Reducing power steer effect.

[kelvin2164]

I have a VN Commodore rally car and the power steering is just so vague, no road feel at all. So I figured I'd try reducing it. The power steering pump has a pressure relief valve which limits pressure to the rack. I squashed the spring down and so reduced the pump pressure. This seems to work, but sometimes the steering goes very stiff for a short time, like no power steer. I don't want that, a bit scary infact. Any ideas on reducing the power steer effect.

[delcowizzid]

fit a manual stearing rack is the best bet

[kelvin2164]

Power steering 2.6 turns lock to lock
Manual steering 4.5 turns. I don't think I can move my arms fast enough to keep up with 1.3 tonnes of wayward Commodore.

[delcowizzid]

the other way you could do it is change the lengths of the arms bolted onto the struts that the tierods bolt on

[immortality]

i wonder if you have a issue with fluid temp and aeration of the power steering fluid.

it may be a good idea to fit a cooler to the power steering system. just use a small trans cooler and plumb into the fluid return line that runs from the rack back to the bottom of the power steering pump reservoir.

something else to consider is something like this Clarko's Performance

[agrsv8]

just fit a restrictor in the output line of the pump, will limit the flow to the power steering rack and will be constant throughout the range

[kelvin2164]

Don't like the restrictor idea. It's going to restrict volume not pressure. So on rapid lock to lock, it will start off at full power assist and go down to no power assist as it runs out of oil volume, cause it can't flow past the restrictor fast enough.
I believe there is a flex valve in the head of the rack which deforms when the steering wheel is turned. If this was stiffer it would probably do the trick, but that's beyond my skill level.

[vr1uz-fe]

there is two main types of rack variable and no variable this is not the power side this is gearing you want the non variable

[VK_3800]

I had this problem with my series 1 VN V6 in the VK, steering so light that the weight of your hands on the wheel would make it twitch over bumps! I got a slightly later model power steering pump which appears to have a different valve setup, this made it a lot better. Its still light, but you don't get the vague wandering feel any more.

The restrictor can work, I believe some earlier Holden models (pre-Commodore) had them from factory. You would want to be careful that you don't overdo it for the reasons you've listed above though.

[vr1uz-fe]

mate i think your best bet would be to talk to national power steering and ask them if they have a rack and pump setup for your needs

[Benboy]

Unlewss you know exactly what it is that you are doing (I doubt it) and likely affect on steering, leave it alone. Steering may become inoperable particularly in event of an emergency. You may cause death of someone resulting in criminal charges etc.