Did I understand correctly that the stock LPFP controller overheats when the duty cycle increases beyond certain point?
In that case the controller could probably be strengthened by improving the cooling.
The current draw of the fuel pump increases at higher duty cycle so the heat caused by the increased currents would logically be the background of the issue.
I assume (and hope) the control unit doesn't have a LDO inside it but uses PWM modulation from start to end?
Based on ELSA the fuel pumps should flow as follows (minimum):
200-265hp (1K0919051AS) pump:
992cm³/min @ 10V
1240cm³/min @ 11V
1520cm³/min @ 12V
RS3/TT-RS pump (8J0919051D / E):
1600cm³/min @ 10V
1840cm³/min @ 11V
2120cm³/min @ 12V
So at 12V (~88% effective duty) the non-RS pump would be able to flow fuel only worth of 220g/s of air at 0.8 AFR (((1520/60)*0,741)*11,76)
Likewise the RS-pump would flow fuel worth of 308g/s of air per second at the same duty cycle.
Therefore at 100% duty cycle the absolute maximum flow for the non-RS pump would be around 355hp (crank)?
0.741 = Fuel weight (grams per cubic centimeter)
11.76 = 0.8 AFR
Maybe I'll source a broken stock controller and pop it open.
I got some background in VRM and PWM circuit design anyways
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