Hi, researching just now I come across conflicting information, so I thought I'd ask: will the existing pump from my recirc ball steering work with a later model power rack? I have a line on a cheap rack with new tie-rods and the other key pieces, but no pump or hoses. I've seen people say that the recirc pump works fine with the later rack, but also that the 79 pump is a different part number than the 80-83 pump. Am I getting myself into a world of hurt if I take the rack/crossmember/brackets/column coupling/pulley but don't have the pump to go with it, or should this be easy enough to work around? Shouldn't it work fine with the old pump, or is there something I don't know?
I would be concerned about the rpm sensitive boost properties of the recirculating ball system. This allowed for higher boost at parking rpms and very low boost at highway speeds. I'm assuming it's the pump that does this. This was way ahead of the times when the 280zx came out in 78, you do now about this feature of the rec. ball steering right? Maybe the rack will not like the boost changes, as I don't think the rack system uses this rpm sensitive system.
At least having cars with both systems, I don't think the rack system does. Why change, my 79 drives and feels fine. I like the low boost at speed. The 82(gone) and 83 I have do seem a little different, but I can't say better. They still have the same steering wheel lock to lock numbers and ratio's.
The 79 does have higher boost at slow speeds compared to my rack systems, I think that is why it feels different. Again, I really do like the lower boost at highway speeds of the 79.
Well, the switch to a different pump that happened in 1980 was for the same recirculating ball system, and stayed on through the power rack, though perhaps spinning at a different rate with different pulleys, but I don't know how much difference that would make. I've driven both types and though I agree the recirculating ball is much better than the one in a Buick, like many people I prefer the power rack. Moreover, the existing steering on the car needs new tie rod ends, while the rack I've sourced has them already, so the parts cost of the switch isn't all that much more-- as long as I don't need to run around looking for a different pump or pulley to make it work.
And I guess if you are going to turbo the car ever you need to go to rack because the steering gear box would be to close to the turbo.
Maybe the 79 is the only year to use the pump that shuts down boost at higher rpm's. Maybe the average American driver did not like the heavy steering. A lot of sports car trade off's with the 280ZX design(soft ride ect.) to attract non-sporting drivers to buy this car when new. They got it right with the 82 and up turbo's though.
A lot of people that had no idea how to drive a sports car bought these and I've seen a good many off the road and upside down cause the owner had no clue how to drive them back then.
No plans to turbo the car. After I've got the steering, brakes, and suspension sorted this spring, I am considering as a long term strategy going for megasquirt and some limited head, intake, and exhaust improvements. I think an NA car with about 50 extra lb/ft at the wheels above stock would suit me better than a turbo, as I'll be using the ZX for GT duty and not primarily as a sports car.
Continuing to research this, I still haven't found anything to substantiate a difference in operation between the 79 and 80-83 pumps, but there is definitely a difference in their mounting points so it seems that I would be almost obliged to try to run with the older pump unless I changed the mounting bracket or made an adapter that didn't push the pump out of line with the belt. The hoses remain the same for the whole run of the recirc ball setup, 79-81, i.e. for both pumps, so switching to the later hoses should present no problem.