Modifying Hicas

[HtwCHACtkh]

Hello,

I am interested in modifying HICAS to behave in a more controlled way. I've done a search for it and the closest thing I found was a thread from 6 years ago which is very interesting but all the pictures are now dead. =( So I was wondering if anyone has any experience, advice or an ECU pinout for the R33 HICAS ECU in English. =P

Things I would like to try implement at this stage:

1. Switch to toggle HICAS 4WS while still retaining power steering.

2. Modify speed sensitive power steering much like this.

Since the 4WS system is quite advanced I don't really want to f**k too much with how it behaves when it's running, it does the job perfectly fine on the street.

*3. I might consider doing is trying to make the rear wheels turn opposite to the front wheels at very low speeds to assist parking; however as I uneducated on how the HICAS ECU works at the moment I'm not sure if this is possible or advisable. Maybe have a switch/toggle all this.

Why? Well 1. Is arguably cheaper/easier/better than a lock bar. 2. Personally preference really, I can move my steering wheel with my pinky at the moment and I find that too light. 3. Funzies? Have you ever tried the HICAS diagnostic mode when the rear wheels move when the car is stationary, it feels funny. xD

[Moodles2]

If you haven't read this thread already, you might be interested: http://www.skylinesaustralia.com/forums/topic/332068-help-me-install-my-new-hicas-controller/

[HtwCHACtkh]

If you haven't read this thread already, you might be interested: http://www.skylinesa...cas-controller/

Cheers Moodles2,

The pin out lead me straight to the power steering solenoid which I can tap into pretty easily then.

So this goes between the fail safe valve and does something there. I also did some research finding that 'fail safe' mode locks the speed sensitive power steering assistance to that of which is approximately at 176km/h from this thread on Skyline Owners. However if that was the case, it would be a pretty crappy system if it simiply just cuts that off - does anyone know what's inside of it?

I'm going to try simply unplug the actuator controlling the rear wheels to see if any HICAS fault codes come up as a simple way to stop the rear wheels from moving.

The more I learn about HICAS the more I think it's a stupid idea to try mess with the speed input to the ECU to try control the system manually. So feature three is completely out of the question... for now.

[GTSBoy]

Faeture 3 was always completely out of the question.  How far and what direction the rear wheels turn is at the complete discretion of the HICAS ECU.  I'm not entirely sure why you'd want to achieve it anyway.  Mazda and Honda had their not-nearly-as-good 4WS systems at about the same time do it purely because they were FWD and therefore had relatively poor turning circles.  The low speed countersteer was only to try to offset that.  Skylines have a reasonable turning circle as it is.

HICAS only gives any countersteer at the beginning of a turn-in event to try to generate some slip angle earlier in the process (by throwing the rear end outward) then it reverts to normal direction steering.  But it's really only good for a standard car at 7/10 or so.  If you stiffen the chassis and suspension up and drive hard, then you've already made the car able to generate slip angle early in the corner, plus made it better able to be controlled via the steering wheel, and the last thing you need is HICAS semi-randomly making decisions about which direction the rear wheels should be facing.

Which is a roundabout way of saying that any effort spent on the HICAS system should be towards deactivating/removing it, not trying to tune an inherently untunable and ultimately unnecessary system.

Edited November 28, 2011 by GTSBoy