Fiero

I'm not sure if exactly what I'm doing has been done before, so I figured I'd share.

Background:
When I bought my car, the inside tire wear was noticeably bad, it wouldn't track and it was pretty darty in general despite having been aligned after I had replaced much of the suspension. I finally traced the problem to what appeared to be a worn steering rack bushing (part 10, in the diagram below). This made sense as the tie-rod end had obviously been replaced and whatever monkey had done it fucked up the boot while in the process. So the bushing probably filled with road crap and wore out. To replace the bushing, I'd have to drop the rack, and essentially rebuild it - so I figured, 'f-it, if I'm going to have to drop the rack anyways, let's upgrade'.




Choices:
I knew I wanted something with a lower steering ratio, even driving around town in the D-Slo S, I noticed you really work the steering wheel for even mild turns. With my intentions to eventually autoX the car, I doubt I could move the steering wheel fast enough to post even ball-park competitive times. I researched my opinions and found only two:

For reference, the Slo-S's rack is 4 turns lock-to-lock (L2L).

Quife Kit - rebuild old rack housing, put in Quafe pinion/rack - net result: 3.25 L2L
Pros: Light, fresh rack when done, easy "bolt-in"
Cons: Cost ($239 list + seals), if I don't like it I'm stuck with it

GSR P.S. Rack - find a rack off a GSR, remove the power steering and adapt it for the Slo-S - net result: 3.0 L2L
Pros: Quicker ratio then quife kit, cheap, could convert to PS if ratio not manageable in autoX's
Cons: Custom setup, weight hit due to PS components not used

Decision:
The GSR rack seemed to be the most versatile decision and worth the weight hit for the slight performance advantage to the Quaife kit. Also it's cheaper!
So I'm going that route.

Current Progress:
I bought a used GSR rack for $60 then replaced the boots (Cost about $30), luckily the tie-rod ends still look pretty good. I've heard the GSR rack does not in fact bolt up to the 92-95 EG-style subframe, but given the sketchiness of the OEM honda mount (U-bolt), I figure I will either machine a new bracket or weld in a new pick-up point for the GSR bracket. If worse comes to worst I should be able to just swap in a GSR subframe, so I'm not all that concerned about the fitment at the moment.

To covert the GSR rack to be powersteering I was going to use a similar method to this thread:
https://honda-tech.com/zerothread?id=184202
But after some pondering, the above mod seems extremely inefficient. So instead, I've decided to use my project as a guinea pig for a new method of bypassing power steering.

I'll use some pictures to explain:

Here's a normal powersteering rack (thank you HowStuffWorks):


PS fluid is controlled by the rotary valve at the steering column and used to push the piston built into the rack to compliment the drivers steering force.


Here's the "Realtime racing Mod":

Now instead of the piston aiding the driver, it's actually creating a resisting force. In addition to having to steering the car, the driver is having to redundantly push fluid and air through the rack's fluid plumbing.


Here's my method:


Now the piston chambers are connected to one another, bypassing the rotary valve altogether. This should be the routing of least resistance for a looped PS system. In theory this routing should perform better then the Realtime racing method as the fluid (air/oil) has to travel less and is less likely to build resisting pressure across the rotary valve. The rotary valve's ports have been sealed with fluid to prevent damage caused by corrosion/debris.

As a bonus, with my method, you avoid some of the more expensive Aerotek fittings or large AN fittings used in the Realtime racing variants. Instead I'm going to do my routing with cheap AL AN-4 fittings. The most expensive components so far have been the plugs for the rotary valve which are pretty difficult to find metric sizes (~$18 in plugs).

Currently the parts are in transit, I'll post a more detailed how-to once I'm done with pictures/prices/vendors/review of functionality.

Feedback is definitely welcome.

instructor74

You are correct and incorrect about the integra rack fitting into the civic. The power stearing rack will bolt in if the car had ps to begin with. If not the sub frame needs a little attention. On the passanger side of the car the non ps cars mount is flat on car with ps that mount has a circular cut out in it to accept the larger dia. rack. I ran into this problem when replacing my damaged subframe I ended up with one from a non ps car. I just drilled out the spot welds and swapped the mount from my sub frame to the new one.

95ProjectEJ1

iTrader: (5)

Thanks for the info. I will need this pretty soon as my PS rack is starting to give me some trouble and has a torn boot. Figured I might as well picked up an OEM GSR rack instead of picking up some rebuilt.

Long Grain Wild

iTrader: (1)

Hey Fiero, If you're really looking to reduce the hydraulic drag, then how about something like this:



More work, but cleaner. Note that I've not tried this and there's certainly bound to be some surprises, but in theory, it should work great.

Fiero

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Long Grain Wild &raquo;</TD></TR><TR><TD CLASS="quote">Hey Fiero, If you're really looking to reduce the hydraulic drag, then how about something like this:



More work, but cleaner. Note that I've not tried this and there's certainly bound to be some surprises, but in theory, it should work great.

</TD></TR></TABLE>

It's true that would be better. The reason I didn't initially want to do this is because of the amount of work involved, I was originally going to just do the same thing as the Realtime racing cars but for the same amount of work as that mod, I could get a better end result using my method. Also, if I did the modification that you're suggesting I would not be able to convert the rack back to PS, and having that option is a major plus as I'm not sure what the steering effort is going to be like, after all I'm coming from the super slow 4 L2L manual rack which can at times be difficult to move (I already bought a pump and the lines, just in case).

You're definitely right though, if I decide that I like the steering effort and want to permanently convert the rack to manual. I would do something like you're suggesting. I'd probably take a step further though and lathe down the piston, mill off most of the rotary valve and weld and shave the fluid holes. In that situation though, most people would just opt for the quaife

Bejita

P.S. You DO NOT have to drop the entire rack to remove the bushing. Just the inner and out tierod ends. I've dont it before.

Long Grain Wild

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fiero &raquo;</TD></TR><TR><TD CLASS="quote">

It's true that would be better. The reason I didn't initially want to do this is because of the amount of work involved</TD></TR></TABLE>

Yeah, I took a look at the FSM after I posted my message and getting that rack gear out of the housing is not as easy as I made it sound. Everything is cake until you have to press the seal out of the end of the housing. And you know what?? That would completely explain why I couldn't get that damn rack gear out of the housing with my bare hands at the boneyard the other day.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fiero &raquo;</TD></TR><TR><TD CLASS="quote">I'd probably take a step further though and lathe down the piston, mill off most of the rotary valve and weld and shave the fluid holes.</TD></TR></TABLE>

Haha! That's funny! That's' exactly what I was gonna suggest that first, but I was trying to keep it to tools that "normal" people have. I've got the required machines in my shop, but I'm not normal. I realize that not everyone is so lucky.

It's still cheaper than the quaife kit, and it's still got a tighter ratio, but you're right... If you're ever going to convert to full PS than you can't go messing with that center seal on the rack. You COULD probably pick up <U>TWO</U> used GSR racks for less than the cost of <U>ONE</U> quaife kit though!!

Long Grain Wild

iTrader: (1)

Fiero,

One other idea... If you drain all the fluid out of the rack, you should be able to simply loop the lines without a vent. The residual oil should be enough to keep the sliding seal lubed and you don't have to worry about the fluid expanding and blowing a seal.



Should be easier to force air through the loop as opposed to PS fluid. Reversible too so if you decide to finish a full PS install, you're still good.

Fiero

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Long Grain Wild &raquo;</TD></TR><TR><TD CLASS="quote">Fiero,

One other idea... If you drain all the fluid out of the rack, you should be able to simply loop the lines without a vent. The residual oil should be enough to keep the sliding seal lubed and you don't have to worry about the fluid expanding and blowing a seal.



Should be easier to force air through the loop as opposed to PS fluid. Reversible too so if you decide to finish a full PS install, you're still good.
</TD></TR></TABLE>

Yeah, that could work too, and that's kinda what I'm going to be doing. I don't intend to actually be passing fluid between the two chambers of the rack. What I'll probably do when I install it is fill it up with fluid as much as I can, then work the rack back and forth real fast while the car is on stands. This will likely force much of the fluid I've put in out of the system, until the fluid level in the rack reaches an 'equilibrium' level. I'm just guessing, but I would bet that the ideal amount of fluid is just under the quantity you'd need to pass fluid through the cross-over.

Also, the addition of a vent is pretty key as its a sure-fire way to assure that you're not going to be building up any type of pressure (air or fluid) in the system. And obviously a pressure differential across the piston is what's going to make that rack difficult to turn.

I love the variants, it's always fun to think about what the best way of doing a mod like this is.

Long Grain Wild

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fiero &raquo;</TD></TR><TR><TD CLASS="quote">

I don't intend to actually be passing fluid between the two chambers of the rack. What I'll probably do when I install it is fill it up with fluid as much as I can, then work the rack back and forth real fast while the car is on stands. This will likely force much of the fluid I've put in out of the system, until the fluid level in the rack reaches an 'equilibrium' level. I'm just guessing, but I would bet that the ideal amount of fluid is just under the quantity you'd need to pass fluid through the cross-over.

Also, the addition of a vent is pretty key as its a sure-fire way to assure that you're not going to be building up any type of pressure (air or fluid) in the system. And obviously a pressure differential across the piston is what's going to make that rack difficult to turn.
</TD></TR></TABLE>

I think you're asking for trouble... The method you described to establish equilibrium is while the car is <U>static</U>. As soon as you're in a turn and all that fluid sloshes to one end of the rack, you'll be passing fluid through the cross-over tube. Worse yet, is that you'll be doing it intermittently which could result in a jerky wheel feel because you'll be passing big bubbles through between slugs of fluid.

I think you should design the system such that you're either passing <U>ALL</U> fluid through the cross-over <U>ALL</U> the time or no fluid through the cross-over <U>ever</U>. I'm no expert, but a half full rack sounds like trouble.

And the addition of a vent should only be key only if you've got the entire system filled with fluid. Think about it... If the system is completely filled with fluid and doesn't include a vent, then the pressure is going to go through the roof when it gets hot because that fluid is non-compressible.

However, if the system is full of air, and that air expands when hot, the static pressure inside the whole system will go up a little, but who cares? The end seals in that rack are designed to withstand the hydraulic load of high pressure fluid when the pump is running... You think they won't be able to hold some air that was put in there at ambient temp and then capped off?

One last thing...

"Also, the addition of a vent is pretty key as its a sure-fire way to assure that you're not going to be building up any type of pressure (air or fluid) in the system. And obviously a pressure differential across the piston is what's going to make that rack difficult to turn."

There will never be any significant differential pressure. HAHA! That's the whole reason you put in the cross-over, remember? Will there be absolute pressure? Yes, but of course, the absolute pressure in the system is immaterial. Differential pressure? No. The cross-over will take care of that, vent or no vent.

Don't worry... I won't spill the beans to your ME prof.

Fiero

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Long Grain Wild &raquo;</TD></TR><TR><TD CLASS="quote">

I think you're asking for trouble... The method you described to establish equilibrium is while the car is <U>static</U>. As soon as you're in a turn and all that fluid sloshes to one end of the rack, you'll be passing fluid through the cross-over tube. Worse yet, is that you'll be doing it intermittently which could result in a jerky wheel feel because you'll be passing big bubbles through between slugs of fluid.

I think you should design the system such that you're either passing <U>ALL</U> fluid through the cross-over <U>ALL</U> the time or no fluid through the cross-over <U>ever</U>. I'm no expert, but a half full rack sounds like trouble.

And the addition of a vent should only be key only if you've got the entire system filled with fluid. Think about it... If the system is completely filled with fluid and doesn't include a vent, then the pressure is going to go through the roof when it gets hot because that fluid is non-compressible.

However, if the system is full of air, and that air expands when hot, the static pressure inside the whole system will go up a little, but who cares? The end seals in that rack are designed to withstand the hydraulic load of high pressure fluid when the pump is running... You think they won't be able to hold some air that was put in there at ambient temp and then capped off?

One last thing...

"Also, the addition of a vent is pretty key as its a sure-fire way to assure that you're not going to be building up any type of pressure (air or fluid) in the system. And obviously a pressure differential across the piston is what's going to make that rack difficult to turn."

There will never be any significant differential pressure. HAHA! That's the whole reason you put in the cross-over, remember? Will there be absolute pressure? Yes, but of course, the absolute pressure in the system is immaterial. Differential pressure? No. The cross-over will take care of that, vent or no vent.

Don't worry... I won't spill the beans to your ME prof.


</TD></TR></TABLE>


Almost... I'm still right though . You have to remember you're going to have a pressure differential anytime you're moving fluid through a constricted passage (aka, anytime you're forcing fluid through a tube, there will be a pressure change). That pressure differential across the piston is going to be your resisting force. If you vent the cross-over you're less likely to develop that differential as the whole system is being kept at ambient pressure.

Also I think you may have misinterpreted me, I don't expect to be passing any fluid through the cross-over ever. The cross-over is just more efficient then two separate vents as any oil vapors are kept in the system to be reused as opposed to just being forced out in to the environment.

No need to tell any of ME professors they'd agree with me, plus I've been working professionally for a while anyways

Long Grain Wild

iTrader: (1)

I understand that there will only be a differential pressure when the piston is moving. We're in perfect agreement there. The problem is this part...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fiero &raquo;</TD></TR><TR><TD CLASS="quote">
If you vent the cross-over you're less likely to develop that differential as the whole system is being kept at ambient pressure.</TD></TR></TABLE>

The vent does nothing to prevent the differential pressure. It simply prevents the buildup of the <U>static</U> pressure. If the vent is centered in the crossover, it should always be at a pressure halfway between the two ends of the cylinder. And if the vent is NOT centered, then you'll have asymmetric forces when moving the rack one direction compared to the other. Maybe if I put some numbers on it, you'll see it:

This: is no different than this: is no different than this:

The differential pressure is exactly the same in all three examples. Vent or no vent. Static pressure offset or no static pressure offset.

If you want to reduce the <U>differential</U> pressure you need to increase the orifice size, not add a vent: