Wait, why an MS3 upgrade?
So, I’ve decided to upgrade the Megasquirt MS1 to an MS3 daughterboard, MS3X expansion card and the internal knock sensor module. The main board that I used is a V3.0 board so upgrading was not difficult however I had a number of custom modifications which needed removal. Almost all of the functionality gains from the modifications were picked up natively in the MS3X expansion card.
One modification I did retain was the Q16 high current ignition coil driver. This was originally driven from the ‘LED’ outputs which are now used to support the knock module. I had to find another way to trigger Q16 so I connected the ‘Spark A’ logic output from the MS3X card through a 120Ω resistor to the IGBTIN point on the V3 board. If this mod is succesful I will put together a full write up.
Anyway, giving further context to abandoning the MS1. If you follow my youtube channel you will see the amount of effort used to tune to the car. The car is still difficult to operate with the custom made Whitleytune manifold. Working through this with the help of much more experienced tuners the MS1 just isn’t up the task for the following reasons:
- VE and ignition tables lack sufficient resolution for smooth transitions at low amounts of throttle using the Alpha N algorithm
- Injector data is limited to single entries treated as linear which modern day injectors rarely behave in a linear fashion eg. dead times
- poor noise filtering for trigger inputs
- firmware has not been supported for a long time
- calibration of sensors requires rewriting firmware using an early Windows based executable (I work on Apple devices)
So what benefit does upgrading to and MS3 and MS3X give me? Well firstly firmware that is currently supported and likely to be supported for a long time for starters! Access to 16×16 tables with option to expand the tables, 8 injector and 8 ignition channels and even individual cylinder trimming amongst other things.
Those who have been around L6s long enough know that cylinder 5 and 6 run hotter and can benefit from a little more fuel and a bit less ignition advance. While I have recycled the Q16 ignition coil driver, I will likely swap to COP as some stage.
I have made a YouTube video of the upgrade along with the Q16 logic trigger. Check it out below. Where to from here? Testing the board proper then rewiring the recently completed wiring harness in the car….lots of fun!