MegaSquirt Modifications

Ok, so there are some modifications that I want to make to my MegaSquirt - it’s pretty cool to start with - but I want injection control and a few other goodies.

The first one I want is “switchable tables” which means I can choose between two boost/fuel/spark maps by flicking a switch. Another option is single or sequential shift lights - either a single “set off when at this rpm” or sequential ones, hitting green at mid-normal rpm, orange/yellow at shift, and red at over-rev. This is all user-selectable and so forth, and I’ll probably hide it somewhere in a modified section of my dash, with a switch to turn it off when I’m not using it. Using the extra outputs, I’ll also be able to setup an automatic switch based on engine parameters for the thermofans I want to use, and possibly some other things.

Software-wise, the MegaSquirtNSpark-extra firmware allows for quite a few things, including a hard cut for overboost, which will be good for testing with the supercharger.

An advantage of using the wideband oxygen sensor is that the code allows for air:fuel ratio mapping so that the system will attempt to slightly retune itself where needed to aim for set A:F ratios, saving the engine from lean conditions.

Another thing I’ve been looking at is the over-run fuel cut - allowing for the system to cut the fuel when you’re coasting with the throttle closed - normally when you’re engine braking or coasting to a stop.

MAPdot is a system of creating what could be termed an accelerator pump for EFI setups - compensating by increasing the duty cycle of the injectors when one quickly applies the throttle so that a lean condition doesn’t occur by the sudden rush of air.