Steering & Brakes...Notes from the Road & Track Article.

[freds]

There has been a lot of "traffic" in the threads on DEPOWERING THE RACK and ABS or NOT.

I take it from the R&T article that the steering was depowered and the pinion was locked or welded up to get rid of the slop (as they put it).
R&T "Steering is direct and slop-free, directing the 818’s low-sniffing nose with inch-level precision without power assistance."

Also there was no ABS
R&T "The brakes, too, are entirely unboosted, requiring significant pressure but delivering trustworthy feedback up to the locking point."

It was an 818R, I know. I'm guessing FFR's 818S will be the same on these two points.

[Xusia]

Although I don't think we can know for sure yet, the prevailing thought is that ABS can be retained if desired. If possible, I plan to keep the ABS even though I love the feel of unboosted brakes (it won't be a track car, so safety first!).

[RM1SepEx]

Metalmaker12 is looking at my extra pinion shaft, I've played with mine a bit. It doesn't appear to work like the Miata unit... It uses that pinned inner torsion shaft to deflect to work the orifice to flow PS fluid. It doesn't have that little "slop" that can be felt when you de-power the miata rack. I don't think welding the pinion will be needed (at least with the 05-07 WRX rack with the molded in aluminum ear mounts) the earlier racks look different. I put it in a vise like the short video in the depowering the rack thread... no obvious "slop"

My daughters 91 de-powered Miata... you can feel the slight, off center, "slop"

[freds]

Metalmaker12 is looking at my extra pinion shaft, I've played with mine a bit. It doesn't appear to work like the Miata unit... It uses that pinned inner torsion shaft to deflect to work the orifice to flow PS fluid. It doesn't have that little "slop" that can be felt when you de-power the miata rack. I don't think welding the pinion will be needed (at least with the 05-07 WRX rack with the molded in aluminum ear mounts) the earlier racks look different. I put it in a vise like the short video in the depowering the rack thread... no obvious "slop"

My daughters 91 de-powered Miata... you can feel the slight, off center, "slop"

Thanks RM1. There is quite definitely "slop" in the 06. If you clamp the pinion gear tooth end and twist on the upper shaft (that the steering column connects to) with a pair of channel locks....you can feel the slop, and see it in both clockwise and counter c. The torsion bar doesn't require much force to twist. With the leverage of the steering wheel radius, I think it would feel pretty similar to what you describe on the Miata. This photo shows exactly where the relative twisting movement happens.

Valve Details.jpg

I'm glad MM12 is looking at the one you sent him, and looking forward to hearing what he finds.

fred

[metalmaker12]

I have inspected, conferenced with other tuners and reviewed articles on the 05+ pinion. There is about 1/16th -1/8th slope, will we feel it, slightly. So I have the pinion and there is a locking pin that is pressed into the neck. I attempted to hit it out, but that does not seem to work, so I am going to set it up in a drill press and drill it through to see if we can get two halfs. The thing is, even if I do get it in two, there is really no way to weld the two halfs together at and around where the bearing is, so this might be fruitless. Another thought or option is to drill 1/4 holes all around into the pinion shaft behind the bearing location and plug weld them. make sure to counter sink the holes so you can get in there with your tig torch. This might make the shaft more solid an free up some slop. I am also going to maybe drill and plug weld other spots. I am going to try this over the next couple weeks, been very busy at work and around the house with yard work, but I am not forgeting about it, and I will get it done. BTW Fred, a friend did epoxy his, and it held up for awhile, but finally came loose recently. I think drilling and plug welding should work to eliminate slop. We will see

[freds]

I have inspected, conferenced with other tuners and reviewed articles on the 05+ pinion. There is about 1/16th -1/8th slope, will we feel it, slightly. So I have the pinion and there is a locking pin that is pressed into the neck. I attempted to hit it out, but that does not seem to work, so I am going to set it up in a drill press and drill it through to see if we can get two halfs. The thing is, even if I do get it in two, there is really no way to weld the two halfs together at and around where the bearing is, so this might be fruitless. Another thought or option is to drill 1/4 holes all around into the pinion shaft behind the bearing location and plug weld them. make sure to counter sink the holes so you can get in there with your tig torch. This might make the shaft more solid an free up some slop. I am also going to maybe drill and plug weld other spots. I am going to try this over the next couple weeks, been very busy at work and around the house with yard work, but I am not forgeting about it, and I will get it done. BTW Fred, a friend did epoxy his, and it held up for awhile, but finally came loose recently. I think drilling and plug welding should work to eliminate slop. We will see

Go for it. I think you will have to grind through the outer body, it is hard!..... and welding might damage the metallurgy which could lead to cracks and fatigue failure. Who knows....?

Question: What year was the assembly your friend epoxied? I can't imagine the fully epoxied spaces in the 06 "coming loose", but..... if it ever does, at worst it will have the "natural" slop as if I had done nothing so I'm not too worried about it. After that I could still pull it and grind/drill and plug weld. So I'm relaxed about having fully filled my replacement with epoxy.

Anyway glad to get your feed back so far ....And yes that pin is in solidly...as you know I couldn't get mine out either.

[metalmaker12]

It was a 2006, but yea I mean I am only doing to to know if it can be done, not to worried about it if someone left it alone, cause it still would be fine. I guess with epoxy it actually takes serveral momths to fully cure, and temperature differences can effect it. I also have a local shop that epoxyed one and it has held up so far, so it is a good option, I just personally think plug welding, if it does not damage it will be the longest lasting solution. This topic just shows how bored we all are and how bad we need our kits lol.

[Samiam1017]

Metal maker can you drill it in maybe three spots and just tap it and put in some set screws.

[freds]

+1 for "shows how bored we are...." It is quite trivial.

Anyway, good luck making holes in that thing, as I said..."it is hard!"

[RM1SepEx]

Control Valve .jpg

I wouldn't expect epoxy to work well, the torsion shaft is relatively smooth, nothing to grip to. If he can somehow reduce the length between where it is pinned and where they are reconnected the twist allowed will be reduced. Put one in the center, 50% reduction. I'm thinking drilling and pinning or drilling and plug welding...

You can see on this drawing that there is quite a bit of length to the inner torsion bar. you can see it is connected to the steering shaft with a hardened pin. It needs its effective length shortened by connecting it to the rotor. Another problem is that the torsion bar has a slightly reduced diameter when it goes through most of the rotor. You can't just use a pin as it will be subjected to shear (where a hard pin is strong) and bending, where it could fail. If there was a tight fit a pin would be a good solution... the pin can't be too large a diameter, the torsion shaft might break!

The epoxy would be used to fill this space... the problem here is that it is a turned shaft and doesn't have a good surface to grab to that would stop the shaft from twisting...

Plug welding would be best as it would fill in some of the area between the shaft and the control valve assembly. My problem, I'd need a 3/8 hole to do a good plug weld with my MIG !!! Drill through the sleeve and the rotor, to access the torsion shaft... plug weld the two together. You might be able to do it only 2 -3 inches from the attachment around the bearing area

The torsion shaft is most likely splined at each end and the pin only serves to keep it from being pulled out.

[Ironhydroxide]

sounds like i'm gonna have a fun time cutting up one of my spare GC racks. (pre 02 impreza)... just cause this whole thing has intrigued me greatly.

[RM1SepEx]

The more I think about it, I think you may not have that same on center feel... I'm not expecting any slop on center like the Miata rack. It freely rotates for a very small amount of rotation and then locks solid. That's why when on center you can feel a slight slop as the wheel turns with no resistance until the two parts stop relative movement and it turns as one, until you turn the other way, it flops back to the opposite locked up position

What you can expect is some softness in the rotation

as you rotate the wheel due to the force on the tires due to weight on the car the wheel turns a slight bit more that the rack gearing would indicate, it doesn't freely rotate from stop to stop opening and closing the port with the PS oil flow orifice like the Miata design, it more gradually opens and closes the port due to the twisting as a load is added, while it is twisting to expose the port, the wheel is still turning, so there should be none of that dead feel when you go left to right etc...

if you want to make it as direct as possible you need to virtually eliminate the ability for that torsion bar to twist, find a way to shorten its effective length. As it shortens up the twist in degrees per load applied will reduce in proportion to the length. The other options are to make it either larger in diameter or out of a stronger material...

I'm now thinking that we will be pretty happy with it in as stock condition... If I can comfortably drive my Daughter's Miata with the on center slop, I can drive with the torsion bar setup...

For the best "feel" though a way to stiffen up that bar's twist should be the way to go

[freds]

We are still having fun with this topic!

Have to add:
1. The 06 valve is considerably different to the cut-away posted by RM1. It has no bearing below the lower oil seal, and is generally slimmer. I have not found a cut-away of the 06 yet...and I have searched! Also the upper bearing is integral with the sleeve on the 06. On the one in the diagram posted the external housing splits so that the internals can be removed "downwards", as I see it. Admittedly, I have not held one or worked on one to be sure of this

2. The epoxy, as I envisage it, is to fill the spaces between the male and female splines (or whatever form the positive stops are), to eliminate the slop. I think there has to be a positive stop (left and right) in the design so that even if the torsion bar were to break you could still steer. Filling all the internal spaces might add some adhesion between parts, but compression loading between splines is, I believe, the low risk slop remover.
The torsion bar is there to add some progressive "feel" and to allow the valves to operate in a gradual way...as opposed to snap "on" and "off" as well as to center the valves (both left and right) to return to centered "off" when no torque is being applied to the steering wheel.

These devices (all of them) are very clever!

[metalmaker12]

I am going tear into in a couple days, it will be posted on the depowering thread.

[longislandwrx]

good luck. so 05 had the change? I was hoping my 05 would be easy.