Special Projects - Electro Power Steer

[KIWI]

SPECIAL PROJECTS MOTOR SPORTS Electro-Hydraulic Power steering conversion: This is not an original idea… Credit goes to Derek from Hondata who did the swap before me. I acknowledge many of his findings and quotes. This outlines the adaptation and fitting of a Toyota MRII Electric Power Steering unit to our DC2 Integra Racecars. This system uses an electric motor to drive a hydraulic pump which in turn provides hydraulic pressure to the conventional Honda power steering rack. We have refined this swap and we will be producing a complete bolt on kit in the near future. The reason for this swap is twofold: (A) to reduce the Horsepower drag from the engine driven power steering pump. On an engine Dyno the stock DC5 ps pump and rack uses 8.5 hp peak, while in a straight ahead position. On a lower powered B series the loss was 5 hp peak. The power loss from EHPS is between 0.25 and 0.75 hp (via the alternator), depending on steering load. And (B) The reason I wanted the power steering at all is that after over thirty years of International Touring Car Racing, I have found it is faster around a race track than with manual steering. The lap times of a high powered front wheel drive racecar with a lot of castor, will improve if driver fatigue is reduced. Call it old age if you like, but I prefer to finish an event not feeling like I have just survived the fight of my life. Note that this form of electric power steering is not the same as EPS, as used in the S2000 and EP3 Honda Civic, which used an electric motor directly on the steering rack, with no hydraulic fluid involved. Disclaimer: This information is provided for those interested in performing the same installation as me. I have tried the vehicle at race speed, it works, and I am completely happy with the results. If you do want to perform the swap, all the information I have is on this page – And will be provided in step by step detail with a purchased conversion kit. If you are not mechanically or electrically competent, then this swap is not for you. The Conversion: The main component is the motor/pump assembly. We used the motor/pump from an early ‘92-‘93 MR2, which used old technology (brushed DC motor, vane oil pump) which was perfect for our purpose. These are available for around $150-$200 used. The pump has a pressure adjustment screw, so matching the pressure to the rack requirements is quite easy. (See Pic. 5) All you need: 1 - Good Used Toyota MRII Pump. 1 - High pressure hydraulic line with Dash - 6 female fittings on either end. 1 Straight and 1 90 degree bend. 1- Fabricated bracket to mount the pump. 1 - Dash -8 Low pressure fluid line with Dash -8 Female fittings on either end. 1 - 1/2” or Dash -8 Low pressure fluid line from Pump to reservoir. 2 - ½”to 3/4” Hose Clamps for low pressure line from Pump to reservoir. 1 - Fitting Dash -6 Male to 16mm x 1.5 1 - Fitting Dash -6 Male to 14mm x 1.5 1 - Fitting Dash -8 Male to 16mm x 1.5 1 - 80 AMP Circuit Breaker 8 Gauge wire. Soldering equipment and wire ends Hydraulics: After we had decided on the best place to locate the electric pump- We laser cut a stout 3/16” bracket that bolts under the Top Control Arm nuts on the top side of the Strut and allows the pump to be suspended alongside the strut tower. In our case as we are K-20 powered, the left side afforded the most room. However, with a B series engine, the right side will be better. (See Pic 1) We then mounted an after market fluid reservoir on the fire wall taking care that the lowest point of the reservoir was above the electric pump. (See Pic. 2) The hydraulics is fairly straight forward. The pump outlet was a 16mm thread with a 10 mm hard line, and the steering rack was a 14mm thread with 8mm hard line. (See Pic 3) Rather than use the hard line which was too hard to bend and shape, I went to a Hydraulic hose specialist and had a flexible high pressure hose made up with the correct fittings on either end. I used A -6 Male to 16mm x 1.5 adaptor into the high pressure Pump outlet, and a -6 Male to 14mm x 1.5 adaptor into the Steering Rack pressure outlet. I have fitted this system to both my US Spec. Integra and my JDM Right hand drive car, so make sure you double check your Fluid line lengths before you get them made up. The pump suction side used a hose fitting which was identical size to the Honda fluid reservoir, so no problem finding some hydraulic low pressure hose for the Pump to the reservoir. By holding the pump assembly in a vise, using a large Crescent Wrench you can carefully rotate the pressed in - low pressure hose fitting so it points at a 90 angle to the vertical pump when mounted, according to where you position your reservoir.(See Pic 3) For the low pressure return line from the steering rack, I used a -8 Male to 16mm x1.5 adaptor. I made up a -8 braided hose with -8 Female fittings on each end to connect the low pressure Steering rack outlet to the -8 Male fitting on the inlet of the reservoir. (See Pic. 4) As the complete systems fluid capacity is almost double that of the OEM Power Steering system, so far I have not found the need to run an oil cooler. We filled the system with Motul fluid and powered up the pump. A little bit noisy… but hey, it is a race car. After two bottles of fluid and working the steering vigorously from left to right to bleed the system I was happy to see that none of the fittings had leaked. Electrics: The wiring of the pump was easy. There are two sets of wires coming out of the pump. The lighter gauge wires & plug we discarded. I think they are something to do with turning the pump on after engine start up in the stock Toyota MRII configuration? There are two thick wires in one connector - one red and one black. You must remember that the pump draws a lot of current (allow for 60 amps), so you need heavy duty wiring. All the parts are commonly available from most automotive electrical suppliers. We used 8 gauge wires with an 80 amp circuit breaker. We mounted the Circuit Breaker beside the shifter so it is within easy reach of the driver so if he wishes, he can turn it on and off, but for a street car you would probably need to also use a high power relay to switch the Steering pump motor on after the engine is started. I don’t want to get too carried away as my electronics knowledge is very basic… The pump draws 15A with no steering input, and 30-50A when turning the wheel quickly. The Test: It worked pretty well driving around the yard and down the street. The real test would be at the track. So off to California Speedway for the SCCA Cal Club first round of Honda Cup January 27& 28 2007 So apart from telling lots of lies about the racing and how the older I get, the faster I was … All I can say is… Fantastic! It works beautifully, one of the most worthwhile modifications I have ever done! This will be a standard fixture in every one of my Race cars from now on. Pic 1 Pic 2 Pic 3 Pic 4 Pic 5 Modified by KIWI at 4:07 AM 2/14/2008

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[STN_Pat]

very very nice.

thanks a lot for sharing.

[98SpecR]

good write-up kiwi .

[Silchuki14]

Nice mod and thanks for sharing.

I have one questions:

Where did you buy the can that hold the fluids, Pic #2 (If I read correctly)

Thanks

[KIWI]

Originally Posted by Silchuki14

Nice mod and thanks for sharing.
I have one questions:
Where did you buy the can that hold the fluids, Pic #2 (If I read correctly)
Thanks

Yes, sorry I forgot to mention, I bought the Reservoir from McKENZIE OFF ROAD. However similar tanks are now available from most of the aftermarket suppliers, like Summit, or any off road parts store.

Kiwi

[Justin Jones]

Wow, that's sweet.

Currently i have a permanently de-powered DC2 rack in my car. After seeing this thread I'll be on the lookout in the future for another DC2 rack in good condition with the seals intact, and also an MR2 power steering pump. I'd love a setup like this, combined with a steering quickener this would be sweet.

[DB2-R81]

Hello Kiwi,

Any ideas on the capacity of the system for an autocross setting? An average lap on a road course may have 12 to 15 corners in two minutes while a single autocross run may have 35 plus corners or steering inputs in half the time frame with a much higher demand on a power steering system. What sort of reserve might the system support?

Thanks!

[dirty19]

Could this also work on a EG civic with an EX steering rack?

[KIWI]

Originally Posted by DB2-R81

Hello Kiwi,

Any ideas on the capacity of the system for an autocross setting? An average lap on a road course may have 12 to 15 corners in two minutes while a single autocross run may have 35 plus corners or steering inputs in half the time frame with a much higher demand on a power steering system. What sort of reserve might the system support?

Thanks!

If you use a reservoir the same as the one I used, you should have no problems. I have put our car through it's paces many times while testing at Willow, both on the track and on the skid pad in simulated autocross. I have not seen any inconsistency in the way the unit responds even when being thrashed.
I still have not seen a need to fit a cooler either.

Kiwi

[KIWI]

Originally Posted by dirty19

Could this also work on a EG civic with an EX steering rack?

No reason why it cant be used in a EG with an EX Steering rack. You may have to mount it in a different place depending on the space? But theoretically it should work just the same.

Kiwi

[JDM_JNKY]

total costs of this mod.? maybe I missed it?

[get RIGHT]

Great write up. Thanks.

[RagingAngel]

Hey Kiwi, are any of your cars fitted with a steering quickener?

If not, how would it affect the electric steering pump there? Would you feel it necessary to run a cooler then?

Thanks for the detailed post. This is great stuff!

[RedZone]

this pump works great, we used this on Andrie Hartanto's civic all of last season with no problems....

we mounted ours differently but it worked well.

[Airbag Club]

great write up.. i might look into doing this in the near future..

[KIWI]

Originally Posted by RagingAngel

Hey Kiwi, are any of your cars fitted with a steering quickener?

If not, how would it affect the electric steering pump there? Would you feel it necessary to run a cooler then?

Thanks for the detailed post. This is great stuff!

My Crew Chief Brian Slames "Scooby" Has a steering quickener on his little Type R powered EG Hatch, along with all sorts of other goodies we have been experimenting with. There were some Pics of his car in an earlier post on the rear wings we have been experimenting with. Brian's car has the OEM power steering unit but he loves the Steering Quickener. We will probably try the quickener on my #66 K-24 Car soon. With the 300 Hp it should be making I'm sure it will be helpful?

As far as an oil cooler is concerned- I have not seen the need yet, but it is a very simple job to run a small cooler in the PS system.

My next priorety is to build a nice compact Electrical Transmission Oil Pump and cooler. One of the problems that is going to arise even in Club Racing with the popularity of Splitters, Air-dams and undertrays is rising Gear box temperatures. We have recorded Transmission temps of over 300 degrees in the past and that needs to be addressed.

Kiwi

[117]

Very nice work on the electric power steering pump!

On the transmission cooler, do you install fittings on the drain and fill plugs, or do you drill the case for new fittings? If you drill new fittings, how do you determine their locations?

[KIWI]

Originally Posted by 117

Very nice work on the electric power steering pump!

On the transmission cooler, do you install fittings on the drain and fill plugs, or do you drill the case for new fittings? If you drill new fittings, how do you determine their locations?

Thanks, The trans cooler will be the topic of another thread soon. However, the testing I have done so far indicates that using the drain and fill plugs is not the optimum way to go. There will be an article coming out soon where Gear-Speed will be doing a feature on our new GEAR-X Prototype Straight Cut 6 Speed Gearbox. We may include the trans cooler in the article and the track test. Keep watching....

Kiwi

[kommon_sense]

Looks great. Ive been researching doing the same. The only suggestion I would make would be to get a power steering fluid cooler if you don't already have one in the system. You can get an inexpensive trans cooler for about $30 from summitracing. It will prolong the life of the pump. Just wire it up so you have pump -> rack -> cooler -> reservoir -> pump

[rotten]

Originally Posted by KIWI

SPECIAL PROJECTS MOTOR SPORTS
The reason for this swap is twofold: (A) to reduce the Horsepower drag from the engine driven power steering pump. On an engine Dyno the stock DC5 ps pump and rack uses 8.5 hp peak, while in a straight ahead position. On a lower powered B series the loss was 5 hp peak. The power loss from EHPS is between 0.25 and 0.75 hp (via the alternator), depending on steering load.
And

The guys in the rally community have found that the Hydraulic EPS units end up taking more parasitic loss than the factory Honda units.

I was going to go this same route either using the MR2 pump or some of the newer Mazda units, but decided against until I can get some Apples to Apples comparisons.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
(B) The reason I wanted the power steering at all is that after over thirty years of International Touring Car Racing, I have found it is faster around a race track than with manual steering. The lap times of a high powered front wheel drive racecar with a lot of castor, will improve if driver fatigue is reduced. Call it old age if you like, but I prefer to finish an event not feeling like I have just survived the fight of my life.
</TD></TR></TABLE>

This is absolutely true.

[Justin Jones]

I wonder how this pump would work:

http://cgi.ebay.com/ebaymotors...ZWDVW

[rotten]

I've heard that the Subaru pump draws more current than the MR2 pump.

[JDM_JNKY]

Originally Posted by JDM_JNKY

total costs of this mod.? maybe I missed it?

x2

[KIWI]

Originally Posted by Justin Jones

I wonder how this pump would work:

http://cgi.ebay.com/ebaymotors...ZWDVW

I see no reason why it should not work? Looks very similar to the MRII version.
Are you going to bid on it ? If not, I might just to check it out.
The problem I forsee in putting together a complete kit is the availability of good used pumps. Now if the Subaru type works and I believe there is a Mazda electric power steer pump available as well, then it might be a worthwhile proposition.

Kiwi

[KIWI]

Originally Posted by JDM_JNKY

total costs of this mod.? maybe I missed it?

With everything, Pump, Bracket, Pressure lines, Hoses, Hose fittings, wiring, Circuit breaker, Reservoir etc.
My cost was around $375.00

Kiwi