On reducing power steering pressure

[denpo]

Ok, I'm almost done with my Gilmer belt setup, and turns out I need a custom machined power steering pulley to get the setup complete.
I'm running a Borgeson steering box and a hydroboost.
From what I've read it's recommended to lower the power steering pump pressure do get the right steering feeling (I have a borgeson P/S pump reduction kit wainting on my shelves).
Since the pulley is custom I though it would be neat to lower the pressure by making the PS pulley bigger (don't worry, it will be smaller than a stock pulley anyway, so no clearance issues).

So, I have two questions :
-By how much the pressure have to be lowered?
-Is the rotation speed / pressure relationship is linear? (ie half speed = half pressure)

 

[Stroker-427]

I think you should change the spring in the bypass valve..... the rotation speed is much related to the flow instead of pressure.

I should keep the flow quite high in order to avoid problems of lack of steer assisting in the initial brake action.

At least this is my feedback with steeroids, hydraboost and KRC pump !

 

[mrvette]

I have a rack in my vette, running with the lower pressures of the stock '72 vette setup, and to ME the feel is fine, with HB also...both have what I consider great all around performance....YMMV....

but the serp drive pump I have is from a stock '88 vette setup, with the '72 valving screwed into the unit....which is a flare fitting.....and adapted to the rest of the later line fittings....

I would think to try it with your stock pressure set up and I suspect you be fine....I added P/S to my motor home, and the feeling is light, but so wife has to drive it, rather she is able to turn the wheel quick/sharp than all this 'road feel' we love in a vette....another animal....but IF it was just me driving it, I would love to reduce the pressure/volume?.....

:crutches:

 

[BBShark]

I think you should change the spring in the bypass valve..... the rotation speed is much related to the flow instead of pressure.

I should keep the flow quite high in order to avoid problems of lack of steer assisting in the initial brake action.

At least this is my feedback with steeroids, hydraboost and KRC pump !

I agree. Reducing the flow does not change the pressure, as Stroker said, it is controlled by the bypass valve.

 

[denpo]

I think you should change the spring in the bypass valve..... the rotation speed is much related to the flow instead of pressure.

I should keep the flow quite high in order to avoid problems of lack of steer assisting in the initial brake action.

At least this is my feedback with steeroids, hydraboost and KRC pump !

If I get you right it's better to have a the P/S pump pushing high PSI to keep sufficient pressure a idle/low RPM and let the valve chop off the excess pressure a high RPM. Makes sense. Thanks.

 

[denpo]

I think you should change the spring in the bypass valve..... the rotation speed is much related to the flow instead of pressure.

I should keep the flow quite high in order to avoid problems of lack of steer assisting in the initial brake action.

At least this is my feedback with steeroids, hydraboost and KRC pump !

I agree. Reducing the flow does not change the pressure, as Stroker said, it is controlled by the bypass valve.

I will have the new pulley machined to keep the same diameter ratio than stock.

Stock setup : crankshaft pulley : 7", PS pulley : 5.8"
New setup : crankshaft pulley : 4.5", PS pulley : 3.7"
For clearance issue I might have the pulley machined 4", now I know it won't affect the pressure.

Thanks the info, I had it quiet wrong :tomato:

 

[Stroker-427]

Happy to help yu man!