EPAS conversion

[ether947]

Originally Posted by T-37

King Pin Inclination along with caster will help with return to center. There's a great motoiq article that covers it in detail.

https://motoiq.com/the-ultimate-hand...n-and-scrub/3/

Thanks for the link. I've read that article before but I lost the link to it.

My long-term plan is to get Ground Control Caster/Camber plates so I can dial in the suspension as much as possible, however, I need coilovers first. I am currently on STi struts with RCE yellows.

I've been playing with the preload adjustment on the rack (what a pita to do on the car) and if I used the recommended torque settings (which is like 4 ft-lbs) the steering is way heavier and sticks even more. Too little preload and the rack knocks, but seems to return to center easier. I'll keep playing with the settings to see if I can get better results.

Link to steering preload...
https://bobistheoilguy.com/forums/th...ad-work.43677/

* Registered users of the site do not see these ads.

[ether947]

So, I did the diode mod by buying a pretty expensive mini fuse from Australia to bump my voltage up to 14.6 (from 14.2). It seems to have worked. I haven't noticed any drops in power assist, at least not yet.

Link to the thread about the diode mod.
https://forums.nasioc.com/forums/sho...1602651&page=7

Links to the fuse.
https://www.hkbelect.com/product/235...mpatible-2012/
https://www.ebay.com/itm/322650712885

[ether947]

Update.

I've been going in to work on Fridays and every time I go to reverse into my parking spot the assist drops off a cliff. It's weird because that's the only place it consistently drops off. So, I ordered a BRZ EPAS adjustable controller from the guy in Portugal. It arrived in like two days, which is pretty awesome.

I just installed it and it definitely increased the level of assist. I can turn these 265 summers with one finger on the max setting. I am currently running it on the middle setting.

On the test drive, I noticed that the steering will return to center now which is a welcome change. I think I need to beef up my motor mount bracket now that it producing a decent level of assist. I can see the motor flexing a bit when I turn the wheel.

I think I might have some binding in the steering linkage going on too so I need to investigate that as well.

[Homemade WRX]

Thanks for the follow up! This is definitely a project of interest to me.

[ether947]

Update.

I was having serious issues with the EPAS dying on me and going into full manual mode. This was somewhat manageable with the 5MT, but with the 6MT (swapped at the end of 2021) the steering is ridiculously heavy in zero assist mode. Sometimes, restarting the car will fix it, but even that stopped working. I plan to wire in a switch to manually reset the controller at some point.

After some investigation, I found a pinched control signal wire that was grounding out. I don't remember when, but I relocated the control module underneath the driver's seat. I extended the harness and bolted the module to a piece of plywood for proof of concept and kind of forgot about it as it worked well enough. I think some of the wiring harness was sticking out past the seat and got pinched by a 12-pack or something after a grocery store run. Whenever I hit a big bump, the signal wire would ground out and the module eventually shut down, I assume, to protect itself.

I eventually found the wire and fixed it, but I also bought a newer control module just in case. FYI, some of the older ones have issues shutting down. I would look for modules from 2017 and up. The new module came with a mounting bracket that I modified to mount under the seat (pardon the self tappers). Part of me wonders if the control module has an internal ground that uses the bracket to ground out to the chassis. I haven't driven the car a ton since, but most of my inconsistency issues seem to be gone. I have immediate power steering on cold starts now. There was a delay before. I am a little bit surprised but so far, it is working better than ever.

Anyhoo, here is my current setup under the driver's seat. I had some old ABS wiring laying around that I used to extend the smaller gauge wires.



I am going to redo the harnesses. I am sourcing wiring and connectors now. I want to make this harness modular so I can pull the motor out without needing to pull the entire harness out as well.

[sorrowfulkiller]

Originally Posted by ether947

A quick update.

A couple of weeks ago I took it through the Dragon for a trip to NC. The steering was a little on the heavy side but nothing unmanageable. I also have 265 summers over 245 all-seasons and a 13:1 rack over a 16.5:1 rack now. It cut out on me a couple of times but I haven't figured out the pattern yet. For most of my 2-3hr drive through the mountains, it was fine.

Other than those issues, the system works great. I hear the click of the control module when I turn the key on that reminds me that it is still there.

Recently, as in yesterday, I retorqued my suspension rotating points (top hats, ball joints, etc) and the steering is considerably lighter. I guess I did a good ole gutentight method before. My car has long had an issue where the steering did not want to return to center. I have replaced every steering component on this car and I was disappointed to still have the issue. It returns to center easier but I still have to help it. I'm not sure what the issue is there.

I started a build thread but I have been having issues uploading images to the Nasioc host. But I am slowing adding more info.
https://forums.nasioc.com/forums/sho....php?t=2937433

Oh, and I found this $50 controller for the BRZ EPAS on eBay. However, it is Portugal.
https://www.ebay.com/itm/144032280559

I also found these connectors that look like the BRZ connectors so you might be able to make your own power harnesses.
https://www.ebay.com/itm/265072946013
https://www.ebay.com/itm/265072955344

I have a few odds and ends to fix but I'm kinda focused on my tall boi shifter now.

If anyone wants that controller to adjust steering feel on the fly its no longer on ebay (not with this link anyways).
The Portugal guys website who makes this is...
https://www.brunosteering.com/produc...ller-kit-epas/


He also has a GPS based kit.

[ether947]

Another update.

I bought another EPS control module as I thought my earlier replacement was broken. It wouldn't shut off after turning the car off and I was afraid it would drain my battery. Or worse, it had a stuck relay and would potentially catch fire. However, the new module did the same thing. Eventually, I figured out that the newer modules will keep the P/S system running for a little while after key-off before killing power. My guess is this delay is a feature and not a bug. After about 5 mins, you can hear the relay click off.

I decided to redo some of my wiring as it was more of a proof of concept setup. So far, I haven't had any cutout issues!! I also removed the Bruno controller and run the setup on minimum power assist. After driving this car without any power steering at all, the default assist feels like plenty.

I am still working on building a new harnesses with brand new wires. I found the pins for the control signal connectors on Digikey. They aren't 100% the same as the OEM pins have a gold looking plating on the end but those aren't available. However, they fit and lock into the stock connector.

https://www.digikey.com/en/products/...311-7/15902834

I will be using Deutsch connectors on the other side. Wiring is 22AWG if you are curious.

I will probably relocate the control module in the trunk. Right now it is under driver's seat and I am worried that someone will kick the harness and I will lose power steering again. I rarely have passengers in the back, but it is bound to happen at some point.

Originally Posted by sorrowfulkiller

If anyone wants that controller to adjust steering feel on the fly its no longer on ebay (not with this link anyways).
The Portugal guys website who makes this is...
https://www.brunosteering.com/produc...ller-kit-epas/


He also has a GPS based kit.

Thanks for the updated info.

[customatic1969]

Hello I am working on a prodject and am consider using an electric power steering.
and think about the corolla e120 unit that u are us in ur epas thred.
the requerd relays what are these, and does the unit work in failsafe mode.
there is a steering angel sensor on later units is it required?
and last what pin should i feed power to make it work in safe mode.
thank u for reading hope u can awnser my questions,
have a good day

[ether947]

Almost a year update.

No issues whatsoever since my last update. I am honestly a little surprised I fixed it. lol. I am still running the system with the default power assist, although I wouldn't mind a little less assist. If I pick up a controller, I will probably get the AGT controller. I like that they have a screen readout now.

https://www.agtengineering.com.au/pr...ering-emulator

[Hyper]

so it takes factory ABS signal and converts it to canbus the EPS module understands... pretty cool