Lets talk a little about the tuning software.
The tuning program that Megasquirt uses is TunerStudio, and there's a datalog viewing program called MegaLogViewer. I believe the basic versions of both are free.
Here's the "dashboard" in TunerStudio. I've got the program set to record 45 snapshots per second through a USB cable that comes out of the Megasquirt computer in the Jeep. The gauges on the dashboard update in real time as I'm driving. You can choose to record or not. If you record you can then later open the datalog in MegaLogViewer, which has some very powerful visualization features to make sense of the massive amounts of data. The small window that is open in the image is the volumetric efficiency table which you have to develop for your specific engine. it's essentially how much the cylinders are filling up with air for a given manifold pressure and RPM. This VE table is iteratively honed in from datalogging, or by using TunerStudio's Autotune feature which can can adjust it in real time while driving and get pretty close using feedback from a wideband o2 sensor.
Here's some data visulization in MegaLogViewer. You can plot any 3 data channels against each other on a "2.5D" graph. I've got nearly a million snapshots displaying on the graphs from datalogs recorded in August 2019. The left side is showing RPM on the X axis, manifold air pressure on the Y axis, and the "Z" axis is the color of the cells which is manifold air temperature. You can see that boost starts building right off idle at 900 RPM, reall goes vertical fast at 1900 RPM, and hits full 11 PSI boost by around 2700-2800 RPM.
The graph on the left hand side is showing RPM on the X axis, fuel injector duty cycle on the Y axis, and manifold air pressure (in KPa) as the Z axis (color). The Jeep is running the factory 3 bar (43.5 psi) fuel pressure regulator and a 190 LPH (or whatever it is) Walbro fuel pump. I'm running some unnecessarily big 60#/hr (630 CC/min) Siemens Deka fuel injectors. The max duty cycle is 64%; using an online horsepower calculator this is about 250HP worth of fuel. This seems high and I'm guessing it's more like 230hp, which is about double the factory HP of 123. And this is all on a motor that is curiously only making 90psi compression on every cylinder, when it should be more like 120 psi at this elevation. I'll probably look into whats going on with that and see if I can rectify it and gain a nice bump in power.
Here's MegaLogViewer again showing a histogram of RPM vs MAP, vs closed loop fueling correction based on the wideband o2 sensor. You can see that it's dialed in pretty well. I can get any AFR that I command for a given RPM and MAP by using the AFR table in TunerStudio. You can also see that I've binned the histogram's X and Y axes non-linearly. The bin spacing is based on which areas the engine spends the most time in. This was determined by loading a several million snapshots or about 2 years worth of datalogging and seeing which areas had the highest hit counts. This allows me to have greater resolution in the idle and cruising cells by sacrificing resolution near redline where the engine is just acting like a big dumb animal anyway.
Anyway, it's taken a while to get it finished since I've only had 2 months out of the summer off from school, but the Jeep drives beautifully and pulls hard. Everything has been perfectly reliable and I've just been enjoying driving it since I put the intercooler on about a year ago. The engine loves the boost and it loves to rev to redline now. Before the turbo it felt like it was going to rattle apart as it revved up and felt like it was making less and less power. This honestly the most fun vehicle I've ever driven and the looks on people faces when they hear all these crazy turbo noises is priceless.
