aero901 Posted October 7, 2023 Share Posted October 7, 2023 Anyone know if there is a Subaru electric power steering rack from a newer model that can be swapped into the Gen 4 chassis relatively easily? Ideally, one with a quicker ratio than 1:17, but willing to go with whatever. The boots and seals on my current rack are toast, the pump is leaking, 20 year old hoses are cracking (basically needs a total system replacement). Can't keep fluid in it more than a couple days. An electric PS conversion/swap may be the cheapest option, if available, at this point. And it would free up quite a bit of space in the engine bay for "future projects." EPS units from a Prius and other similar vehicles seem to be a popular option for other projects I've researched. The motor is integrated into the shaft between the rack and steering wheel though so not sure if there would be enough space under dash while maintaining a stock-ish interior. Link to comment Share on other sites More sharing options...
blackobxt Posted October 8, 2023 Share Posted October 8, 2023 To my knowledge this has never ever been done. If you’re willing to swing for the fences I’d say go for it but the path will probably be a total bitch with a heaping spoonful of disappointment. Grab yourself a 2015+ Sti rack and bolt it in. Much faster ratio and proven to work great. I got a used one for just under $400 in close to new condition. Link to comment Share on other sites More sharing options...
blackobxt Posted October 8, 2023 Share Posted October 8, 2023 Also to note, the power steering on these are pretty compact and I’ve never really seen the pump or reservoir impede on any “activities” so any freed up space will be pretty minor. Link to comment Share on other sites More sharing options...
aero901 Posted October 8, 2023 Author Share Posted October 8, 2023 You're right those are pretty compact as is. The hoses were my concern since they seem to be taking up space that would better serve FMIC piping and turbo stuff. The ideal solution would be the quick ratio rack with the column style EPS. Link to comment Share on other sites More sharing options...
Haze Posted October 9, 2023 Share Posted October 9, 2023 (edited) Do a search for "Volvo electric power steering conversion ". There were a bunch of Volvos that used an electrically driven hydraulic PS pump that can be adapted to pretty much anything to replace the belt driven pump. You would still have hydraulic lines but may be able to route them somewhere out of your way. Combine that pump with the STi rack and you have most of the advantages of a full EPAS setup with next to none of the problems of getting it to work. Edited October 9, 2023 by Haze Link to comment Share on other sites More sharing options...
aero901 Posted October 10, 2023 Author Share Posted October 10, 2023 Cool, didn't know about the Volvo/Ford units. After looking into it a bit, I'm going to steer clear of them for a couple reasons though. The pumps draw a lot of current. Reports of up to 70 Amps at max effort and this might require an upgraded alternator if used in a high performance environment. The column mounted EPSs max out around 20 Amps when stalled. Looking to stay away from hydraulics in general since they are more complicated with more points for failure and maintenance. The pumps also seem noisy in the videos I've watched? Could just be a video sound equalization thing though? The motor/reservoir assembly is larger than the current stock pump/reservoir which is the opposite direction I am looking to go with this. They are relatively tall and need to be mounted vertically to work. Not seeing a good spot to mount it under the hood without moving/removing other stuff... Link to comment Share on other sites More sharing options...
KZJonny Posted October 10, 2023 Share Posted October 10, 2023 Just being devils advocate a little, but do you really think that the column mount unit from a Prius will hold up to the use case in a turbo sport sedan? You’re talking about FMIC, so I assume this car will get used a little. Our cars are ~600lbs heavier, and I assume you’ll have wider and more aggressive rubber on it that the skinny little tires on a fuel sipping Prius. Genuinely curious the examples you’ve found are in the category of vehicles that are driven aggressively, and if there are any longevity reports. Link to comment Share on other sites More sharing options...
aero901 Posted October 10, 2023 Author Share Posted October 10, 2023 (edited) Good point. Something to look into for sure. I know the column mount units are commonly used in rally projects which see about the most extreme duty of any motorsport. Granted, the cars weigh less but they also commonly use a steering multiplier which puts even more load on the EPS motor. Need to find some hard numbers though. Edited October 10, 2023 by aero901 Link to comment Share on other sites More sharing options...
silverton Posted October 10, 2023 Share Posted October 10, 2023 I think you're going to need an uprated alternator no matter what electric power steering system you go with. Link to comment Share on other sites More sharing options...
KZJonny Posted October 10, 2023 Share Posted October 10, 2023 49 minutes ago, aero901 said: Good point. Something to look into for sure. I know the column mount units are commonly used in rally projects which see about the most extreme duty of any motorsport. Granted, the cars weigh less but they also commonly use a steering multiplier which puts even more load on the EPS motor. Need to find some hard numbers though. Yeah man. I just very much doubt that they are using the same units (readily available tho they are for us...) as the Prius. I would suspect it would be the sort of thing they are using for say, the GR Yaris/Corolla. Similar in concept, but I'd be willing to bet they aren't at all the same on the inside. Not saying don't go for it at all, just thinking that it would a pain in the ass to do all the fabrication and the like to make it work, only to find out that it's underrated for the task, etc.... Link to comment Share on other sites More sharing options...
seanyb505 Posted October 10, 2023 Share Posted October 10, 2023 7 hours ago, silverton said: I think you're going to need an uprated alternator no matter what electric power steering system you go with. You could probably run a second alternator with the new room for activities. 2 Link to comment Share on other sites More sharing options...
silverton Posted October 10, 2023 Share Posted October 10, 2023 I suppose an alternator could go in place of the power steering pump but I think that defeats the OPs purpose of "future projects" Link to comment Share on other sites More sharing options...
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