Kahren

iTrader: (13)

stock manual rack is 20:1
na power rack is 17:1
turbo power rack is 15:1

i find the 20 to be too slow and the 15 too fast, convert the 17 to manual and you should like it.

SonicRaT

iTrader: (6)

Yeah.. 15:1 non-assisted SUCKS at a tight track, having to brute force that wheel around while shifting doesn't make for a very good run.

coldfire

iTrader: (1)

i have the stock NA PS rack right now, so 17:1?

yeah, i'm definetly concerned that there will be considerable effort with my 225s up front if i went with the 15:1 rack.
thanks for mentioning the 17:1 as a good choice.


so i guess this is a big fat NO to an aftemarket manual steering rack? no body makes one?

although now i'm quite interested in the de-powering modification posted above.

Snrub

iTrader: (1)

I'm sure you could do some custom job. eg. CP Racing has their FB rack and pinion conversion kit, perhaps they could make one for you that would work in a FC. I'm sure the price would not be friendly.

Icemark

No that is wrong. Did you not see what was posted in this thread above your post???:

So, let make it even more clear:

all the manual racks that are designed for the FC are 20 to 1

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, 88-89 vert that were equipped with power steering came with a 15.2:1 ratio.

The 17.4:1 came on the 89-90 GTUs, 90-91 Infini, 91 coupe, 90 GXL, 90 GTU, 90-91 Vert).

coldfire

iTrader: (1)

Mark, how does that apply to the Canadian models?

did the base/ GX model here receive the 17.4:1 PS rack?

Black91n/a

I did the depowering of the steering rack today along with the energy suspension bishing install on the front. I can report that the procedure outlined on Flyin' Miata's site (link on page 2 of this thread) is nearly identical to what needs to be done to an FC's steering rack, and can be used as a guide for you all to do this. There are a few small differences. First of all there is no large barrel supporting the shaft in the middle, there is a locating bushing at the end of the shaft though. The seal that needs to be removed is the same though. The ring that holds the part on the end of the rack that prevents it from being removed doesn't get punched out, just rotate the housing counterclockwise and it should unwind from the housing through the slot then you can take the ring out completely. There is great difficulty in removing the rack from the car, and I'd reccomend getting the pump and braketry out of the way first, that way you can get at the lines that much easier. Also, no mater how much fluid drains from the rack, there always seems to be more in there, so be ready for that. I ran out of time to put it back in tonight as I started later than planned, but it's ready to go back in, I'll get it back in tomorrow and take it for a spin to see how it feels. Afterwards I'll post my thoughts on how it feels.

This is no trivial job, it took me about 3 hours to get it out, dissasembled, modified and put back together, and that's with a large selection of tools and air tools to help me along. It'd be alot easier to loop the plumbing and get as much fluid out as possible and take the pump and braket off. But if you want to do it right, you should do it this way.

I just may have the very first RX-7 to have this particular mod done! Woooohoooo! My car's now got even more unique features (I have a custom built by me fresh air headlight cover).

Icemark

I would expect that the S4 Candian would follow suit as the US spec (either a 20:1 manual rack or a 15.2:1 power rack.

As far as S5, it is my understanding that the GX was the same as our GTU in S5 models

Black91n/a

Well I got the car put back together this morning and took it out for a drive. For the record I've got 225/45/17 Falken FK-451's on 17"x8" mustang GT wheels that have a 32mm offset with a 17.4:1 steering rack. Other setups might feel different due to different offsets, widths and tires. It felt fairly heavy at low speeds (like parking) and when you go hard into a corner you can really feel the tires loading up, but that's what you want to feel. During normal driving you won't feel a difference except in parking lots, so it'll be very livable on the street. It gives MUCH better feedback to the driver on what the front tires are doing. For autocross it'll be a little heavy for the tightest of corners, but most of the time it'll be fine (that is if you have half decent upper body strength). I'm quite happy with this mod as it cost nothing, gave a big improvement in feedback, took a fair chunk of weight off the front left corner, feed up a lot of space beside the engine, and will be perfectly suitable to run on the street. I would NOT reccomend this for one of the faster 15.2:1 racks as the effort required to steer would be too much.

Black91n/a

Just to let you know I posted a how to.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/how-de-power-your-steering-rack-right-way-439979/

coldfire

iTrader: (1)

wow, thanks a lot man, that's great to hear

i'm going to pick up a spare PS rack and try this modification on it.

Icemark, any idea how you can identify the different rack ratios? i mean, besides mesuring lock to lock while the rack is in the car...

- Aaron