Please do your usual great job of documentation, Day.  I'm very interested in this...maybe.

The stiffness could be the result of an electrical issue.  These EAPS systems typically vary the amount of assist based on road speed.  More assist at slow speeds, less at high speeds.  My guess is the system defaults to the lowest amount of assist if its not seeing a speed input or communicating with the car's ECU.  Its just a guess, but given how integrated the electronics are in new cars its a pretty decent one. 

Return to center is in part a product of caster.  A modern steering system is designed to have 4-6 degrees of positive caster.  Without it they typically don't return to center very well. 

Does it require a particular VSS signal or would it be happy with the signal from a late 80's Ford VSS?  I don't know the pulse rate, just that they work well with the aftermarket cruise controls that I have installed.

zakdaddy99 wrote:

I am finishing up my project doing the same thing to my 66 Mustang. I am using  a 2010 Corolla column from a pick-n-pull. Mine works but the steering is stiff and has hardly no return to center. I have a factory power steering car. Still has the original box. Replaced all of the linkage with manual steer parts. Fun project but I am trying to solve the stiff steering. 

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I have seen that exact complaint from others in my research. The issue is the steering box. The solution is to go R&P or use a EPAS you can use an aftermarket module  with so you can turn up the assist.

Bullet Bob wrote:

Does it require a particular VSS signal or would it be happy with the signal from a late 80's Ford VSS?  I don't know the pulse rate, just that they work well with the aftermarket cruise controls that I have installed.

I honestly don’t know but all the research I did only showed these hooked up two ways. 1 in fail safe mode with no aftermarket module or 2 with a speed module that uses a potentiometer to set your speed . The guy on eBay who sells the modules probably knows but don’t know if he would share that information or not. I do know this, if it won’t take your VSS signal and  because a potentiometer is used to adjust the fake VSS signal on the aftermarket module a second  module could be made that translates speed into a specific resistance and then wired in place of the pot. in other words giving the correct speed info to the EPAS. . I am enough of an electronics hobbiest to know it can be done but not good enough to know how.
 

Anyone serious about doing this mod should read the 67 page post on VMF  Best $200 mod ever(epas)
It’s a long read but I has tons of info from many different installations.
The Prius unit operates in a fail safe mode at a fixed rate, the Vue unit that I used needs a “Bruno box” about 50 bucks on line. The Vue with the Bruno box has a variable rate control that can change the “boost” on the fly. The Vue unit set at maximum will give one finger parallel parking and when turned all the way down is like manual steering, perfect for the freeway. The Vue EPAS is not fixed, most other makes are.
Maximum caster will not get RTC to original or new car specs, on my set up the last half to three quarters turn needs to be done by the driver. The issue is the type of gearing in the unit. RTC is a common complaint on all the threads I have read, it is the nature of the beast.
A couple of places offer ready made EPAS units but I don’t think any are plug and play, needing a lot of machining and fabrication, plus they are very expensive.

That link was quite a slog to read through.  Ilike this one a little better as it doesn't use the eBay module 

MS wrote:

My experience with racks having the third section have all been bad. The ONLY WAY to make that third section of steering shaft work properly is to mount the center shaft solidly between two bearings, one at each end, so the center shaft is held in one position and it cannot slide up or down, and all it can do is freely rotated on the bearings. Note I said BEARINGS, not spherical rod ends, which are NOT bearings in any stretch of imagination. This requires four ujoints to complete the system. Any other way and it will just bind up and not steer smoothly.

That has not been my experience at all.  When I retrofit the GM J-car rack to the Galaxie I did a suported intermediat shaft with heim joint.  Once I eliminated all the flex in the suport there was no issue with binding.  Put lots of miles on it without issue and it steers as smooth as it did the day I installed it.  When I built it, it had to pass the "Day Scovel manual not moving test" where I rotated the steering wheel lock to lock with the car sitting on the ground engine off car not moving.  I knew that would be the max stress the system would see and once it pased that test I was good to go.

 

TKOPerformance wrote:

Personally I wouldn't be happy unless I had the variable effort for the steering working properly. 

I have spent a lot of time researching this and there are a lot of people that have a similar opinion to yours and it is very amusing to me.  I understand and respect striving for perfection but to dismiss something that works well because it doesn't live up to its full potential seams a little drastic. The main reason I find statements like yours amusing is hydraulic power steering systems do not very the assist level based on vehicle speed so why must an electric assist very with speed? 😁 

It would totally make sense for safety's sake if this was uncharted waters (default to the OEM design to avoid unforeseen issues) but tons of people have been doing this mod since 2014 and have had fantastic results.  There are even overpriced aftermarket kits for our cars to do this upgrade and they are using the same module that is being sold on eBay that does not control assist based on speed.

To some degree an electric power assist will very its assist level based on vehicle speed because of the column torque sensor.  The more resistance coming from the steering the more effort the assist motor applies so at lower speeds especially when parking the EPAS will be applying more power, and in that particular case it will be superior over hydraulic as at low RPM some hydraulic power steering systems don't apply full assist.

I am not saying EPAS is the newest greatest thing and everyone who already has hydraulic power steering should replace it with electric.  That would be a lot of time, money, effort for not a lot of improvement.  That is why I am not putting this unit in my Galaxie because it has a good hydraulic steering system, but in my Mustang where I already have a manual rack adding the power assist is an improvement,  It's not expensive, has proven to work well and is a fun project because I can.

As to your thoughts on making it work, If you take the time to read through the thread  Best $200 mod ever(epas) the guy that started the thread developed a controller that did vary the effort based on speed but he couldn’t get liability insurance to be able to put it into production.

I still think a DIY "fix" could be made to work in conjunction with the eBay modules because the module is controlled by a potentiometer. It would not be that hard to use the VSS signal to drive a digital potentiometer  that would replace the knob style potentiometer.

It would require a little more electronics knowledge than I have to use the VSS to drive the digital pot but the end result would be variable assist based on vehicle speed.  I am sure there would be a lot calibration required to get it dialed in, but I digress.

For me I’m trying to keep things as simple as possible.  The more complicated you make it striving for all the features the more parts you must add that can now fail and for that very reason I’m not running an EPAS that requires a module at all.  When I first saw the EPAS I was interested but only slightly because of the aftermarket module but once I found I could use a Toyota unit in fail safe mode I dove in head first.  The Toyota EPAS should give me a constant assist at a reasonable effort level no module required.
 

TKOPerformance wrote:

There are hydraulic assist steering systems that vary assist based on speed.  Smokey Yunick designed the first such system in the '60s.  Plenty of OEM systems have used it.  I've just not seen one offered for a classic Mustang, though I'm sure someone has built one. 

This I knew as there are some modern cars that the PS pump is wired to the ECU.  I had just never seen anything like that on a classic and that was the amusing part.  As I was reading through the long thread on the VMF lots of guys were saying something similar to "it won't be good if it doesn't vary with speed"  and thats why I had to laugh because they are driving classic cars with old school power steering or manual steering.

TKOPerformance wrote:

Also note I didn't say I wouldn't use it; I said I wouldn't be happy.  I use things I'm not happy with all the time. 

That makes a ton more sense. 😂 I thought you were totally against the mod because of the lack of variable speed.

I hope your friend comes through for you.  The guy on VMF was able to do it, he said it was fairly simple and used VSS and an RPM signal.  It is however above my pay grade.

 

Nos681 wrote:

Any particular reason for this model Daze?

 
Sorry I missed this. I went with the Toyota epas because no additional controllers were required. It was designed from the factory to go into a default mode if it looses signal with the ecu

Outstanding work Rudi.

josh-kebob wrote:

Rudi and Day,

Could you please provide info on exactly how to post pics? You've obviously cracked the code. Are you posting from a computer or smart phone? The forum users would appreciate knowing. Thanks.

 
I have a subscription to imageshack. I can upload images from my phone or computer and then I cut and paste the image address into the post using the image button.