Electric Power steering <Toyota MR2 Pump>

[jjbmwm5]

I'd honestly take a look at the area right next washer bottle it of course must be above the pinion.. I got my mr2 kit minus the steering sensor yesterday. Steering sensor broke when I was trying to remove it so it looks like i'll be calling up toyota. Got the kit for 50 bucks from a junker here in the area, mud in the yard was butt hole deep on a 10 foot Indian and it smelled like gear lube but i can assure you there are 0 epa violations there....

[DSPXR4ti]

I know they maybe more expensive but the 2007-09 Mazda 5 van has an all aluminum EPS unit, looks about the same as the Mr2 one and has a little reservoir just above it. I'll be looking for one of these.

Ben

[DPDISXR4Ti]

I know they maybe more expensive but the 2007-09 Mazda 5 van has an all aluminum EPS unit

Have you checked to see if anyone else has retro-fitted this one Ben? Whenever possible with crazy stuff like this I prefer to walk in someone else's footsteps and leverage their learning curve.

[DSPXR4ti]

I know they maybe more expensive but the 2007-09 Mazda 5 van has an all aluminum EPS unit

Have you checked to see if anyone else has retro-fitted this one Ben? Whenever possible with crazy stuff like this I prefer to walk in someone else's footsteps and leverage their learning curve.

Nope, I just saw one when I was working on it and it looked just like the Mr2 one, I going to go get one after Xmas, and see if it's lighter for one and 2 it's doable, I've seen alot more Mazda 5's in the bone yard then the Mr2.

Ben

[jjbmwm5]

I was trying to get an Opel/vauxhall Cost is just crazy. Just remember you have to adapt the hoses to fit your rack and pinion and rack and pinions are very fragile at that location be careful trying to force something in. I believe your are looking at 14mm and 16mm ports (just like mustangs). May just be easier to get banjos that convert them to AN fittings and get some an lines made. That can be costly though another option is always a company called GOTTA SHOW we use them A lot when we don't have a fitting for a customers ride. Ill have my garage back in February so I'll know more then my rack is here at our shop getting powder coated and rebuilt as we speak kinda cant wait to put it in the car.

[DSPXR4ti]

May just be easier to get banjos that convert them to AN fittings and get some an lines made. .

There is a company here in San Jose that will make any PSI line I want. So that not the problem.

Ben

[DPDISXR4Ti]

Just bumping this thread with a link showing how someone retrofitted the MR2 stuff to a RX7. The later Mazdas such as the RX8 and Mazda5 van that Ben mentioned above were ruled out as donors as the electric power steering on those is tied in too tightly with the overall car/engine management.

http://www.rx7club.com/fabrication-250/ ... on-847818/

[thesameguy]

Been working on this for my Saab - the Mazda pump is not a good fit for transplant. However, there is the Saturn/Opel Astra pump, which is five bills reman'd from rockauto these days. The MR2 pump is a nice choice because of the ease of integration, but used ones typically get $300 on ebay, probably due to scarcity. The MR2/MRS Spyder pump is also a choice.

One thing to remember about EHPS is that a full lock they will suck 65-70a, which would just about kill an XR. You'll need to get at least a 95a alternator in to support these pumps.

But, in '16 you can also skip EHPS and go straight to electric. The system in newer, small GM cars as well as the 2nd gen Prius & Yaris is transplantable and almost entirely self contained. I know there isn't room for this in the Saab, but there might be room in the XR. Maybe.

[thesameguy]

Forgot - there is also the Mini Cooper pump. About $300 from rockauto. It has a high failure rate, but a) that could be a result of the factory placement (gets hot), and b) it does result in a lot of reman availability. IIRC the Mini pump gets VSS from CAN, but like the Astra pump does have a default assist mode so you don't *need* the speed input.

What someone *really* needs to invent is a doodad that aggregates discrete sensor outputs into a CAN signal, so us old car people can use new fangled whizbang computer parts.

[Choochoochoo]

So say you do this swap, you gain power from ditching the belt driven pump, but how much do you lose due to the alternator being worked harder? Does it equal out? Is it less, more? Don't get me wrong, I LOVE the idea of ditching the belt driven pump, the thing wines like crazy and I don't like it. But, is the swap worth it? Probably, unless it causes problems with the alternator...

[thesameguy]

The problem with a mechanical pump is that it has to provide the *most* boost at the lowest speed so they waste a lot of power once engine speed increases. A good pump might be sucking 5hp to do nothing. A bad one might be 10hp.

At full tilt the EHPS pumps use about 70a, which takes roughly 1.3hp to generate via your alternator. That 1.3hp loss happens when you're at 5mph in a parking lot with the wheel turned hard over. On the freeway, they use about 7a, which takes roughly .13hp. Unlike a power steering pump which wastes more power the faster it goes, power that you want to have available the faster you go, an electric pump uses less power the faster you go, making that power available to you.

Is winning back, say, 5-6hp worth building a $600 EHPS system? I mean, you could just bump up the boost .1psi. So, no. Probably not. But my application for EHPS is getting rid of an old, noisy pump and hopefully earning adjustable power assist - I hate how overboosted both my Saab and the XR4Ti are. I am sure I could lower boost by messing with the relief valve in the pump, but EHPS is way more fun.

[Choochoochoo]

The possibility of lowering the position of the pump is kinda nice too...

[DAReese]

So, we keep the leaky pump and hoses and add an electric motor and some gadgetry, to save... what, in terms of hp?

Probably 2 or 3 HP, and the "added weight" is where these cars needed it, never mind
that the pump is constant pressure, no belt to throw/break. KISS principle at work...

My first car was a 76 Capri II. Replacing the rubber bushings with plastic made it ride like a go-kart. I browsed many a Dobi catalog back then.

[thesameguy]

I also forgot about the MkI TRW pump that's on a bunch of cars, probably most accessible on the 2nd gen Volvo S40/V50. This pump is CAN capable, but in its default limp-home mode is load-responsive. Essentially it attempts to run at a fixed rpm, generating fixed pressure so as you load it up by turning the wheel it responds. When it has vehicle data like road speed and steering angle it can be proactive, but without that data is has to be reactive. I like this pump because it's new(er) and common, but I am concerned about lag when worked heavily. Once it's spinning up it's probably okay, so like a chicane likely wouldn't pose a problem, but an unexpected hard steering correction might result in unpredictable assist. I still like the pump though and am inclined to try it.

My understanding is that the MkII version of this pump requires a CAN signal or it's not so useful.

[DPDISXR4Ti]

I also forgot about the MkI TRW pump that's on a bunch of cars, probably most accessible on the 2nd gen Volvo S40/V50.

Here's a good thread on fitting the Volvo pump into a Mustang...
https://www.corral.net/threads/volvo-el ... p.2499503/