I recently installed Corsa C manual rack with Flaming River steering uni-joints into my SA22 Gen 1 RX7.

It is a 3 to 1 ratio which is faster than the standard 3.5 to 1, and it is quite a bit lighter as well. Next to zero play, next to zero flex, I highly recommend it.

Full details here:
Project Part 7 - Engine Build, Megasquirt, SDR manifold, rack and pinion steering



Arran

 

Nice work, terrific information Arran, thanks!

 

Id love to see some more pics!

 

Many cars have electric steering racks now, does the motor simply detach from the rack, effectively making it a manual rack?

 

It's amazing what a new or rebuilt steering box does. Not as good as a modern rack&pinion system, but totally acceptable.

 

How much play does yours have, because I have about 14 mm, still have some things to do to the car, but thinking that's as good as it gets probably. I actually like the stock steering, just don't like the nervousness that comes from on-center play.

 

The Corsa C (rebadged as a Holden Barina in Australia) had what is called an EPAS system: an electric power steering motor on the actual steering column. So yes, the rack is in effect a manual rack. The difference is in the steering ratios, with manual racks having a ratio requiring less steering effort.

No matter what you do, you cannot eliminate the wonder steer on 1st gen RX-7s - it is an inherent flaw in the recirculating ball design. I've found series 3 units (84-85) are worse than series 1 and 2 possibly because Mazda wanted to make the steering lighter, which in turn made the freeplay issue much worse. Reco'ing or simply tightening the steering box helps, as does new steering system componentry, however the basic limitations will always remain. It's like putting lipstick on a pig.

Steering effort on a stock car isn't so bad, but add some wider stickier tyres and some decent alignment settings (a bit of extra caster) and it's ridiculously bad for such a light car.

Rack and pinion conversion is the way to go and the FC subframe conversion is probably the best way to do it IMO: modifications are required but they aren't extensive plus you get a mid-mounted engine with OEM engine mounts, bigger stronger stub axles, bigger brakes, 5-stud hubs (if desired). Plus FC junkers are often available cheap now. I got the whole subframe from a s5 turbo with rack, struts, hubs etc for AU$300 (US$220). I'm keeping the power steering and instead of the standard belt driven pump, will be using an electric hydraulic power steering pump from a Holden Astra (similar system to the Toyota MR2 pumps people often use).

 

Its a shame the Re-Speed kit no longer exists. I find the only thing I find myself wanting on the car is rack and pinion steering. I'd be happy with it stock beyond that. It would be awesome if someone stepped up and made a kit to bolt (or weld) to the stock subframe, and retain the factory geometry aside from adding a rack, ideally a quick ratio manual rack like the one Re-Speed did. I'd like to keep my car as FB as possible, even despite it's flaws. I know the Re-Speed kit converted to front-steer and included a modified subframe, but still would have been a good option if it existed still. Seems like there would be a lot of interest if someone stepped up and made a kit, that'd be awesome in my opinion. I know I'd be happy to spend money on a quality kit that keeps the car close to stock beyond that.

For me I'm continuing to try and improve it as much as possible as I restore the front end of my car. Not perfect, but getting better and it does add some character to the car, nevertheless.

 

I don't know about that. I actually think an FC setup is superior to the RE-speed kit due to the extra stability and bracing from the subframe, slightly wider track, better mid-mounted engine setup, easier brake upgrade and the wider possibilities for aftermarket coil overs and adjustable steering knuckles. That and the RE-speed kit was LHD only and was designed around the rack was virtually non-existent outside North America. What the REspeed kit really had going for it was the fact it was bolt on, maybe the quick ratio rack and the fact it will work on earlier front-mounted engines (which a FC setup will not).

 

That's basically what I was getting at, I can't really comment on the technical merits of one setup versus the other, but I know if I wanted to go down the rack & pinion route something like the RE-Speed kit would be how I wanted to do it.

I like keeping the stock suspension setup (even if inferior), and the idea of getting a quick-ratio manual rack. I also plan on keeping my 12a for as long as reasonably possible. My car is low miles, and all stock, so I'd like to keep it that way, but rack & pinion would be a seriously good mod since restoring the stock system seems kind of like a dead-end. Replacing the steering linkage did have good results for me, but perfect would be nice, which isn't possible I fear. Not the end of the world, but tight communicative steering would really complement the car overall.

 

I remember seeing this build page a while back, but it appears the hyperlink no longer works. I was wondering what you did for the intermediate shaft and steering column? Thanks!