Special Projects - Electro Power Steer

[Mohudsolo]

Karcepts, why would you want to mount the pump in front of the transmission? Putting it there defeats one of the reasons to bother with the electric pump, being able to keep the weight behind the axle. It's lower than a stock pump which helps some, but on the floor or firewall is better IMO.

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[Karcepts]

Originally Posted by Mohudsolo

Karcepts, why would you want to mount the pump in front of the transmission? Putting it there defeats one of the reasons to bother with the electric pump, being able to keep the weight behind the axle. It's lower than a stock pump which helps some, but on the floor or firewall is better IMO.

I totally agree with desiring weight more rearward but there is very little room on the firewall area with a K-series unless you have your battery relocated and have a RHD like Kiwi where you don't have a brake master cylinder and booster in the way. It could mount on the other side of a LHD master cylinder/booster, but the weight would be very high to avoid transmission interferences and the bracket itself would have to be substantial and gusseted due to overhung loading from the nearest available mounting location. This was the most logical mounting position for my scenario. The electric pump in this location is no more forward than the belt driven unit you are removing, it is located ~12" lower, and requires a simple 1/2 lb aluminum flat plate to mount instead of a potentially heavy steel gusseted bracket if trying to form it around a brake master cylinder. The main reason to bother with the electric pump for me was to free up some extra HP. The mounting position relative to weight displacement is still an improvement over the stock belt driven unit, so it isn't proving to be disadvantageous in any way. The car I am mounting this in isn't really an all out race car; so yeah, if you don't mind throwing it inside and mounting it on the floor with you, then I agree, that would be a bit better.

[Crx Jimmy]

Originally Posted by ED9man

There are hydraulic lines running into the speed sensor that sits on the diff from the rack that control the pressure based on speed.

This is only on the cable b-series tranny's in the 88-91 crx/civic(jdm edm) and the 90-93 integra. they utilize a different pump as well. this doesnt apply to most of the cars in question which seem to be eg/ek's

[rotten]

Originally Posted by ED9man

There are hydraulic lines running into the speed sensor that sits on the diff from the rack that control the pressure based on speed.

Yes, but get this: basically its a little pump. If you block off that line going into the rack's pressure sensor/switch, it simulates speeds in excess of 30 MPH. So basically the amount of assist on those racks is variable up to 30 MPH and then is the same from 30 MPH onwards.

By eliminating the VSS hydraulic lines (like in a OBD1 motor & trans in a EF) you're basically underboosting the rack slightly, which is exactly what we'd want. Certainly better than having parking lot amounts of assist while going 60!

I was surprised to see that there is not boost difference on the rack after 30 MPH. I thought it was variable up to perhaps 60MPH or more. I suspect that actually the difference between 0 and 30 may be smaller than I'd original thought as well.

This is great news for me because it simplifies the power steering conversions on EFs.

THe other side of this is that on the EFs you could also use the stock VSS hydraulic lines to control the amount of assist you're getting from an electric pump. THe pump can put out full pressure, but the rack would meter what it needs based on the VSS.

[ED9man]

So you are saying it boosts less from 0-30 and more from 30 on? That doesn't seem to make sense. Or when you block the line it boosts as much under 30 as it does from 30 on? I would think that it would up the assist under 30 and have it plateau above 30? Also I am wondering if the VSS is beneficial because it controls the boost in the rack regardless of pump output, I am wondering if Toyota pump runs at a higher pressure/ moves more fluid and would cause the rack to be overboosted without something that keeps it in check?

[RagingAngel]

rotten is simply stating that the boost from 30mph onward is constant and lower.

Below 30mph it has a higher level of boost.

If you block off the EF's VSS hydro lines, you have constant under-boosting.

[rotten]

Originally Posted by ED9man

So you are saying it boosts less from 0-30 and more from 30 on? That doesn't seem to make sense. Or when you block the line it boosts as much under 30 as it does from 30 on? I would think that it would up the assist under 30 and have it plateau above 30? Also I am wondering if the VSS is beneficial because it controls the boost in the rack regardless of pump output, I am wondering if Toyota pump runs at a higher pressure/ moves more fluid and would cause the rack to be overboosted without something that keeps it in check?

Basically what Raging Angel sez. It gives more assist/boost at slower speeds up to 30 mph, where it flattens out. Blocking the VSS line simulates an over 30mph condition--basically underboosting at slow speeds, which is perfect for what we want.

I actually suspect that the difference between low speeds and high speeds may not be as much as it seems like it would be.

You're right about the VSS stuff--it basically is a little pump that builds pressure to a pressure release valve in the rack itself. It would function the same with an electric pump or the stock belt-driven unit. So at least on the 90-93 Integra racks (with the 4 ports) you should not get an overboosted scenario even if the Toyota/Subaru/Mazda whatever electric pumps provided more pressure than stock pumps.

[soulpwr]

[SkankyEJ7]

looks like i may need to hit a junkyard or too to find me a mr2 ps pump

[drmikey]

I've been using this setup on my K20 EK for a couple of years now and it is excellent - although I added a 4QD speed controller to adjust the assistance pressure and also does away with the need for a high power relay.

But I now have this system for sale as I'm now racing and have to go as basic as I can. I'm after $400 and includes

MR2 pump
Custom lines
Resevoir bottle
4QD controller
All wires

[rice r0cket]

Has anyone considered an electric rack from the NSX and S2000?



It adds a couple lbs to the rack, but eliminates the pump and all other associated hardware. Basically half the rack gear is a worm gear, and a motor sits around it driving it.

[Ramirez428]

would it even bolt up to eg/dc ek?

[ErrDizzle]

nope and you need a module and sensors to control the motor. it would be great if everything was self contained and only required power wires.

[Jaker]

Originally Posted by ErrDizzle

nope and you need a module and sensors to control the motor. it would be great if everything was self contained and only required power wires.

Why the need for the module/sensors? I haven't done any research, but from the look of that picture, there's a steering universal shaft sticking out of the rack.

[ErrDizzle]

hhmmm ok. it just looks like a steering rack with a dc motor on it. so whats going to control the motor? whats going to sense which direction to steer or how fast the steering wheel is being turned, how much assist, which direction to assist, or even how much assist to use when at high speed, etc.

it's easier to use a normal ps steering rack and just add an electric pump for our cars because the valve body on the top of the rack that connects to the pinion already figures out how much assist, which direction, etc.

[Jaker]

How would it be any different to have the sensors built into the rack, and feed the input from the steering wheel via the steering column to these sensors versus having the sensors in the steering column up by the steering wheel?

EDIT:

I've done some research now. The S2000 uses the electric power steering rack, a rack mounted "torque" sensor where the steering shaft/column attaches, a power steering control module, and signals from the speed sensor and the tach. I think the speed signal needs to be the same high frequency signal that everyone pines for to permit the use of the S2000 cluster in EKs, EGs, etc... but we all know there are signal converters out there. Now the only parts left are mounting the rack in your chassis, and adapting the tie rods and the steering column attachment.

Sounds like it could be a little simpler than the MR2 power steering pump, assuming the rack mounting can be done without too much hacking. I think I might give this a try.

Anyone interested in all the MR2 power steering system components, except for the steering column sensor? I have the pump, the controller, the power relay, a bunch of wire attached to the appropriate plugs, and some sections of the power steering lines for fittings.

EDIT #2

Scrap that idea. The S2000 is a front steer car. The damned rack will make the wheels turn the wrong way.


Modified by Jaker at 8:39 PM 8/2/2008


Modified by Jaker at 8:42 PM 8/2/2008

[ErrDizzle]

how about a rhd s2k rack mounted backwards.

[Jaker]

I've been thinking about that. Haven't given it enough thought yet though.

[rice r0cket]

http://www.jtekt.co.jp/e/products/steering01.html

HMMMMMM...

[stealth50k]

Anyone know where to buy the fittings for the hoses and the hoses themselves. A website or something would be cool. thanks

edit:
I found some good sites with the hoses and fittings for this job.

http://store.summitracing.com/...XID=5

http://www.racerpartswholesale...tings




Modified by stealth50k at 4:46 PM 8/12/2008

[ShagNastyEK9]

Originally Posted by drmikey

I've been using this setup on my K20 EK for a couple of years now and it is excellent - although I added a 4QD speed controller to adjust the assistance pressure and also does away with the need for a high power relay.

But I now have this system for sale as I'm now racing and have to go as basic as I can. I'm after $400 and includes

MR2 pump
Custom lines
Resevoir bottle
4QD controller
All wires

Great price, if i had the money to spend, i would jump all over it, these pumps are hard to find used, and not cheap new, sure it will sell

[kommon_sense]

I bought mine from http://www.anplumbing.com . However having done this now, I don't like the Earls high pressure hose. Its very difficult to work with and has a cloth/fabric coating that stains very easily. If I were to do it again, I would try russell or aeroquip.

Originally Posted by stealth50k

Anyone know where to buy the fittings for the hoses and the hoses themselves. A website or something would be cool. thanks

edit:
I found some good sites with the hoses and fittings for this job.

http://store.summitracing.com/...XID=5

http://www.racerpartswholesale...tings


Modified by stealth50k at 4:46 PM 8/12/2008

[BlackDog914]

Jaker ... I'd be VERY interested in buying the MR2 pump and bits that you have... I've just joined the forum and am restricted from PM'ing ... so... if you could e-mail me at jim@island.net maybe we could go from there... I'd also like to hear from DrMikey on the 4QD controller idea..

thanks
Jim

[Jaker]

Originally Posted by BlackDog914

Jaker ... I'd be VERY interested in buying the MR2 pump and bits that you have... I've just joined the forum and am restricted from PM'ing ... so... if you could e-mail me at jim@island.net maybe we could go from there... I'd also like to hear from DrMikey on the 4QD controller idea..

thanks
Jim

Hey Jim.

Thanks for the interest, but I won't be doing anything anytime soon. Since I realised the S2000 is front steer (rack resides ahead of the front wheels in the chassis), and I can't use a LHD rack (the wheels would go the wrong way), I have to come up with a better idea (maybe a RHD rack flipped around).

I'll keep you in mind if I do come up with a solution.

[JOEY F.]

Wow, this is awesome. Id def be up for buying a kit when it comes out.