F88R Introduction

Following on from my post on Microsquirt Engine Management experience (here), at some point over the last year I came to realise that I was spending a lot of time, effort & money on trying to overcome the shortcomings of the Microsquirt ECU.

This had started with the CAN datalogger, GPS & IMU expansion and then extended to a CAN analogue input module for additional sensors. I also went on to looking at more suitable lambda sensor controllers to allow dual lambda input so that I could move the lambda sensors into the "2" part of my 4-2-1 exhaust system where the sensors could be installed per manufacturer's guidelines and remain installed permanently without fear of failure.

Meanwhile, I had purchased a Life Racing F88R ECU for another project so, instead of trying to modify and add things to make the Microsquirt work a bit better, I felt the best solution was to retire the Microsquirt once & for all and move over to the F88R which would ultimately provide a far greater level of control as well as additional I/O, on-board logging, on-board lambda drivers and no concerns over accuracy at high engine speeds.

Microsquirt v3 vs Life Racing F88R

The swap could have taken the form of carrying out minimal changes to the existing harness to swap the ECUs only. However, this approach would have left quite a few issues unresolved and would not have made full use of the F88R's capabilities. One of my long term goals with this project has always been to build a new wiring harness from scratch for the bike to fully integrate the ECU and other additional systems rather than treating them as add-ons to the original electrical system. I felt that the installation of a new, more powerful ECU presented the perfect time to fulfill this goal.

That is how an ECU swap quickly turned into a project in itself. Designing an entire wiring harness provided the opportunity to fix all the mistakes I had made with the Microsquirt installation and improve the overall electrical architecture of the bike. These included:

1. Implement a single, central fuse & relay box to control all power requirements on the bike. This would not only make power distribution more compact but would also allow me to change the way that different circuits were enabled on the bike, many of which did not exist on the original bike.
   
2. Integrate the Koso dash fully with the bike and ECU and thereby unlocking all functionally of the dash. The Koso dash is a nice unit with a lot of nice features but it is designed to be added to a basic motorcycle and to use its own sensors. This meant I needed to double up on some sensors such as coolant temperature so, as a result, the coolant temp reported on the dash was not always representative of the actual engine coolant temp, particularly during warm up. I decided that to allow the dash to report the data from ECU sensors, I would build a small dash controller module which would receive data from the ECU via CAN and then provide the necessary analogue signals to the dash. For example, coolant & oil temperatures could be provided using digital potentiometers to replicate the resistance of NTC sensors and engine & vehicle speed could be provided using square wave variable frequency signals from the microcontroller. The dash controller could also be used to flag errors from the ECU using the EOBD indicator and control the oil pressure warning light as a function of engine speed (provided an oil pressure sensor is installed). Provision was also included for shift light control.
   
3. Future proof the sensor & actuator configuration. The F88R has more inputs & outputs available than I am likely to need. I tried to anticipate what sensors I would be likely to fit to the bike and make provisions in the harness design so that the sensors could be added in the future without any wiring changes. Provision could be made for an eThrottle, accelerator position sensor, brake pressure sensor, 2off wheel speed sensors, fuel rail pressure sensor, multiple air pressure/temperature sensors, individual pencil coils, etc.
4. The Microsquirt installation evolved so much over time with sensors, networks and additional modules added. This is an opportunity to tidy up those evolutions and integrate them.
5. The Microsquirt ECU required some external modules to function correctly. Namely a lambda sensor controller and ignition coil drivers. With the F88R, these external modules can be removed.
6. The Microsquirt installation was always a trial installation. From the beginning I was never sure it would work or be viable so aspects of the wiring were just added on. Now the concept has been proven so there is no fear that this effort will be wasted. 
7. Use sealed connectors where possible/practical. As is typical of 1990's Japanese motorcycles, most electrical connectors on the OEM harness are of the unsealed type. Where possible or practical the unsealed connectors would be exchanged for sealed connectors.

I decided to take my time with this installation and spend a lot of time on planning & documentation before picking up a tool to ensure I got the best possible result. More detail of the process to follow in later posts.