That collar with the grooves and holes in it is the valve. There is flex between the two shafts connected to it, but you won't be able to feel it by twisting on the shafts with your bare hands.
That collar with the grooves and holes in it is the valve. There is flex between the two shafts connected to it, but you won't be able to feel it by twisting on the shafts with your bare hands.
Yep, that's how the power steering works. There's a torsion spring in the quill, and when there is torque across the quill it causes passages to open and fluid to go to one side of the ram or the other in a negative-feedback loop situation. You can replace the torsion spring for stiffer/weaker springs to get different steering feel.
There are stops built in to the quill so the spring can't travel very far, probably so you don't damage it if you have to drive the car with unassisted steering due to fluid loss/belt loss. Practically speaking, it is a non issue. There's more play in the U-joints in the steering shaft and there's more slop in the rubber in the tires. Or, for that matter, the slop between the bones in your hand and the steering wheel. Silly meat interfaces...
Ok, I'm gonna run it as is, I couldve swore it was a solid shaft, learn something new most days.
So, im bringing this back from the dead.
How adaptable to an existing column is this? Im thinking about it for my murderous miata challenge car. But only if it proves too difficult to drive on course with the depowered rack.
Column-assist is pretty adaptable, it's not much harder than installing a quickener box, basically the unit comes with a column section attached to it and you have to get that column section into your column, either by mixing u-joint bits or doing fabrication work.
Cool. Cut and weld, grind to fit?
May have to keep my eyes open for a vue in pullapart. Then its a matter of getting a controller and wiring it up. Right?
For all of the guys who are saying “welding/locking the spool valve is silly/unnecessary”, I beg to differ. This seems to be highly dependent on the design of the spool valve in your particular power steering rack, likely combined with many other things like weight over your front tires, scrub radius, caster, etc.
Apparently, on Miatas, this is not a huge issue. The spool valve must have very little slack, and we all know they are light with 50/50 weight distro.
However, on my Escort (2550 lbs, but 65% on the front tires) there is nearly 1/4 turn in either direction of “slop” before the spool valve hits its internal stops. This is not particularly noticeable during street driving, because the force required to turn the car is less than the force to bottom out the spool valve. BUT… slap some Hoosiers on the car and drive it on a tight autocross course and WHOA BOY, it’s like trying to drive with an elastic band connecting the steering wheel to the tires. Very frustrating!
(As a result, this winter I’m either reinstalling power steering, or pulling the rack out/apart and locking up the spool valve. I’m leaning towards power steering since 275/35R15 A7’s are in my future.)
Tl:dr – For a depowered setup or a powered steering column connected to a formerly hydraulic rack, do not be surprised if you end up needing to disassemble the rack & lock the spool valve to avoid an unusually “springy” steering feel.
Dusterbd13-michael said:Cool. Cut and weld, grind to fit?
May have to keep my eyes open for a vue in pullapart. Then its a matter of getting a controller and wiring it up. Right?
Pretty much, of course you also have to mount the body of the unit to the frame of the car somewhere, and make the mount good and stiff or flex in the mount will make the steering feel sloppy.
What does the control box do ?
I can see a use for power steering at low speeds and parking for light cars but does it get turned off at higher speeds ?
The control box basically keeps the EPS unit from freaking out by pretending to be the computer(s) it's used to talking to. Also lets you adjust the assist level. It can be varied by speed if you use a real speed input, don't know how much adjustment is available for that though.
In reply to tuna55 :
Both Ford and GM truck racks use the CAN bus to vary boost. The racks will work without the CAN signal, however they will always be in a sort of overboost mode. To get the rack to work without the CAN signal is easy peezy. Just connect the high current positive and negative wires to the battery. Next, connect the IGN wire to the ignition switch. I reckon the hard part is to get the rack to fit your application.
I was just thinking about a challenge budget friendly way to build a controller. Ebay kit us 80 bucks, but adjustable. Any idea how to clone it for 10-20 bucks?
With further research, it appears the prius epas column and ecu will work in a limp mode. Just power, ground, and ignition on. Fixed level of assist though.
If you Google failsafe electric power steering conversion you'll stumble upon a guy who has done all the research on units that work in failsafe mode.
It works well in my road car but i wished now i kept the manual rack and just assisted that rather than going with a dry power rack. I've nearly been caught correcting some oversteer and not having the steering wheel react quick enough. It's perfect for everyday driving but you can't flick the wheel like drifters do. If I could find out how to add more assistance via controller I would.
In reply to Craigorypeck :
Is that because of the torsion rod un the depowered rack, or the electric steering column? I ask, as thats exactly the kind of feedback I'm looking for .
Saturn Vue column. This one is in my friend’s FP Miata. You can run it by itself, or you can get a controller that lets you adjust the amount of assist the motor gives you. It’s friggin awesome.
Care to explain the run it by itself option? I haven't seen anything on the vue column about doing that. Just the Toyota stuff.
That was poorly worded on my part. You can make it work and it will provide the standard assist as if it was still in a Vue, or you can add the controller which allows you to change the amount of assist.
Dusterbd13-michael said:In reply to Craigorypeck :
Is that because of the torsion rod un the depowered rack, or the electric steering column? I ask, as thats exactly the kind of feedback I'm looking for .
The depowered powered rack is quicker than my manual rack by at least one turn lock to lock. This makes it tougher to turn and pushing the hydralic guts takes more effort. If I turn off the electrical assistance its near impossible to steer stationary. If it was easier to steer it may react faster... Or it still may have the same issue.. If I lift the front wheels off the ground it and flick the wheel it doesn't go very far, if that makes sense!
My Nissan unit.
I mounted it in the engine bay.
Welded the splined reveiver section to my existing column.
The unit it mounted to the bulk head and has an arm to anchor it steady to the chassis rail.
Your comment about it not reacting quick enough was what i was referring to. I didn't word it well. But that is a clean install. Hadn't thought about mounting the motor on the engine side of the firewall.
I hash about all the time and near ended up in the ditch.. I was figthing that wheel to straighten the car out.
It rarely rains here on the plains of alberta so not too worried about the unit in the engine bay
Craigorypeck said:The depowered powered rack is quicker than my manual rack by at least one turn lock to lock. This makes it tougher to turn and pushing the hydralic guts takes more effort. If I turn off the electrical assistance its near impossible to steer stationary. If it was easier to steer it may react faster... Or it still may have the same issue.. If I lift the front wheels off the ground it and flick the wheel it doesn't go very far, if that makes sense!
Did you open it up and remove the hydraulic seals, loop the lines on the hydraulic fittings, etc? If not there could not only be extra friction in the rack, but chambers acting as pneumatic dampers on your steering now. A properly depowered rack should feel the same as a manual rack of the same ratio.
Being able to flick the wheel to quickly get a ton of countersteer also requires a plenty of caster, the wheel won't do the same thing if the car is in the air.
Spoolpigeon said:
After reading through that, using one of those Japanese units looks like the best choice.
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