I've driven my buddies Olds Aurora and really enjoyed the 'speed variable assist steering'. Boy this would be one hell of a mod on my '79! Anyone know of an aftermarket solution ?

 

How about this

http://www.borgeson.com/xcart/catalo...-p-1-c-49.html

 

No. I already have rack and pinion power steering on the car. Around the city its great. Once highway speeds pick up though its too quick. The variable speed assist reduces the amount of power steering the faster you go. I've been thinking about adding a pneumatic valve inline with the power steering hose, so that I could just hit a switch (for highway) to reduce the pressure the rack and pinion gets. Just wondering if there is a kit out there already.

 

Interesting idea there. It would be nice if one could select power assist for parking and cruising, and switch it off and have the improved feel of true manual steering for precision driving.

 

I looked into this a bit. Gm's magnasteer power steering is controlled by the antilock brake module. This would be very hard to swap. But a quick search on Google came up with a Ford system that has a seperate control module.

http://www.aa1car.com/library/2004/bf10434.htm

It works by using a vehicle speed signal, and increases electrical current to the variable assist solenoid. The solenoid restricts flow, the more current supplied the less the assist.

It also has a steering wheel sensor that will allow the system to give full assist during rapid turns (evasive maneuvers). That would not be easy to swap over.

So if you're running a transmission with an electronic speed sensor to tap into, all you would need to do is swap the solenoid and the control module. The solenoid would also have to be adapted to fit the gm power steering pump/steering gear.

 

thanks learning_curve. I have an old 700R tranny. Gives me something to chew on. Boy you'd think with all the thousands upon thousands of hotrods out there there would be a kit out there for us guys to tweek back the power steering on the highway.

 

Great idea while it is working correctly!GM had a crude variable assist system on 97ish trucks,from what I have read the steering wheel position sensor is very unreliable and usually fails at the worst time.
It does use a solenoid valve that mounts in the back of the pump,it would be cool if that could be mounted to earlier pumps and some kind of simple control be used to cut (or boost) assist as desired.

 

I looked through my old files and I found the following on Ford EVO work. Here is an important bit of information. I am sure that a Ford EVO solenoid is the same as the GM solenoid. So a stand alone Ford controller should control a GM EVO valve. Also there is some information on a Ford system where the driver could switch to full on, full off, or speed variable assist. This might work for an on-off system that you mention.

Here are my notes and some information from Ford:
-----------------------------
Ford EVO Information

EVO stand alone controller available on 1992 thru 2002 Mercury Grand Marquis and Ford Crown Victoria on vehicles without air suspension. Their stand alone controller requires a handwheel sensor.

I'm recently retired as a suspension/steering development engineer on Ford's Panther (Lincoln Town Car, Mercury Grand Marquis, Ford Crown Victoria) platform. I have worked on both Hydroboost and EVO.The EVO is controlled by the RAS module that combines rear air suspension and steering into one control. On models that didn't have airsuspenion there is a stand alone module, but I don't recall any of them being combined with the EEC module.

We introduced a steering select switch on the 95 Town Car that allowed the driver to lock out EVO, put it on fully (max assist) or in the middle position it changed with speed like all the others. In the 2003 model year Panther EVO was replaced by the Ford VAPs system. (FORD VAPS had the valve integrated into the steering gear.) VAPs is much better in that it provides greater effort range, but of course it's more expensive.

In 2003 our Panther platform started using a panic assist feature that Bosch had which also worked very well. EVO was standard from 92 to 2002 on all Panther. It was removed from Police units for a couple of years near the end. A stand alone module would be available at a wrecking yard from any of the others unless they have RPO air suspension or on Town Car which uses the RAS module mentioned. Both are behind the glove box door - at least the later ones.A steering wheel speed sensor is required as pump "catch up" will be encountered in quick steering movements at low flow of around 1.2 GPM.
------------------------------

A good number of GM pickup trucks, SUVs, Buick Roadmaster, and possibly the Caprice used the EVO valve. Most of these vehicles use the big Saginaw P-pump (same as the 1963 through 1982) Corvette pumps. So an EVO valve that fits the above vehicles should also screw right into your Corvette pump. Just remember to continue using the flow control valve that is in your Corvette pump. Corvettes use a special valve with a low pressure relief setting. Do not use the valve inside the pump that came with the EVO valve. That valve will have a much higher pressure relief and will cause your Corvette hoses to leak and fail.

Jim

 

 

I've been looking for an excuse for a trip to the local junkyard.



Rick B.

 

This looks like a good winter project. Jim you couldn't send a larger diagram of the EVO and pump system , could you? An old guy like me can't read / see the tiny lettering.

 

This is actually looking feasible.