Electric Power steering option

[ttsupra2503]

So I was looking online at an electric power steering system and came across something very interesting that might be able to be done with the help of an importer. I will post the following article to see if someone else can help with the fitting and use of the system. I am looking to see if the pump is available new locally but without further delay. here we go

I have done a fair amount of research on the internet regarding converting various vehicle's hydraulically assisted rack and pinion steering from a belt driven pump to an electric motor driven pump. Some conversions were to achieve space near the front of the engine for a supercharger. Others were to reduce engine loss for drag racing. Some were to improve the performance and handling for circle track or road coarse racing. Most were for gas to electric powered vehicle conversions.

There are two types of electric motor power steering assist. One type is an electric motor with shaft and gearing integrated into the steering column that assists the driver in turning the steering shaft. This is the latest technology because it saves power and reduces fuel consumption. Unfortunately, when the system fails the vehicle is nearly impossible to drive. It would also be impractical to retrofit to my Explorer.

The other type replaces the belt driven pump that pressurizes power steering fluid to the steering rack with an integrated electric motor driven pump to perform the same function. This configuration is much easier to retrofit and consequently used electro-hydraulic pumps are in high demand. The only electro-hydraulic pump I found suitable for retrofit on my Sport was used on the early 1991 thru 1995 Toyota MR2 - a mid engine sports car hence no belt driven pump. This particular series has no integrated power steering reservoir allowing it to be short enough (hopefully) to fit under the battery tray. I have seen these used units sold on eBay for $400 and new ones cost over $800. Last night one was advertised with a purchase now price of $90 and I bought it with no hesitation.


I have an electronic copy of the 1991 MR2 wiring diagram which shows several other power steering related electrical components: ECU, relay, power driver module. These are also expensive to purchase and difficult to find. However, the pump will run at full speed continuously with just power applied to 2 pins. The other components reduce the power consumption (up to 80 amps at startup under load) and vary the pump rotation speed for more assist at slow vehicle speeds and less assist at fast vehicle speeds. Many of the later generations have a steering angle sensor (SAS) that increases pump speed when the steering wheel is turned faster. My Tahoe had variable assist power steering with an SAS on the steering column. As it aged the sliding contact surface became coated making the contact unreliable. On occassion when the wheel was turned at 30 mph the power assist would go to full eliminating all steering wheel turning resistance. If I was not quick to respond the vehicle would unsafely oversteer. After I figured out what was going on I periodically cleaned the contacts by spraying with electrical contact cleaner.

This brought to mind putting the power steering pump into the supra and moving the alternator to that side of the 7m motor to allow for a front facing intake manifold. Even just getting rid of the pump off the motor and into something a little better to control would be a bonus for the average owner. I am a while before I can pursue this venture but if anyone else can look into this please use this thread to post status and pictures.

 

[hvyman]

You can buy a drop down brackets for the alt...

Be a log cheaper than going through the hassle and money for electric power steering. Some of those units use 24v as well and it could add weight to the car.

Personally I love the feel of pps on the mk3.

 

[Poodles]

IIRC, those MR2 pumps are notoriously unreliable and expensive...

 

[ttsupra2503]

This is why I ask though. I figured for the money it would be an option. I see a fair bit of negativity towards those pumps.

I found rebuilt pumps on Rockauto for under 100 dollars. Thats why I figured it would be an option. Find a way to put a pressure switch in the system so when pressure is applied to the rack it would increase the power to the motor. Make it adjustable so you can tweak it from inside the car and Bobs my uncle... no... he really is. lol

The way I would really like to go is electric steering to eliminate the fluids in the system altogether.
Direct electric motor help. If I could install a manual rack from.... lets say a 1988 Monte Carlo which is 2 to 2 1/2 turns lock to lock for 120 bucks. Install a factory column assist motor from one of the European market cars (seems like over half of them over there have electric steering including the rav4) and apply a torque sensor onto the steering shaft to play the roll of assist control. Under 2k (if I was diligent with the motor system) and something that is adaptable and tough. If you want sport steering you just turn off the motor.

I also see a lot of the newer electric steering systems out there (5-14 thousand dollars lol... yeah right) that eliminate the hydraulic system all together. Most of those are out of the price bracket I am thinking of but it is an option.

btw... has anyone looked to see how the rav4 controls the power steering rack? And it is a great upgrade to our old cars to help get our steering wheels lighter and our "track" times quicker.

 

[ttsupra2503]

And I see another minor option due to its accessibility from the rock store. I am thinking that a 2009-2012 matrix rack might be an option (should be available from a wrecking yard as well) will check on prices tomorrow.

I know its easier to leave the original system in the car but I would like to be one of the first to find a electric system for our cars.

btw.. the bracket to move the alternator down is an option and fairly easy to boot. Its not the main reason why I want to switch from a belt driven power steering pump. I just want to get stuff out of the engine bay to make it cleaner.

 

[ttsupra2503]

Has anyone even cared to get rid of the power steering in their car? lol... I feel like i am the only one here

New thing on the table... 2009 to 2012 matrix electric power steering rack. Thoughts and idea's people

 

[Poodles]

The electro/hydraulic systems are fine and when properly setup feel just like a normal system.

The direct electric setups that they're using now are being ripped apart by reviewers and are said to ruin the feel of the car (porsche comes to mind, and Top Gear wasn't the onlt one to complain)

 

[te72]

Has anyone even cared to get rid of the power steering in their car? lol... I feel like i am the only one here

New thing on the table... 2009 to 2012 matrix electric power steering rack. Thoughts and idea's people

Nope, nobody has ever removed the power steering setup on a Supra before. :sarcasm:

I kid, of course. I ran my 88 without for a good while, actually preferred it most of the time, gave a very direct feel. Something that, if you read much into electric only powered steering, you'll find that the technology isn't quite there yet. Not to say it won't be in 10 years, but for the time being, I wouldn't change mine out personally.

However, if you wanna pioneer, at least do us the favor of documenting it, pictures, words, wiring layouts, etc... New ideas don't always pan out, but sometimes they do.

 

[Poodles]

Nobody has correctly depowered a supra rack though

 

[ttsupra2503]

I will definitely document it fully with pictures and what I had to do to make it work properly. I have been thinking and I think I am going to use the electronics from a MR2 to control an assist motor on the steering column running to a manual rack.

That way if the steering fails while driving I really should only notice a minor change until lower speed.

I am in the midst of finding a local importer again that will help me with getting the mr2 parts in full. I will have to adapt it to the supra steering column but I should be able to do it since that parts are all Toyota.

 

[Prism11]

Just to give you another option, you could look into using an electric power steering rack out of an rx8.

I have an rx8 for a dd and feel like it gives a good feedback feel to what is actually happening down at the wheels.

EDIT: A similar discussion is on the rx7club forums, it might give some insight or other options. I'm very interested in seeing this done.

http://www.rx7club.com/3rd-generati...ectronic-power-steering-conversion-fd-991025/

 

[LordDigital]

Nobody has correctly depowered a supra rack though

Wrong - Toyota Did IIRC there are two types of dePowered racks that were available back in the days 15.5:1 and 16.5:1 ,the powered rack was 14.5:1. Many TTA and Private N/A Race Supras from the GroupA era used them and at least one that was later converted to turbo for hill climbs still have rack like this. TRD cars were always with Type A rack (14.5) due to their extreme minimum weights and super high castor settings.

 

[IJ.]

Let me see here... you want to take an already failure prone steering technology from a Mid Engine light car that uses small tires and put it in a Heavily weighted front engine car with large tires ... all so you can "clean up the engine bay" nah can't see a problem there.. :nono:

 

[ttsupra2503]

Are you talking about the MR2 electric pump IJ?

The stuff I want to pull from the MR2 is toyota compatible steering and speed sensors. When I get this "Failure prone technology" and can look at what is prone to failure and maybe why it might fail I can replace or fix the issue.

I would love to see what type of manual racks I have the option of. I know the chevy rack is super cheap but really strong and used to make late 60's and earlier manual steering cars handle like a dream. I was gonna try using that rack first by itself with the stock steering column. That way there is nothing to fail. If that still feels stiff then I would add the MR2 sensors and relays (might replace some if needed) and run an electric assist steering system with the same rack.

IJ.... what goes wrong the most with the MR2 system? Do you know of any places that offer replacement/fixed units for a little more money then stock stuff? Do you like smart people that refuse to quit?

 

[Poodles]

Wrong - Toyota Did IIRC there are two types of dePowered racks that were available back in the days 15.5:1 and 16.5:1 ,the powered rack was 14.5:1. Many TTA and Private N/A Race Supras from the GroupA era used them and at least one that was later converted to turbo for hill climbs still have rack like this. TRD cars were always with Type A rack (14.5) due to their extreme minimum weights and super high castor settings.

Last I knew they ran power steering still (since many of their DNF's was from failure of the system)

...and I really meant in the realm of the forums

 

[LordDigital]

Last I knew they ran power steering still (since many of their DNF's was from failure of the system)

...and I really meant in the realm of the forums

Don't really remember too many power steering failures ,or these were hard to spot around the piston holes and BHG issues that the factory race MA70 had until their last race at SPA in 1990

It is also true that on this forums John Smith did mention that his race supra had a lot of failures due to high pressure hose bursting when it came from Japan ,so he had to dial back the Castor from 11degress to under 10 and then he was pretty reliable. Not sure what high pressure hoses were used back in the days ,but I raced mine with 11castor on fully shut progressive valve and won the local unlimited class championship with no failures

 

[IJ.]

Bunch of DNF's here due to steering failures when they raced in Group A..

 

[LordDigital]

Bunch of DNF's here due to steering failures when they raced in Group A..

Ian ,are you talking about ATCC or JGTC championships?

 

[IJ.]

Aussie races

 

[LordDigital]

Aussie races

I see I was never able to find too much info related to the Ma70 Group A program in Australia - from the little that I know... after TRD realized that they can't beat the laws of physics and ever be competitive with the evolution Supra in JGTC they send 2 or 3 race cars to AUS ,factory support was limited to parts and funds but no engineering ,setups ,etc - this could've been the reason why the AUS teams got all these power steering issues ,that again according to John Smith were sorted out after they changed the caster.

I really do not remember a single power steering failure in the JGTC statics of the Ma70 Supras ,Frank's site is not available to double check and jaf.jp does not list reasons for retirements but roughly out of 45 total grids for the 3 factory supported teams ,they got around 15 retirements mostly due to BHG ,pistons and clutch issues.