stolen from 1jzracing on toymods
this is how to modify the hydraulic pump which runs the radiator fan as comonly found on the front of most 1jz water pumps to run your power steering, i have done this over 3 years ago and is still working perfectly, you must do it where i
the pumps are the same type and generic pressure but the fan pump is set to have more flow rate. Both pumps have a built in controll valve that keeps the flow and pressure constant no matter what the engine revs are, so by reducing the outlet hole size from the shuttle valve the flow is reduced without loading up the pump or overheating the oil
check the pics the numbers coraspond to the instructions below
1. take off the banjo bolt and outlet hose
http://www.toymods.org.au/forums/attachment.php?attachmentid=3695&d=1169030579
2. take off the big bolt at the bottom remove the shuttle and spring
http://www.toymods.org.au/forums/attachment.php?attachmentid=3695&d=1169030579
3. this is the hole at the bottom of the outlet thread which needs to be reduced, drill it out and tap it m8
http://www.toymods.org.au/forums/attachment.php?attachmentid=3697&d=1169030592
4. screw a very short countersunk m8 cap screw in the new thread with a 3mm hole drilled down the center, you may need to grind down the head a little, like the picture, to fit it down the hole, make sure it doesnt poke through the inside too much and you may need to fit the shuttle and spring before screwing it all the way in, do it up TIGHT!
4. screw a very short countersunk m8 cap screw in the new thread with a 3mm hole drilled down the center, you may need to grind down the head a little, like the picture, to fit it down the hole, make sure it doesnt poke through the inside too much and you may need to fit the shuttle and spring before screwing it all the way in, do it up TIGHT!
http://www.toymods.org.au/forums/attachment.php?attachmentid=3698&d=1169030597
put it all back together
note: you CAN NOT restrict the flow at any other place such as the end of the banjo bolt this WILL NOT WORK!!! even though it looks to do the same thing. There is a tiny oil gallery about 0.5mm diameter off to the side at the bottom of the outlet hole this controlls the shuttle valve and the restriction must be BEFORE this gallery
If your game to experiment you may find easier ways of reducing the hole such as driving in a little short tension pin or something
this was also in the thread but may not be as relaible.
I wired a car that was setup like this on the weekend but instead of modifing the pump I used a jaycar motor speed control kit on the solenoid. Changed a capacitor in it to drop the frequency to about 100hz and all was good.
Just wound it up until the steering felt good. For anyone that had too much spare time it could be made speed sensive as well.
cool!
now thats a cunning idea
You might find that the flow is still a little much.
Flow and pressure are two verry different things, the power steering only calls apon pressure as its needed - ie the more effort on the steering shaft the more oil is directed to the piston building relitive pressure instead of recirculating back to the reservoir.
if the flow is too high there can be too much over all pressure in the system as the oil cant pass through the valving servo fast enough, my car popped the seal out of the steering rack at the steering shaft when i hooked it up without the restrictor
the solenoid controller on the hydraulic fan pump may only controll the pressure not the flow - I could be very wrong not sure how it works, if it does controll flow then its perfect!
let us all know how reliably this works, could be a much easier solution
yeah I wouldn't have a clue, it worked perfectly for the 10 min test drive.
As I wound up the speed controller I could here the fluid noise begin like normal power steering does as the air etc gets out of it.
I'm sure i'll hear about it if anything explodes in the future
