Modifying Powersteer Pump

[rivmasta]

Hey all,

Im not getting enough push from my stock pump for the ram - Its a Howe truggy rack with a 2" piston so Im not surprised the stocky is struggling!

I know theres supposed to be a way to increase pressure or flow - anyone know anything about it? Any help appreciated!

 

[cjsupra90]

pressure is controled by the spring/checkvalve assem... in the pump. Its been a long time since I messed with one so I cant recall but think that its increase in spring rate = increase pressure (could be the other way around though, forgot how they work...).
As for flow, its controlled by the displacement volume of the pump and can not be changed. You would have to adapt a different pump....

 

[rivmasta]

thought as much RE the flow, will try the pressure increase and see how we go.

can anyone verify that increased spring = increased pressure and give me a mud map on how to find the assembly in the pump?

 

[rivmasta]

Actually, somehting just occured to me - is there suppposed to be a vac line to the intake? if so why? and can I mod it to improve to full flow at all times?

 

[gloverman]

There is a restrictor in the pressure outlet of the pump - you could try drilling it out .5 mm at a time. we often do this on hilux conversions to get the feel right - cheers

 

[Zuffen]

Gary,

I would look at swapping the drive pulley for a smaller one (or machine yours down) so the pump revs harder.

The more it revs the more it will flow.

The restrictor in the outlet is a great start.

Remember as pressure rises the amount of oil it will have to pump rises as well. That's why you may need to up the pumps revs.

I'd try the drilling first and see how you go.

Funny I was only wondering the other day how the car was going.

 

[Zuffen]

Gary,

Forgot to mention.

The air lines to/from the power steering pump are to idle the engine up when you wind on lock.

Don't worry about them as long as they are blocked at the manifold otherwise you won't get it to idle due to the air leak.

You're going to have to invite the Sydney lextrmers around so we can look and marvel about your creation.

 

[rivmasta]

Ahh cheers rod. Wasnt sure about that one.

Have thought about making a new pulley to get the pump to spin up harder - gonna do that as a last resort. We still wanna keep the fluid temps down as much as poss and dont have a cooler plumbed in. If we do end out winding it up we'll add a cooler at the same time.

Ive heard that when the pumps get overworked and gets too hot a seal in there starts to leak and drips fluid onto the alt. Cooler is on the todo list, but we'll do that after we start racing! at the moment we just wanna drive the bastard!

cheers for the vac line info too.

Step one, increase spring pressure - we'll use washers to do that.
Step two, open up the outlet - slowly! baby steps!

And I'd be more than happy to have people over to marvel at our creation - when its back together again!

 

[XR8tt]

I'm NO expert in this field ..
But I'd suggest increasing flow before pressure ??
This way its much easier on pump...
Much much less chance of heating fluid also...
Check specs? what pump was used to drive steering on original ??

 

[rivmasta]

the rack is an aftermarket race only job req 1300 to 1500psi. We'll buy the howe pump if we have to but at A$600 plus the time to make up mounts etc we'de rather not!

Anyone know what psi the standard pump is good for?

 

[cjsupra90]

Ok, dubble checked myself and yes, increase spring pressure will increase system pressure. It works the same way as the oil pressure control setup does for the engine oil, once the pressure overcomes the spring tension on the valve, the valve opens and allows flow to bypass back insted of only going to rack so increase spring will allow the system to opperate at a higher pressure. Just remember though, if the pump can not match the volume that the rack requiers then this will do nothing for you. The pump has to exceed flow over what the rack wants or better said, in order to generate pressure, there has to be excessive flow.... I think Rod has a very good idea with pully size. pump speed will dictate flow and might be fine at hi RPM's, but not a low and with a smaller pully, you can increase pump speed and thus flow at lower engine speeds.

The valve and spring is located beind the high pressure outlet of the pump. The high pressure line is threaded into the valve and spring retainer which is threaded into the pump housing. Basically remove the high pressure line and then the adapter fitting that it was threaded in to and inside you will find the valve and spring

 

[rivmasta]

Perfect mate - thanks! Car is off to the powdercoater this weekend so i should get a chance to have a play with the pump on saturday.

Cheers!

 

[LXS-180]

I know this is an old thread, but after reading, i just had to share my current power steering problem...
I have a 1uz in a s13 Nissan and when i was building it, i didnt have the right hoses to connect the power steering.. so I left it till i had the time to get a custom one made up.

1st Problem: Running the pump with no fluid can ruin the pump

2nd Problem: the guy that made the power steering line that goes from the pump to the rack, is a good 8 - 10 inches longer than what it needed to be.. which means more volume of fluid required.

Now when driving the car, at low RPM it feels as though the power steering just dosnt assist at all, so when turning, the steering wheel sticks briefly, which i have to manually pull around to centre or ot straighten the car up...

My question is: could reducing the size of the pulley on the pump help solve this issue if the pump itself isnt damaged..?

 

[cjsupra90]

Now when driving the car, at low RPM it feels as though the power steering just dosnt assist at all, so when turning, the steering wheel sticks briefly, which i have to manually pull around to centre or ot straighten the car up...

are you talking about when returning to a straight heading direction from turning? If so, this has probably nothing to do with the powersteering. Alignment and more so Caster settings are what control the self centering effect. also, to much scrub radius will fight the self centering effects of the suspension set up.

My question is: could reducing the size of the pulley on the pump help solve this issue if the pump itself isnt damaged..?

reducing the pulley size would effectively speed the pump or for the same given engine speed thus creating more fluid volume and therefore more pressure. Again, if your talking about help the self centering effect, this has nothing to do with the powersteering system...

 

[361UZ]

next question, then - on LX180's behalf..

Are the pumps essentially the same between the varying models the 1UZ's came out of?

LX180, what model is your 1UZ out of?

 

[LXS-180]

When going around corners at speed (ie not from a stopped start) the steering isnt too bad, i know it is in need of a wheel alignment.
But when turning right for example, at a T-Intersection, half way around the corner, i half to manually assist the steering wheel to centre, or if i break traction in first gear, it feels as though its a non power assisted steering car....
Suspension wise i have Brand new Gas Shocks and lowered King Springs.. No coilovers.

 

[LXS-180]

.. and i believe the motor is out of a Crown, as it had a mid bowl sump... but i will have to get back to you to 100% confirm that

 

[cjsupra90]

next question, then - on LX180's behalf..

Are the pumps essentially the same between the varying models the 1UZ's came out of?

LX180, what model is your 1UZ out of?

I dont know about later units and other cars outside the US, but here in the States, the early models (SC400 and LS400) had basically the same pump. The only differance was that the SC had a remote resivor where as the LS had the resivor attached to the pump. The later (VVTi) might be different but I dont think so... Oversea's might be different too, but again, I dont think so.....

 

[361UZ]

.. and i believe the motor is out of a Crown, as it had a mid bowl sump... but i will have to get back to you to 100% confirm that

OK so far...
Mine IS a Crown (mid-sump). Why I was asking is because the Crown had a steering box and linkages, not a rack, so hence my question above about all pumps being the same.
Ie, would a pump for a steering box be the same as one for a rack?
But it does sound a s though the pump I have is the same as your's.

 

[cjsupra90]

When going around corners at speed (ie not from a stopped start) the steering isnt too bad, i know it is in need of a wheel alignment.
But when turning right for example, at a T-Intersection, half way around the corner, i half to manually assist the steering wheel to centre, or if i break traction in first gear, it feels as though its a non power assisted steering car....
Suspension wise i have Brand new Gas Shocks and lowered King Springs.. No coilovers.

If Im understanding you correctly, your saying that your having to assist the wheel back to a straight ahead position correct? If so, then again like before, has nothing to do with the PS.. This is a combination of caster and scrub radius, unless you have a bad (stuck) control valve in your steering gear (or rack assembly)... The control valve controls which way the fuild applies pressure and if the unit is getting stuck, it could be trapping pressure on the one side of the rack (gear) or another way of saying would be not relieving the pressure so its basically trying to fight itself (if you follow what Im saying)....