Thunderace EFI - Day 10 using MSExtra 3.0.3u

Well I got MegaTunix going early next morning, and all I did was upgrade to the "git" version, and it worked thereafter.

Anyway, I’d thought I'd test it out on the bike, so another trip was needed to look at the compensation issues. The conclusion is this whole battery voltage injector compensation thing is quite testing, which is compounded by the poor state of the battery, but this is a good learning process and can only mean better refinement.

I found I am using really small values for the adjustment now 0.050 msec/V from the default of 0.200msec/V, but obviously I am playing around with the Req'd Fuel & Injector Opening Time. It looks like I might have to change the VETable resolution, because at stoich the difference between 16 or 17 in the VE bin sends it too rich, so I'll be doubling the numbers and halving the fuel.


I did manage the above, but I think the compensation was 0.00msec/volt, but under cranking it was a big starting issue, as the 9.0V under the starter, affected the idle and ASE quite a bit. I rounded off my hour or so of tweaking by adjusting the acceleration enrichment tapers, after switching AE on of course.

However being an Alpha-N/ SD blend, I spent quite a bit of time reducing my very small part throttle openings, as they were far too rich, which means modding VETable 2. This actually works rather well without having an acceleration enrichment enabled, and I can see this is a useful tool to smooth out very small throttle transitions. It would be a lot more useful to do this under some load, but this bike isn't on the road yet, and the rear end is being overhauled I can't dyno it, as the wheel and other stuff is pulled out.

I also played with the TPS/MAP blending and the thresholds, and got good "very sudden snap open throttle" response by lowering the MAP threshold from 150 to 120. I also have very little ramp slope/gradient on my AE curves, as I am running way too rich under acceleration, and this is a lot different to how I started.

I am using 3.0.3u at the moment, and surprisingly I did notice the ASE light coming on when blipping the throttle, and revving the bike, which I'll be looking out for again next time I play with the engine, as it could be a bug.

Finally, I got MegaTunix 0.9.22 hooked up to the engine as a parallel development in OSX on the MacBook Pro, and other than a need to rework the gauge limits/layout, it is surprisingly fast and quite a bit different to TunerStudio. Obviously I am used to the latter, but MegaTunix looks like another useful tool in the MicroSquirt tuning library.

Next up is rework the .ini file so that the AFR readings can be used to tweak the VETable automatically. I probably need to restrict it to one table, VETable2 as MAP fluctuates quite a lot with very small throttle openings.

Tables look like this now...and the refinements are just right of idle around 65-75 kPa (fuelload% in this graph below), in VETable2.