Power Steering Pressure?

[rivmasta]

Hey all,

Im running the stock pump, modified for a much larger, baffled resevoir.

Does anyone know what PSI and flow rates they run at? Also, is there a recommeded grade oil? or off the shelf whatever is fine for sustained revs?

My system is:

stock pump (may go for smaller pulley to slow it down a bit if its too much)
stock commodore actuator
into a massive 2" Howe Ram.

Are there any simple mods I can do to the pump to get it to work better for my application?

Cheers for any suggestions!

 

[Zuffen]

Run power steering fluid or ATF if you can't get the former.

A smaller pulley will make it pump harder so you need alarger pulley.

I think it's a "suck it an see" how it works situation.

I would definitely have a cooler on the return side.

 

[gloverman]

I deal with a few 1Uz offroad guys over here and They often remove the high pressure fitting from the pump and drill the hole to 3mm to improve performance. I would listen to Rod and run it first and then if unhappy drill the hole a bit at a time until you get it they way you want - cheers

 

[Deuce]

I am planning on using the stock power steering pump with a VK-VL Commodore power steering rack on my streetrod. I have in mind using an adjustable power steering valve made by Heidts Hot Rod Shop. www.heidts.com
This works on the same principle as a brake proportioning valve, allowing you to vary the pressure to the steering rack and therefore its feel. This might suit your application.

 

[StacytheBloke]

I would also like to know this as i am looking to couple my standard 1uz pump to either a standard range rover power steering box with a 2:1 steering quickener (howe or coleman) or an Adwest quick ratio range rover power steering box.

With both these setups some people have the problem of being able to turn the steering wheel faster than other pumps are able to keep up with. Bigger pulley time but you loose the ability to generate quite as high pressures making the steering heavier (not good)

A lot of people change completely or modify (by stretching) the relief spring giving more line pressure but not all pumps like this and some boxes like this even less.

Since the off road racing i am intending to do only has an average speed of 40mph (set in the rules to keep racing licences cheap) we have lots of very bumpy slow turns which like to make steering hard work, uprating the grunt as well as the speed of the steering is very important.

 

[rivmasta]

Got a bit more info overnight, evidently the rack (pic below) loves flow, not nec stupid amounts of pressure, but flow is the key. From what I gather above the mods re springs and drilling it out will increase pressure as well as flow. We'll try them all and go slowly.

Mod 1 - stretch the spring (I understand this is below the high pressure out line?)
Mod 2 - drill the high pressure out a poofteenth larger and try it.
Mod 3 - if we drill to large and the steering is too light we'll put in the proportioning valve.

Dumb question again - there are 2 nipples that look like vaccum hoses - Im assuming for low speed flow/high speed flow dependant on revs. Can anyone verify my assumption that low vaccum (IE idle) means high flow from the pump, therefore I can just block these off.

As our average speed at some tracks is in excess of 120km/h Im not fussed at all if the steering is heavy at idle, it'll be tuned to work at revs.

Great info and suggestions guys - thanks heaps.

 

[rivmasta]

actually, a mate just suggested rather than stretching the spring you should place washers underneath it, that way its 1) easier to tune and 2) adjustable for track to track. IE low speed twisty you could add an extra one in, for high speed you could take one out. Does this sound plausible?

 

[Zuffen]

Stacy,

My Rover runs 12.5 x 33 R15's and I use a small 340mm steering wheel.

The stock 1UZ pump bolts straight up to the RR power steering hose. The steering box hasn't leaked in 2 years of use and it hasn't been rebuilt in 100,000kms.

I can spin the wheels lock to lock with the palm of my hand.

I'm no Tarzan rather a week old bloke.

 

[StacytheBloke]

Washers are a great solution, bit less hit and miss too. Loving the howe ram too, they do make some lovely kit. No uk dealer for Howe unfortunately so we have to import and wait weeks for delivery.

Zuffen, Yeh that sounds about right buuut a 2:1 steering quickener makes the steering twice as heavy as a side effect.

100,000 km for a steering box is a dream, in our racing they are lucky to make it to 1000km (we only do 10km rally style sprints) 5 or 6 day.

As i side line for you off roaders i have just seen the new bowler nemesis based on the range rover sport, (build 10 mins up the road from me)

http://www.bowler-offroad.com/Nemesis/Nemesisoverview.htm

very sexy, especially the rear bodywork