AEM EMS boost comp and "progressive" alcohol
I have been wondering about my difficulties tunning my AEM EMS with alcohol injection. Specificly durring spool up.
I figured it out!
While using boost comp tunning in the AEM EMS it is assuming your volumetric efficiancy remains for all intents and purposes relativly constant. If you have an alcohol injection system that "ramps up" over a range of boost then this totally screws with a system that is tunned in boost comp.
In boost comp tunning your fuel map for a given RPM at any boost level from 5 psi to 35 psi is a flat plane with no changes.... but with a suplementary fuel system (alcohol injection) that ramps up over a specified boost range your fueling needs change over that boost range rather than remaining constant. I figured this out when swapping out my spring in my wastegate I was running 18 psi instead of my normal 24 psi and my A/F ratios went from 11.0:1 up to 11.8:1 due to less alcohol being injected at 18 psi than is injected at 24 psi.
If there is a way to set up the SMC kit to either be on or off rather than progressive ramp up I will do so, otherwise I am going to set up my SMC kit so that my "full blast" alcohol injection is 1 psi above my "onset" boost pressure.