Power steering 3 port vs 2 port
 

So we have a power steering pump with 3 ports and a rack with 2 port. Since the rack only needs a pressure and a return, can we cap off one of the ports on the pump? which port would that be?

I believe both the rack and pump are from S4.

Thanks!

PS tried searching but came up mostly with people converting to electric or depowering :(

I havent seen too many 2 port racks...

This might be useful or not. I ran a standard "single out" pump with my miata swap (the stock one) with a 3 hole rack. At first i plugged on hole, and ran the pump into the other. This provided about NO power at all. Steering felt like it did with the car off. Then i switch the inlet and outlet so that i ran power steering into the top most inlet and this gave me awesome power steering.

Not really sure what the other inlet does... either its extremely fine (but seriously felt like no power steering at all) or it acts as a bypass for the pump to vary the pressure.

sidenote: the 3 hole racks are faster ratio!

the training manual explains it, but its something like a bypass. Foxed.ca - Mazda RX-7 Manuals

it seems we cant edit our posts on this site???

meant switched the inlets around.

reading manual now.

Thanks for the pointers guys.

Found this thread, pretty useful. But we have the opposite problem. 3 port pump with 2 port rack. So I'm curious what's that 3rd port on the pump (ie how much pressure, is it ok to just block it off)
https://www.rx7club.com/drifting-226...ering-1031074/

Manual seems to only tell you how to rebuild the rack. Could not find anything on how the 3rd port reacts to different speeds.

You could just depower your rack (the right way, shown elsewhere in this and other forums), makes things a whole lot easier and less cluttered in the engine bay...deleting my power steering and swapping to a manual rack is one of the best moves I've made w/my FC...night and day difference. Just a thought. Good luck either way!

The third port on the pump applies pressure to the spool valve on a three port rack. It's is for feel. As far as how much pressure it sees I dunno. You can probably find a way to redirect it or cap the sub-pump internally (I think the sub-pump for the third port has a separate pressure bypass). Its not a super complex system; read the training manual posted above.

does anyone know, are all 2 port FC power steering racks 17.4:1 ratio?

yes

3 port racks are superior :wiggle: