Boost and table switching

[moncharleskey]

Hello, finally getting back on my project so here are a few details. Running MS3 + expansion card on a 4cyl 1.8l with independent coils and a supercharger. I currently have my charger set to trigger above a certain TPS threshold. The problem I'm running in to is that this makes for some really dirty fuel maps and auto tune has a hard time handling it. I'm wondering if there is a way to run duel fuel maps and have it switch fuel maps when the supercharger is activate so I can avoid running super rich at idle or hitting a lean spot with the charger running. Anyone have any suggestions here? On a separate computer, so I'll post the MSQ in just a minute.

[moncharleskey]

Well, after doing some digging I was able to set up my tables to switch based on kPa. I changed my super charger trigger to kPa to keep them in sync, but I'm wondering if I should set the table switch for the same value (Charger kicks on at 80kPa) or lower/higher. I don't want to run lean when the charger kicks in, so I'm thinking I could set it a little lower, possibly as close as 78 kPa. Anyone have much experience with boost table switching?

MSQ attached for reference.

[Matt Cramer]

Another option would be to have some way of confirming the supercharger is active, and if so to engage a hardware table switch.

[kaeman]

how are you enabling the charger, does it have an electric clutch, is the megasquirt turning on the charger? If you are having the charger turn on at a certain tps value then you should be able to have that value do the table switching for you.

[moncharleskey]

The way I have it setup at this time the charger is trigger through a relay by the MS3. I have it triggering based on kPA, but it's not ideal. With TPS the kick off for the charger is too rough, but with kPa it doesn't like to kick off when it should due to the increased pressure on the outside of the throttle blades. Anyway, I set my fuel maps to switch at the same point, but it's not smooth as the charger isn't necessarily off below that value. I see where you can use a hardware input, so I'm thinking about running a wire from my coil into the MS3 to switch that way.

Is there a way to use the hysteresis value to make the charger cut off slightly above the threshold? I've got it set to 85kPA currently.

Thanks a lot guys!