Lude Generation

(crossposted from prelude power forums)

firstly, I am not expecting any drop-in replacement, simply calling for anyone with knowledge about how these systems work to provide information.

I've been thinking of using modern 4WS systems to upgrade/modernize the 4WS in my 94 prelude, I've been considering an engine swap and have all but written it off as it would undoubtedly lead to issues with 4WS, as it's not a mechanical system in our cars. obviously, if I were to swap the engine I would more than likely switch to a standalone ECU(making sure to get one that would support something as obscure as 4ws) my main question is this, how EXACTLY does the 4ws system in a stock prelude work? I know that the power steering fluid gets sent to the rear unit, where it's measured by the 4ws computer, which sends a signal to the electric motor. does this mean I can bypass the hydraulic sensor, and the 4ws computer and hook the motor up to a standalone ECU? Would I need to keep the sensor intact and reroute the wires for it to the ECU so it can determine the steering angle? or would I be better off going with a complete aftermarket solution and fabricate a custom mount for an off-road 4ws motor, then limiting it to stock numbers (or figure out my own angles) in an ECU that supports that hardware.

Hi and welcome.

The 4WS is totally independent from the engine and ECU electronics (save that it does rely on a VSS signal).

There is no fluid going to the rear, it is fully electronic. There are no fluid sensors.

Effectively, the front steering rack has an angle sensor, as does the steering wheel. These are used to send signals to the 4WS ECU which drives the actuator in the rear rack, its position is then confirmed with 2 more angle sensors in the rear rack. The system also uses the ABS sensors on the rear of the car, though there are 2 different 4WS ECUS available, one to be used if the car has ABS and one to be used if the car does not have ABS.

I run a Hondata ECU, have deleted my ABS and still rock 4WS awesomeness.

The full system is detailed in the Honda service manual. Download 62SS000.pdf - page 17-3 onwards.

i mustve misread the diagram then, could have sworn fluid got sent to the rear, but hey! this just makes my job easier. I'm going to look into the pinout for the sensors and the electric motor and see if i can replace the stock 4ws computer with something meant for offroad vehicles. the main goal of all of this is to improve 4ws performance (turning speed/increasing angle), increase life of 4ws by finding aftermarket solutions to broken parts, and being able to manually control the steering angle (crab walking a prelude would be pretty cool IMO)