Electric Hydro Mr2 Power Steering

[TougeLabs]

I was ust going over this idea with brewster240 about doing a electric power steering setup in my car. Was wondering if anyone is running one

Heres the perks

Pump wont rob any power
can run it with stock alternator
speed sensitive power steering
and really cool

[racepar1]

The dent sport garage s-13 has that set up. They mounted it on the passenger's side where the kick panel used to be. Sorry, but nothing new or groundbreaking here.

[!Zar!]

It's been done.

More commonly with Renault electric ps pumps.

Search the FC forums. It's pretty common over there.

[TougeLabs]

o racepar1 i know this is not new i was not trying to come across like i had an original idea...I was just looking for some insight on the project, I have been trying to source a hydro but had zero luck.
From what ive been reading the mr2 one has a flow sensor that adjusts to how hard it is to turn the wheel at diff speeds kinda interesting. I went with a meziere elec water pump so i figured i would go this route as well.
thanks though guys ill keep you updated...

[projectdrifter]

i had looked into a similar setup.. maybe dent sports can chime in.

[HyperTek]

hmm i never looked into that stuff..

tons of first gen mr2 at my local yards, i presume they have it too?

[DJ_Sunrise]

I work parts at a Toyota dealership. Let me know if you need anything. part numbers, parts, compatibility, etc etc

-Bart

[TougeLabs]

Ok i picked one up hopefully its what i was looking for going to the yard to pick it up monday.
Anyway I will take piks and everything this system is going to be awesome cant wait to start on the project after my cage is done

[CAPoweredS14]

I'm also very interested in this as my PS pump seems to be going out on my CA and would like something new. I also like the idea of it freeing up load from the crank. I don't mind making more SS lines! Keep us/me posted man.

[TougeLabs]

No problem man.

[GSXRJJordan]

Sorry to bump this old thread, but I've been looking into this very seriously, as I'd love to stuff it under my front fender on the drivers side behind a cooler since the MR2 pump is so light (and keep my engine bay super clean, no wires/reservoirs, etc).

Pumps:
There are a lot of hydro-electric pumps - older Euro cars have them, and the Subaru SVX had one - but the 2nd gen MR2 pump is the smallest/lightest/most reliable. They can be sourced from $50-$100 apparently, although I have yet to purchase one.

Lines:
Same as a regular power steering pump - high pressure from the pump to the rack, low pressure from the rack to a cooler (cause, why not?), low pressure from the cooler back to a reservoir (which just has to be higher than the pump, so you could still stuff it low in the car), and of course low pressure from the reservoir to the pump. Regular SS braided line is not the best idea for the high pressure line, because of the ridiculous pressures generated (up to 2000psi), but there's tons of high-pressure lines (some rubber and some rubber/SS) you can use. High pressure fittings must also be used, duh.

Power:
This is where I got surprised - the MR2 pump pulls between 70A and 90A at full power - that's more than your alternator can generate! This means the battery's being used as a buffer, but still, that's a lot of juice, especially if you have a sound system also. Most people run either a 80a-100a self-resetting circuit breaker or just a fuse, and >8ga wire.

Control:
This is where it gets tricky. The MR2 used a bunch of sensors that interfaced with a power steering control box vary the input voltage to the pump, less voltage = less pressure generated. These include steering angle (pump generates max pressure at full lock, so if you keep your wheel at full lock for a while you'll burn out the motor - the stock control unit keeps an eye out for this - also gives you more pressure when you turn the wheel faster), vehicle speed, and something else.

A full listing/tutorial for installing the OE system can be found here.
Toyota MR2 Power Steering System

Another interesting find was some guys using the MR2 pump with their own control stuff - can't find the full writeup, but this is their page:
Selecting a Power Steering System

I'm concerned with a couple things - first, that it's going to be a bitch to find all of the required electrical components to get the Toyota OE setup to work right. Second, that if I hook it up at full power that it's going to be overcorrected and draw far too much current to be efficient. Most people that use them at full power all the time are racers, and I don't think I want to make that huge of a trade-off because my car sees street driving 99% of the time.

I was hoping any others (Luke asked Bill @ DentSport to chime in, he's the only other person I know of) that have experience with the system can tell me about the control aspect.

[Bigsyke]

Good work man, looks like it would be a pretty easy install once your source the lines/fittings and pump.

The biggest and most important would be controlling the ammount of power it uses. If you have disected a PS pump the inner fins are so small and the draw isnt as large as the alternator would draw.

[GSXRJJordan]

My first thought was a simple potentiometer - you could reduce the voltage going to the pump from 13.5V all the way to 0V, but not if the motor's drawing 70 fucking amps! You'd need a PWM controller connected to a relay, but relays that switch fast enough to keep up with a PWM controller and also can handle 70A DC are expensive.

I'll probably find a PWM controller and wire in a knob (for max voltage, so I can fine tune how much pressure is sent at max) and a steering column sensor (so when you're not steering the pumps not on), and see if I fry a starter relay.

[soreballz]

^Upgrade to a Quest alternator. =]

[GSXRJJordan]

Haha I'd wire in a couple capacitors to help out with the quick on/off DC loading before I upgraded the alt... it'd be easier on the whole electrical system.

[jandysil80]

another alternative to the quest alternator swap is to have your stock one upgraded. I recently had my stock SR alternator rebuilt to 150 amps, big upgrade over stock 80 amps. Check out Maniac Electric Motors.com High Output Alternators | Fan Motor Assembly | Power Cable Kits

[GSXRJJordan]

You guys are totally missing it - I'm not worried about my alternator, I'm worried about the pump always being on (which is not just bad for the electrical system, it makes the steering unnecessarily light).

[Bigsyke]

Originally Posted by GSXRJJordan

You guys are totally missing it - I'm not worried about my alternator, I'm worried about the pump always being on (which is not just bad for the electrical system, it makes the steering unnecessarily light).

Speed activated cutoff switch.

[GSXRJJordan]

Originally Posted by Bigsyke

Speed activated cutoff switch.

Much easier said than done. Also, doesn't fix the problem of too much pressure the rest of the time. I don't remember for sure, but I don't think the Nissan VSS sends enough voltage to let me tap that and accurately gauge speed (I think it's somwhere less than 2V AC or some crazy shit, I dont remember)... I guess I can hook up the DMM and see what the voltage is across the two wires.

[Bigsyke]

Too much pressure is no problem, most racks have a plastic dampener controlled by a spring. IMO its more the drag off the alternator and FSM states low Bat voltage will affect engine operation.

[S14DB]

Is there any write ups on what PSI and GPM the MR2 pump does at different voltages?

What is the GPM/PSI output of the stock pump at different RPM?

Once you figure this out you can hook up a tach pulse to voltage converter to a motor controller to increase the pump voltage as the rpm increases.

A custom speed and steering angle setup seems like way to much engineering for a simple system.

[dirtdiggler666]

bill for sure needs to chime in on this one i would love to do this someday

keep this going guys lets figure it out

[GSXRJJordan]

Originally Posted by S14DB

Is there any write ups on what PSI and GPM the MR2 pump does at different voltages?

What is the GPM/PSI output of the stock pump at different RPM?

Once you figure this out you can hook up a tach pulse to voltage converter to a motor controller to increase the pump voltage as the rpm increases.

A custom speed and steering angle setup seems like way to much engineering for a simple system.

I'm still searching for a diagram/chart showing PSI (they don't ever show flow, because it's minimal in a power steering system apparently) over Input Voltage - I'm actually not sure that the pump is regulated by input voltage, but that's what the Cameron Software writeup said.

The stock power steering pump is a horrible system to emulate, because you don't want more pressure at more RPMs, you want more pressure when you need to turn the wheel fast or lock to lock. A PWM controller is actually extremely simple, as long as it's hooked up to a relay that can switch fast enough, and like I said, fast switching relays that can handle 70a are expensive.

As far as steering angle setup, the Cameron Software site has a blurb from another guy (Jon "Sheer" Pullen) who made a PWM controller, and uses an optical pickup attached to the steering shaft - this is his solution to turning the pump off while you're not turning.

[turtl631]

Shit, I'd probably kill my battery (PC680) just trying to get out of the ridiculously tight parking spots on my block. 70-90A?! Altima fans draw like 30A at startup IIRC and you definitely notice when they come on. I can't imagine drawing 2-3 times as much current for a longer period.

[bbejj123]

thats actually what this company i was working for was using on there electric trucks. it worked decently well and if u have the funds it wouldbe a fun upgrade. It didnt have any problems with battery and itwasnt even using an alternator so im sure if u have a working alternator it wouldntbe a problem

[Bigsyke]

The OEM pump is at some unreal PSI, I would assume a looped 10psi is enough to assist in steering and preventing damage to the U joints.

[fueled by hate]

Didn't the twin turbo z32 have an electric p/s setup as well?

[GSXRJJordan]

Originally Posted by bbejj123

thats actually what this company i was working for was using on there electric trucks. it worked decently well and if u have the funds it wouldbe a fun upgrade. It didnt have any problems with battery and itwasnt even using an alternator so im sure if u have a working alternator it wouldntbe a problem

Fer realz, they use Electro-hydraulic power assisted steering on lots of big shit. Tractors, back hoes, etc.

Originally Posted by Bigsyke

The OEM pump is at some unreal PSI, I would assume a looped 10psi is enough to assist in steering and preventing damage to the U joints.

Haha 10psi? The lowest I've ever heard of is 1200psi. I would totally like to put a controller on there to see what pressure actually feels good and helps out though.

Originally Posted by fueled by hate

Didn't the twin turbo z32 have an electric p/s setup as well?

Electric power steering is different than hydro-electric - the NSX and S2000 have electric power steering, where the electric motor is wrapped around the rack itself - crazy $$$. Hydro-electric uses an electric motor with hydraulic pressure to actually move the rack. I'm guessing that's what you mean, and no, all VG30s have standard power steering.

Originally Posted by turtl631

Shit, I'd probably kill my battery (PC680) just trying to get out of the ridiculously tight parking spots on my block. 70-90A?! Altima fans draw like 30A at startup IIRC and you definitely notice when they come on. I can't imagine drawing 2-3 times as much current for a longer period.

Srsly. That's why I'd throw a couple capacitors in the system too, just to make sure there's not too much loading too fast. I did the math, and with 70A you'd actually 33 Farads of capacitance to fully offset the momentary drain - ouch!

[blu808]

screw it im gonna make the non power racks I have been talking about.

No cooler
No pump
No lines
No leaks
More power
More room

[GSXRJJordan]

Dude, I'm totally all ears. We'll have to see how they do with lock-to-lock transitions at speed (eg, drifting), but if you can initiate with one hand and lock-to-lock it in decent time, they'll sell for sure.