Mapping HSV duty cycle against speed / load / inj Dc??

[max_torque]

Hi,

I am about to set up a full system (race pump, accumulator, HSV, 4 x 0.3mm jets, DDS2) on my turbo rally car, which runs with a MoTeC M8 engine management system.

Basically i drive the HSV from a spare PWM driver, and i can select what parameters i use for the 3D maps axis.

1) Option 1: speed and load. X axis is engine speed, Y axis is MAP. This would be a direct mapping of HSV duty verse these to axis, allowing me to tailor the water injected percentage to meet requirememts against plenum pressure.

2) Option 2: speed and fuel injection duty. X axis is engine speed, Y axis is fuel injector duty cycle. Effectively map water injection mass as a ratio of fuel flow.

I correct fuel injection using both a wide band lambda sensor & pre turbine EGT (once it hits a my EGT limit) (engine is mapped to LBT (approx 0.89 lambda, and uses EGT sensor to overfuel for component protection as necessary)

If i use option 2, i effectively can map my water injection like my fuelling, i have a target AFR, and i could now use a target WFR, i.e. the water injection mass flow would be corrected automaticaly for changing conditions such as BARO, IAT, etc.

Anyone tried this method?