Is there an easy way to convert from RPM-sensing to road speed-sensing PS?

Could you do it by changing the computers, or would you need to get ALL of the parts, rack, pump, and everything else?

I suppose one might as well, since it has a tighter steering radius...

 

Why would you want to convert to speed-sensing? I though the GTUs's, Infini IV's and the FD's had the better RPM-sensing steering setup...?

 

I`ll just throw this in for all to think about. On my `86 GXL I`m running the Megasquirt 1 Version 3.0 PCB with MSnS-Extra. The trailing coils do not fire below 800 RPM because that is how the current software is written. Anyway, when I am comming to a stop if the RPMs go below 800RPMs the tach drops out (0 RPM). When this happens my power steering computer beeps twice followed by a pause then twice etc. until the RPMs come back up. According to the FSM this two beep code is because the PS computer is not getting any speed input.

Because of this I would think that my car uses RPM based sensing. What do you think???

 

RPM-sensing is crap... it would be great if it did it based on what gear you're in, but instead it just changes it based on how high you're revving the engine. WTF is up with that?

They only made it like that because it was cheaper...

Also, the vehicle-sensing rack is 2.7 turns lock-to-lock, and the engine-sensing is 3.0, and tighter is better, imo...

 

Wrong! Here's the list of which cars came with which steering racks. There's no direct relationship between year and steering rack, it also depends on the model. All of the factory manual racks were 20:1.

The cars that got the 17.4:1 ratio racks are as follows:
The 89-90 GTUs, 90-91 Infini, 91 Coupe, 90 GXL, 90 GTU, and the 90-91 Vert.

The cars that got the 15.2:1 ratio racks are as follows:
The 86-89 GXL, 86-87 Sport, 88-89 GTU, 86-87.5 Base, 87.5-88 SE, 86-87.5 Luxury, 87-91 US spec Turbo, and the 88-89 Vert that were equipped with power steering

I do beleive that all S5's were RPM based and all S4's were speed sensing.

IMHO the speed sensing is a better idea.

 

The S5 turbo was speed-sensing... and so was the 89 GXL and convertible, according to the brochures, although those aren't always right. According to them, ALL of the racks are 2.7 turns lock-to-lock, but the FSM says the RPM-sensing is 2.7 while the speed-sensing is 3.00... wierd.

What I guess I want to know now is what seperates the two besides the fact that the speed-sensing setup has three lines and a different computer?

Don't the pumps use the same connector too?