Donor parts list, first draft thoughts

[scartaan]

I am assuming that the steering rack will be used without power assist. Therefore one can remove the power steering pump from the engine along with the AC pump and all that goes with them. Do all agree?

[skullandbones]

It may be more doable for this project since the weight on the front wheels is quite a bit different than in a roadster which is my present project. However, based on the general concensus of the roadster crowd, the use of a power rack without the pump is not ideal. I believe the power rack will perform much as designed with the pump and may not do as well unhooked. Here's my reasoning for either project: how can you maintain the rack properly? I think it is pretty much self maintaining when PS fluid is coursing thru it but I don't think it is really designed to go without that constant bathing of lubrication. Just as in the roadster applications, it's probably a better and not so expensive upgrade to go with a manual rack if that's what you want (about $100 for a manual rack). IMO WEK.

[el_jefe]

I haven't done it with a Subaru (that I recall), but it's common in track cars to fill the rack with fluid and cap it where the lines would go in. Plenty of lube, no parasitic loss.

[skullandbones]

That's exactly the same solution I have heard of for the roadster application. I just have heard some discussions that favored the power rack being used with the pump. It's hard to say but it could be for street situations where such as slow or from stop turning, parking, etc. that it doesn't work as well. In a track environment, those situations would not be an issue. I was definitely thinking about that for a long time but finally "chickened out" and went with a pump. I really think the lighter front end could make a difference, too. WEK.

[el_jefe]

Over 5mph it's not bad, I've driven a bunch of different cars that have been converted over to a manual rack. It shouldnt be THAT hard to run longer lines up to the rack if you want to keep the power steering. Parasitic loss doesn't bother me much (just add more boost!) unless you are running a spec race series. High rpm shenanigans can cause problems with throwing belts occasionally, but again that's more of a track problem.

[Evan78]

Miata guys "de-power" their racks pretty frequently. On the Miata, the power steering rack is a quicker ratio, so some prefer that over just using a non-PS rack. Here's a how-to from a reputable Miata parts company:

http://www.flyinmiata.com/tech/depower.php

And another by Dave Coleman, currently a Mazda R&D engineer last I heard:

http://www.motoiq.com/magazine_artic...ring-rack.aspx

[RM1SepEx]

I haven't done it with a Subaru (that I recall), but it's common in track cars to fill the rack with fluid and cap it where the lines would go in. Plenty of lube, no parasitic loss.

a better option is to take the rack apart and reconfigure it by removing some unneeded parts and make it a full manual rack. very common mod in a Miata as most of them come with a power rack and the power rack has a faster ratio and is preferred when converted. If you fill it and loop the lines it will have more friction than needed.

I guess it is prudent to read to the end before posting!

[PhyrraM]

There are also electric power steering pumps that can be sourced and mounted up front. Should be lighter then long PS lines to the back that are filled with fluid. The '88-'91 Subaru XT6 is one, I'm sure there are others.

[305mouse]

Didn't the mr2 have an electric pump?

[RossLH]

Over 5mph it's not bad, I've driven a bunch of different cars that have been converted over to a manual rack. It shouldnt be THAT hard to run longer lines up to the rack if you want to keep the power steering. Parasitic loss doesn't bother me much (just add more boost!) unless you are running a spec race series. High rpm shenanigans can cause problems with throwing belts occasionally, but again that's more of a track problem.

On a WRX, as long as there's fluid in the rack its fine. Heavier of course, but still driveable. If there's no fluid, the car isn't driveable. I had the misfortune of experiencing this on the highway--changing lanes at 70mph was a chore, taking a turn at 25mph required both hands and most of my weight, and below 5mph that wheel was not about to turn. Though it would be an interesting experience to take the inner seals out and try again.