UrS6 - Fuel Pressure Regulator Query

[macspring]

Why is the fuel pressure rating lower on and ADU at 3.8, compared to 4.0 on an ABY ?

Thanks.

[UrS4boy]

Why is the fuel pressure rating lower on and ADU at 3.8, compared to 4.0 on an ABY ?

Why do the ADU injectors flow more than the ABY injectors at the same nominal 3.0 Bar pressure? (Answer: Because they are bigger).

So the combined answer is "because". "Because" that is the combination (Porsche-sourced green top injectors and 3.8 Bar fuel pressure regulator) that the Porsche-engineers liked for their performance goals, e.g. 315 PS crank, via dyno-tuning. For a given injector and fuel pressure across the injector, it's all about the duty cycle.

AAN/ABY injectors are smaller (flow less at 3.0 bar) so the 4.0 Bar FPR is used to up their capabilities at bit. Even with that pressure boost, they sort of max out somewhere around 280 PS.

[macspring]

Perfect, understood.

Thanks again Dave.