power steering pump and are capable of good flow and pressure numbers through swappable valves and fittings. I went with the largest of both for an output of 1600 PSI and a flow of 3.17 GPM.
https://www.southwestspeed.com/parts/KRC_63201_000a.jpg
The Orbitrol Valve is usually a tricky one. There are a plethora of configurations and options out there. Some are critical, while others are completely unnecessary. We need an Open Center, Load Reactive, and Manual Steering Check valve unit at the very least. We also need to match flow and pressure ratings to the rest of the system. The flow determines how many steering wheel turns it takes to get from lock to lock on the steering wheel. The pressure determines how much force is behind the steering (important for steering feedback and turning large, grippy tires on dry surfaces or in rocks).
Additionally, we can spec in things (usually relief valves) that protect us and the steering system from harm. Other options make our lives easier by doubling or altering steering output under certain conditions. This can give you tame, familiar, predictable steering under normal (and high speed) driving conditions, while giving you the ability to turn the wheels lock to lock in only 45 degrees of steering wheel arc(not even one turn), which can be nice in the rocks and slow stuff. I have picked out an Orbitrol valve (they are spec’ed out with a 30-something digit serial number), but I am waiting to hear back from Eaton on cost/availability. This is what an Orbitrol (sometimes incorrectly referred to as an Orbital) looks like:
https://images.4wheelparts.com/aux_i...GI&w=330&h=330
The reservoir is (in my opinion) where most people screw up a hydraulic steering system. A reservoir should be sized at double the flow of the pump. So in my case, over 6 gallons of hydraulic fluid. Think a water cooler bottle, plus a gallon. Most off-road vehicles have reservoir sizes sized in quarts, not gallons, then act surprised when their systems overheat or they are burning out pumps. I brew my own beer and use Cornelius kegs to brew, ferment, store, and dispense my beers. Originally used for soda fountains, the kegs went out of favor in the beverage industry as they switched over to disposable plastic bags inside cardboard boxes to hold the flavored soda syrups. “Corny” kegs hold five gallons, made of stainless steel, have high flow fittings, a depressurization valve, an opening you can get your entire arm into, are cheap and readily available new or used, and finally, are rated for 130 psi working pressure and 300psi ”burst” pressure. Burst pressure is usually actually 3-4 times that, so you have a very safe operating range for the side of the system (return) that is supposed to be working in the single digits of psi. Coupled with other pieces and parts of the steering system (cooler, accumulator), my system should be well into the 6 gallon range. Here’s a Cornelius keg:
http://www.homebrewfinds.com/wp-cont...n_img_3150.jpg
The filter is a bit of a nebulous point in the system. Many off-road systems use a simple screw on automotive style filter. It looks like an oil filter because essentially, that’s what it is. They are relatively cheap, reliable, and can be scaled up just by changing the size of the filter. There are also industrial type systems that use an external screw on filter body and an internal filter cartridge. They are usually sturdier and higher flow, but the filters are not as available/accessible and can be a bit confusing to deal with. I am currently looking into options for the cartridge based industrial versions, but I may end up with a simple spin on.
https://www.munciepower.com//cms/fil...er%20Group.png
The cooler can be anything from passive aluminum heat sink fins, to a more recognizable radiator and fan style unit, to a complex shell and tube fluid heat exchanger which uses water to cool the oil. I picked up a couple foot long aluminum heat sink style cooler for a return to the tank. I chose this for several reasons:
>I’m a cheap SOB and it was an impulse buy off the clearance rack at Summit
>it is aluminum and should theoretically have a lower pressure rating (engineered weak point) than the stainless steel reservoir (I would rather have the system have a critical failure outside on the frame rail heading to the tank vs. inside the vehicle)
>It is effectively a length of hardline, but cools the fluid better due to fins and aluminum’s superior heat dissipation properties.
>I will run a conventional style radiator/fan style cooler as well, but am waiting to see where I have space, and how much before I specify it.
Looks like this, but with only a single hole at each end:
https://www.etrailer.com/static/imag...D13267_500.jpg
In addition to the conventional systems found on a hydraulic steering setup I will be mounting the two Sprague accumulators. One to the high side, the other to the low side. In many systems there is little to no provision for “shock absorption” beyond a relief valve. The problem with this is found when an obstacle (rock, stump, etc.) is encountered, especially at speed. The feedback in the form of a pressure spike typically grenades the system, usually at the pump. Relief valves simply cannot open fast enough or flow enough to compensate. This is one way an accumulator can come into play. By acting as a shock absorber, the air side of the accumulator temporarily gets more compressed. As the spike passes, the air just pushes the excess fluid back into the system at a rate it can manage. On the low side the accumulator can act as a pressurized reservoir to assure fluid is always available to the system, even in the event of an off camber situation, or, in rollover conditions, long enough to turn the vehicle off to avoid system damage.
So, that about sums it up for the steering part of things…… but no, just kidding, it doesn’t. I have an ace up my sleeve. I found a PTO, or power take off system, for the NV4500 transmission. It is mounted up right now on the passenger side PTO port. The plan is to mount a PTO hydraulic pump which is capable of significantly higher output than a bastardized power steering pump (no matter how blingy looking). The idea is to be able to tailor the steering to have the KRC running at high speeds for more conventional style steering and road feel as well as lower wear and tear (and heat) on the system (1600 psi max). In the rocks, at low speeds, we kick on the PTO and the higher pressure, higher flow pump (3000 psi) starts giving us 2-2.5 turns lock to lock and powerful enough ram action (doubled) to knock over boulders while steering with a single finger. A simple check valve set up to put the KRC pump into bypass mode allows the PTO pump to take over. Easy peasy.
So that’s it then, at least for now, for the steering. For real this time.
In my years of absence, I have also grabbed the tube adapters for the suspension links found in the first post on this thread. Next is to get link lengths and weld everything up, then send them all out for heat treating.
Powertrain wise, I just picked up the guts for the doubler. In the past, I was debating even adding a doubler because Justin (ZEUS) had me scared that the powertrain would be too long and I’d never be able to fit driveshafts. Well, let me tell you. I did the research and math and made these really ****ty refrigerator drawings to prove to him (and you) that I can fit a V8 engine, heavy duty 1 ton truck transmission, doubler, AND transfer case where the original VX stuff lived, plus have an inch and a half to spare! The doubler is going to be a Northwest Fab Eco box with guts from an NP 241 transfer case. It will bring the VX’s low range gearing down to around 100:1. Pretty darn slow. Here's the refrigerator drawing for reference:
http://www.vehicross.info/gallery/da...comparison.jpg
Ascinder (Beau right? We met in Moab one year), it's good to see you back on the forum. I would see your name as I would scan through old threads every-now-and-then and always wondered how you were doing and how your VX build was going, if it was going at all. From the post above it looks like you are back with a vengeance and I can't wait to see how it turns out.
Keep this thread going and keep uploading pictures of the beast.
Mark H.
Thanks Mark, I will keep updating this thread as much as possible, but I still won't be home for several months, so right now it's still just the planning and acquiring stages. I am currently working on getting the VX's frame created as a 3D model so I can start playing with positioning the powertrain, suspension links and axles. The more I can get done out here, the less hiccups I think I will run into back home. I am taking inspiration from these two designs, both of which are pushing the engine back into the cab area. I am hoping to move it back just far enough to clear things without ending up like the Comanche(red) truck with his legs pushed into the corner-especially because I have an extra pedal to deal with!
Here's the Toyota. Notice how the lines of an "Amigo bobbed" VX are similar to his rollcage/body....hmmm. It uses a smaller engine and has more clearance than the other truck. I am hoping for something closer to this as far as cab intrusion goes:
http://www.vehicross.info/gallery/da...ps8e8ad479.jpg
http://www.vehicross.info/gallery/da...toy_engine.jpg
http://www.vehicross.info/gallery/da...y_engine_2.jpg
http://www.vehicross.info/gallery/da...y_firewall.jpg
Here's the Comanche, a bit more recent build with a similar engine to what I am using. Notice how much less room the driver has for his legs:
http://www.vehicross.info/gallery/da...m/comanche.jpg
http://www.vehicross.info/gallery/da...ushed_back.jpg
http://www.vehicross.info/gallery/da..._tight_fit.JPG
http://www.vehicross.info/gallery/da...he_cockpit.jpg
Both of the build threads can be found over on pirate4x4. There are a lot more epics and a lot of good tech for anyone interested. Here are the links to each thread:
Silver Toyota
Red Comanche
Found some pics (old) but show some small amount of progress:
Here it is coming off the trailer after getting moved from the old apartment to the new house:
http://www.vehicross.info/gallery/da...m/edited_2.jpg
Hover mode from inside the garage:
http://www.vehicross.info/gallery/da...m/edited_3.jpg
Getting some of the mounting brackets removed from the frame rails. These were a godawful nightmare. If you ever had a doubt about the VX, I can tell you firsthand it is better built than most tanks. Some of these brackets were attached and welded around the frame on all four sides. I have never seen or heard of anything like that. This was an early pic. The frame rails are completely cleaned up now.
http://www.vehicross.info/gallery/da...m/Edited_1.jpg
Here's a pic of the VX where I mounted the wheels on the D60 and rolled it under. I like the stance and ride height. Stock D60's are capable of around 35 degrees of steering. With the Branik clearanced shafts, they will be able to do 50 degrees. Not sure if I have enough room for that, but we are sure going to try. The D60 has since had the inner C's cut off to make room for the upgraded units.
http://www.vehicross.info/gallery/da...maller_pic.jpg
Here's a simple mockup using to scale axle width, proper rim backspacing, tire size and steering angles for 50 degree steering. I was seeing what I could get away with in terms of suspension linkages.
http://www.vehicross.info/gallery/da...er_capture.JPG
Glad to see you gett'n "back in the saddle" Bro. I have one of thos finn'd aluminium trans cooler in the inventory, just waiting for me to get the Zombie Hunter running again...It's been so long since I ordered it, I just realized that I have NO idea where it is. I'll prolly have to move to get my inventory in order.
I know how you feel. I try and keep all my VX stuff in one corner of the garage, but I think it gets up at night and runs amok. Seems like nothing is ever where I left it. It's hard to get back into the swing of things being stuck over here and not being able to actually "do" anything. I am hoping if I get enough stuff together while I'm over here, the process will hopefully go smoother once I am back. I should have a solid two month block, so once February rolls around, it's time to hit this thing hard. If I can just get over the suspension hurdles, I think it will go pretty easily from there. The suspension is the only thing I haven't been able to visualize (and therefore plan around) because of all of the articulation and travel, and not having a VX in front of me to measure for link placement. I think I may be able to work around that if I can get this 3D model built. I have also been pretty squeamish about cutting into the VX, especially because it is still in such good shape. If I wipe the dust off, the paint still shines like brand new and there isn't a spot of rust to be found on the whole thing. Having seen these build threads and realizing I am working on an (almost) 20 year old vehicle wakes me up to the fact that it is already too far gone to worry about little things like that, so the firewall has a date with the sawzall. Talking to Justin(ZEUS), who is the chicken little/boogeyman of my build, (just kidding, he keeps me honest) he thinks I am going to have transmission tunnel issues. It's a possibility so I am preparing to perform surgery there too.
Progress so far on the 3D model of the VX frame. Struggling because this is my first time doing this, but so far so good.
http://www.vehicross.info/gallery/da...dium/frame.JPG
Looking good
Hey now! What I said was... Move the front axle forward & tilt the drivetrain downward at the t-case. Especially if you are still determined to move the drivetrain backward with a doubler! Then maybe you would not have to cut as much of the firewall & tunnel & your u-joint angle would allow you to pivot the 14B pinion up at the same angle. ...ok, I did not Say ALL that, but it was inferred! Haha I for one appreciate the detailed explanation of what you are buying and why. Did you basically research each part of the steering system and write out your own explanation of how it works in a build thread form in order to keep track of it all? Or is this part of helicopter service work? Something tells me you have been writing this section of your build for quite some time! Pretty funny that I was also the guy that said, "So moving the family to Montana is the most important priority, right?" Haha NOPE! SHOP TIME! "It's winter", he says. :D
BTW... I never told you this but the last time I was at your apartment I noticed all those books in your book case... Mathematics, Metallurgy, Mechanics, etc... yet the one book I picked up was about Physics... imagine my surprise; hidden within it was a Hustler magazine! Haha BUSTED!
What 3D program are you using?
Yeah, pretty much that. I need stuff like this for me as much as anyone else. Trying to keep track of all the moving parts and specs over the years takes a toll. Especially when you consider how many other projects I have. It also gives me some insight into how and why I made my decisions when I look back at it over time. If new tech materializes or something is found to work differently I can instantly compare without having to try and dig up old specs and research on the net.Quote:
Did you basically research each part of the steering system and write out your own explanation of how it works in a build thread form in order to keep track of it all?
I think I am going with a double cardan (CV) driveshaft front and rear. It requires you to point the axles and pinions directly at the transfer case yokes while the transfer case yokes stay at zero degrees.Quote:
Hey now! What I said was... Move the front axle forward & tilt the drivetrain downward at the t-case. Especially if you are still determined to move the drivetrain backward with a doubler! Then maybe you would not have to cut as much of the firewall & tunnel & your u-joint angle would allow you to pivot the 14B pinion up at the same angle. ...ok, I did not Say ALL that, but it was inferred!
Here's a "regular" setup:
http://www.therangerstation.com/tech...l-opposite.PNG
Here's a double cardan "CV" setup:
http://www.4xshaft.com/images/cv_angle.gif
CV driveshafts also allow a lot more articulation than conventional setups. The pinion angle on a CV driveshaft is a good thing as well as it pushes the vulnerable pinion up away from the rocks.
Up front it is a bad thing for me because between the caster angles the kingpins are supposed to be set at(usually ~6-8 degrees but can be 15-20 degrees on full hydro setups) and the pinion angle being pushed up towards the transfer case yoke, the behind the axle hydro steering setup I am planning on running might be out of space and fighting angles that may not work out. That's next up in the 3D modeling box.
For driveshafts, the two front runners I am considering are Tom Woods and High angle Driveline. they both make "over the top" shafts that excel at both strength and articulation.
Nope, all in my head, just hadn't committed it to a post. It took me a couple hours at work to pull all the associated resources. I need to get a "manual" created for this build, again so I can keep track of all the various part numbers, fitting sizes, dimensions, torques, etc. Some of these things can be difficult to track down later, and if something breaks or needs replacement, you at least have a starting point.Quote:
Something tells me you have been writing this section of your build for quite some time!
Montana is still on the table, and it would be easier to work on the VX with no interference and more space....Quote:
Pretty funny that I was also the guy that said, "So moving the family to Montana is the most important priority, right?" Haha NOPE! SHOP TIME! "It's winter", he says.
Quote:
BTW... I never told you this but the last time I was at your apartment I noticed all those books in your book case... Mathematics, Metallurgy, Mechanics, etc... yet the one book I picked up was about Physics... imagine my surprise; hidden within it was a Hustler magazine! Haha BUSTED!
That was being used as a bookmark I swear!
An old copy of Sketchup 2015, nothing special. Here's where I left off last night. The crossmembers are very rough because there is no good data on them. If I remember and if I still care, I will try and clean them up a bit once I'm home at some point and can get measurements.Quote:
What 3D program are you using?
http://www.vehicross.info/gallery/da...um/VXframe.JPG
Small update:
-I picked up the brake caliper mount brackets for the 14 bolt(rear) axle
-I picked up an NP241 HD transfer case to use as a donor for the guts of the doubler.
-I finally pulled the trigger on the NWF Ecobox doubler kit
-I grabbed 100% of the suspension link brackets. Purchased across 3 different vendors with plenty of creative modifications still to be performed.
I made some good progress getting some of the 3D models for the engine and both axles, but unfortunately, they are just too taxing for my little laptop to run. Parts for a new computer build are on the way. Hopefully i will make some progress there in the next week or two.
In the meantime, I would like to solidify the full hydro steering and keep my eye open for deals on ORI struts and lockers.
Here's the progress on the virtual build. It's sitting at expected ride height on 37's with a ~19" belly. The rims are correct, but the tires are Trepadors instead of Creep Crawlers. The engine is still sitting up very high because it takes my poor laptop a minute or two to recover from literally every move I make. New computer case showed up today and the rest should be here in a couple days, then we can really start hitting it hard.
http://www.vehicross.info/gallery/da...m/VX_layup.JPG
Some good news and some bad news.
I got all the computer parts in and assembled everything and it worked like a champ! Then I went and tried to update the BIOS and it didn't take and it was black screen of death from there on out. Motherboard is currently in transit for repairs, so likely two weeks out and two weeks back best case scenario.
Other than that, I finally decided on a ram and went with the Trail Gear Rock Assault HD ram. After seriously trying to get the surplus center ram to work out, I decided it wasn't worth the headache and went with the TG ram. I ordered the heim joints and tube adapters for it as well. I went with QA1 rod ends, PN HMR12HT and HML12HT. They are 3/4" hole x 3/4-16 threads and static rated at 52,900 lbs.
https://static.summitracing.com/glob...l-hmr10_ml.jpg
Here's the tube adapters:
https://secure.chassisshop.com/asset...-951-H-2_1.jpg
On the rest of the steering, I went round and round(and round) with the pump and Orbitrol selection. I am thinking about ditching the KRC pump and going with an actual hydraulic pump. These pumps are used in industrial settings and can push out significantly more pressure and volume than an automotive power steering pump. They also run cooler and last longer. There are however several issues with fitment. They are a bit larger and they aren't designed for over hung loads. In other words, they can't take forces from the side (like a belt driving a pulley for instance). So we need an intermediate bearing and it has to be supported. I think this can be easily done with a simple pressed on bearing into a thick aluminum plate. The pump would bolt into the plate and the protruding shaft, now supported, would be easy to throw a pulley on. The next problem is mounting them. They are closer to the size of an alternator or A/C compressor than they are to a power steering pump. I can relocate my current A/C pump up high and to the passengers side with a relocation bracket and run the industrial pump in it's place. Why not just run the industrial pump up there you ask? Couple reasons.
-Putting the hyd. pump down low allows gravity to help keep it fed.
-It puts the pump(remember, the high pressure part) further away from the cab
-The hyd. pump has no electronics(unlike the A/C pump) and so if it gets submerged, no one cares
-The hyd. pump is noisy, so now we have it down low and away from the cab
-And most importantly, it allows us to use the A/C portion of the crank pulley. The crank pulley has two drive sections. One for the A/C, and one for literally everything else. The hyd. pump draws a lot of horsepower, especially at high rpms. Having it hooked up with everything else is a recipe for trouble. This layout isolates it and gives it it's own dedicated belt.
The Orbitrol is a tricky one too. Probably the trickiest part of the whole system. There are a blinding array of options out there and to make matters worse, choosing one option changes or negates others. The orbital is the "steering box" of the system and so out of everything, we want it to work, and work well. One of the main reasons I was pushed away from sticking with the KRC pump was that even maxed out, it only put out 1650 PSI and barely 3 gallons per minute of flow. To simplify things, the psi is how hard you can make the ram(and by extension, the wheels) push. You can literally knock boulders over with one finger with full hydraulic steering. The gallons per minute(gpm) rating is how much flow you can push through your ram. This is important for steering response. When we try and turn the wheel fast (like in a dangerous situation) we want the pump to be able to keep up. As the ram sizes go up (mine is one of the larger ones) this becomes more important. The gear driven pumps put out serious psi and flow. They start around 3000 psi and can flow up to 10 times the flow of the KRC pump. We don't need anywhere near that much flow, but what we do need is enough flow to be able to run a "proper" Orbitrol". Remember earlier how I said some options wouldn't allow others? Well it turns out the low flow and psi of the KRC pump was significantly limiting my options for the Orbitrol. One of the cooler options available is dual rate steering. You basically flip a switch and your steering goes from 5 or 6 turns lock to lock(like stock steering, and less twitchy at speed) to 2 turns lock to lock, which is great for slow speed response and doing technical stuff in the rocks. It turns out most the the safety features are only available on the higher flowing, higher pressure models as well.
A few words of caution with sizing up your power steering, from a Fluid Power Engineer with 45 years experience in circuit design, including power steering circuits.
1. Will you be driving this vehicle on the roads?? In Australia, and most of the rest of the civilised world, Orbitrol units are not legal for on road use. Stupid but true. The Orbitrol units do not have the safety features supposedly found in the sector and ball-nut type power steering boxes.
2. Try and find a larger flow dedicated power steering pump if your first choice is not large enough. 5 and 7 GPM power steering pumps are readily available, and still have all the inbuilt features that a commercial gear pump won't have.
3. If you have to go to a commercial pump, try and find a high speed vane pump, rather than a gear pump. Do not under any circumstances use a gear pump with an aluminium housing. They cannot support the sustained heat and high pressure, nor the high revs.
4. You are correct that a commercial pump is not normally built to take side loads like a belt drive. Your idea of an aluminium plate with a bearing in it, is very limited. Most pump shafts are too short to protrude through the aluminium plate and still engage the belt pulley. To use your idea you will also need a stub shaft made to extend the pump shaft - female to mate with the pump, male to mate with the pulley. Some commercial pumps can be ordered with an "overhung load adapter" built into the pump housing. This does allow them to take the belt drive side force.
5. A dedicated power steering pump has 2 vital valves built into the pump. A pressure relief valve, and a pressure compensated flow control valve. If you use a commercial type pump you will have to purchase, mount, and plumb up these 2 extra valves.
6. Don't forget that the larger the commercial pump flow, the larger the reservoir required. Rule of thumb is 3 x GPM for the reservoir size. This can be reduced down to 1 x GPM if you install an additional cooler. Dedicated power steering pumps use some internal trickery to get away with smaller reservoir sizes. They also use longer routing of the return lines to allow heat to dissipate prior to returning to filter and reservoir.
7. Whatever you do, work out your actual flow calculations very carefully. Engine RPM range, dia of crankshaft pulley and dia of pump pulley and the displacement of the pump in cubic inches/rev (or cc/rev) should give you the right answers. You need enough flow at idle to slowly turn your steering, and not tooo much at high engine revs.
That is probably enough for now.
If you need any help sorting through the options of the Orbitrol units give me a yell. Unless you have been especially trained in military driving techniques, avoid any orbitrol unit that will give you live feedback. Otherwise you will break your thumbs as the road wheel hits a rock and the steering wheel spins uncontrollably out of your hands.
I have been retired for a few years now, but still do some consulting work when I am dragged back for particular problems.
PK
This has been gone over earlier in the thread and on other forums ad nauseum. The DOT does not specifically prohibit hydraulic steering, but does stipulate that steering must be connected through a mechanical linkage. We have garbage trucks in the states that steer purely through hydraulic steering so it is being done somehow. Most police here don't know and don't care about any obscure legalities regarding this.Quote:
A few words of caution with sizing up your power steering, from a Fluid Power Engineer with 45 years experience in circuit design, including power steering circuits.
1. Will you be driving this vehicle on the roads?? In Australia, and most of the rest of the civilised world, Orbitrol units are not legal for on road use. Stupid but true. The Orbitrol units do not have the safety features supposedly found in the sector and ball-nut type power steering boxes.
Most higher flow pumps that I have come across are just hot rodded (bored out) conventional power steering pumps. They burn out under full hydro use very often and are expensive to replace. What inbuilt features are you referring to? Several of the gear pumps I have looked at have built in flow and pressure regulators. What would a conventional pump have/need besides those?Quote:
2. Try and find a larger flow dedicated power steering pump if your first choice is not large enough. 5 and 7 GPM power steering pumps are readily available, and still have all the inbuilt features that a commercial gear pump won't have.
The things I have read point in a completely opposite direction. The aluminum dissipates heat better than steel. My "high performance" KRC pump is aluminum with the steel pump being half the price. The manufacturer told me they went to aluminum because the steel wouldn't hold up at high rpm/heat. The gear pumps I have looked at are all rated well over 3000 psi and 4000 rpm constant speed. Manufacturers have stated in letters that they are able to sustain higher rpms for short periods with no problems. Several people have been running these pumps in this fashion for years with no ill effects. The gear pumps(and a fair amount of vane pumps can be had for ~$100. Versus replacing a ~$3-400 suped up power steering pump at about the same rate, I'll take my chances with the gear driven models(although the vane pumps are fine too I understand they don't do as well at high pressure or life expectancy)Quote:
3. If you have to go to a commercial pump, try and find a high speed vane pump, rather than a gear pump. Do not under any circumstances use a gear pump with an aluminium housing. They cannot support the sustained heat and high pressure, nor the high revs.
I have looked into this as well. A half inch thick aluminum plate simultaneously mounts the pump and provides a pocket for the bearing. The bearing is a ~$30 NTN deep groove single roller bearing rated at thousands of pounds of load and tens of thousands of rpms. It is under 3/8" thick. The pump shafts I am looking at would protrude through the plate and bearing with 3/4 of an inch to spare. Even more if you consider that the bearing only needs to be retained with a small lip around the rim so the pulley would be able to mount right up to it "into" the aluminum plate. This eliminates the need for a stub shaft and all its additional complications. The pumps I have seen with overhung load adapters have all been clutched units which cost 7-8 times as much as the unit I am considering.Quote:
4. You are correct that a commercial pump is not normally built to take side loads like a belt drive. Your idea of an aluminium plate with a bearing in it, is very limited. Most pump shafts are too short to protrude through the aluminium plate and still engage the belt pulley. To use your idea you will also need a stub shaft made to extend the pump shaft - female to mate with the pump, male to mate with the pulley. Some commercial pumps can be ordered with an "overhung load adapter" built into the pump housing. This does allow them to take the belt drive side force.
See comment above. These two are included in the pumps being considered. They are also duplicated in the Orbitrol valve as well. Being open center with a power beyond port, the Orbitrol only uses what it needs to steer(both pressure wise and flow). Everything else is bypassed straight back to the reservoir(via either the open center or power beyond port).Quote:
5. A dedicated power steering pump has 2 vital valves built into the pump. A pressure relief valve, and a pressure compensated flow control valve. If you use a commercial type pump you will have to purchase, mount, and plumb up these 2 extra valves.
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6. Don't forget that the larger the commercial pump flow, the larger the reservoir required. Rule of thumb is 3 x GPM for the reservoir size. This can be reduced down to 1 x GPM if you install an additional cooler. Dedicated power steering pumps use some internal trickery to get away with smaller reservoir sizes. They also use longer routing of the return lines to allow heat to dissipate prior to returning to filter and reservoir.
Most of these setups(off road hydro steering) run reservoirs sized at about 1 quart. Needless to say, they overheat and it causes issues. One of my first inclinations was that the cooling was way undersized. I am confident the 5 gallons of fluid will be more than enough for my needs. I am infrequently moving a (very) small ram compared to something like an excavator which needs to do it all day long with many large hydraulics loads. The way power steering pumps deal with excess is by internally recirculating fluid. It does cause heat when the systems are under high pressure. The Orbitrol constantly circulates fluid through the entire system, not just internally. Being that I am planning on a 5 gallon reservoir, there are very few places to install it. It is likely going near the back of the vehicle. The lines will be plenty long enough to cool the fluid. A couple heater cores will likely be employed to help cool as they are rated for much higher pressure than conventional radiators. System sizing also plays a huge role in heat generation. Many systems are sized too small and the restrictions cause excess heat. I am going bigger than required on everything, so comparatively, my system will be lower pressure and lower flow than I need.
Already done, but the problem isn't in the numbers I get, it is matching it up to the configurations that work with the Orbitrols. My crank pulley is a 25% underdrive unit. With a 6.5" pump pulley, it gives me a ratio of .86 for rpms that the pump sees. My engine is putting out 550 horsepower. At 2,800rpm I am putting out what the stock VX puts out redlined. Pushing my numbers up to 5,000 rpm, I am only turning the pump at 4300rpm. Most regular vehicles seldom see 5,000 rpm, let alone most V-8's. For the very small amount of times the pump will see high rpms and the even smaller window of time it will be exposed to them, I think I'll be OK. Based on my gear calculations, at 3,000 rpm, I am hitting 110 MPH in 5th gear. The problem with these systems is we often need the most flow and pressure when we are going slowly and th least when we are driving fast. I have a PTO capable of driving a separate pump and I was considering that route, but it greatly complicates the steering circuit and seems like a compromise. I personally do not want much flow. In steering, flow equals steering responsiveness/speed. I would prefer a normal amount of turns lock to lock under normal conditions and a lower amount, but still precise while going slow in the rocks. It seems like it could be accomplished through either some Orbitrol trickery or by just throwing some check valves into the circuit to force the KRC pump to go into bypass mode while the high PSI, high flow PTO pump takes over.Quote:
7. Whatever you do, work out your actual flow calculations very carefully. Engine RPM range, dia of crankshaft pulley and dia of pump pulley and the displacement of the pump in cubic inches/rev (or cc/rev) should give you the right answers. You need enough flow at idle to slowly turn your steering, and not tooo much at high engine revs.
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That is probably enough for now.
If you need any help sorting through the options of the Orbitrol units give me a yell. Unless you have been especially trained in military driving techniques, avoid any orbitrol unit that will give you live feedback. Otherwise you will break your thumbs as the road wheel hits a rock and the steering wheel spins uncontrollably out of your hands.
I have actually been trained in special military driving techniques, and I can tell you a rig with running large tires and tight steering offroad will break your fingers off every bit as quick as a hydro unit.
I have been retired for a few years now, but still do some consulting work when I am dragged back for particular problems.
For reference, here is where I am getting a good portion of my information:
LINK