EPAS in my Mirage

[Blueovalz]

Perhaps not very relevant to the Mantas on the forum, but maybe it will be useful to some.

Recent track days have been painful in that old rotator cuff repairs have been re-damaged, and now I've got to find a way to ease up the steering effort on my Mirage. My choice after some discussion with another member and some YouTube video review, is the Prius EPAS mainly because without the usual inputs to the EPAS control module, this system goes into a Fail-Safe mode, which appears to be a constant assist rather than one based on vehicle speed, etc. I will try to provide as much documentation as possible for those that may wish to replicate it in some fashion or another (my Mirage has significant changes under the dash from the norm).

Part of my problem is that the steering rack I'm using is a 911 rack, which is has a tight ratio (1.5 turns lock-to-lock), requiring high effort, but very responsive to input. I am also using a 930 (or >'75 911) steering column due to its simplicity and compact size. This is what I'm currently running in regards to a steering column:


The Prius EPAS ('04-'09) which I immediately cut up to see what potential it had for being shortened from the OEM length of 17", to a required length of 9" (Porsche column length), or 11" including the quick-release mandrel:


Comparison of the two columns to determine what was needed to shorten the shafts to get down to 9":


Under-dash structure with the Porsche column removed, and the EPAS mocked into position: