ning
Elite Member
I was too, but after looking into it -Surprised they put in such a large engine to power the generator.
The 3.6L V6 is typically rated 275-305 HP.
They have it acting as the engine for a 130kW generator; 130kW = ~174hp. Assuming 10% power loss in the electrical generation, to generate 130kW needs about 193hp.
So, why are they using a 275-305HP engine to do a 193hp job?
Because 275-305HP rating is the max for that engine (depending on tune), and those engines are typically only at max output for a relatively short period of time - but the 130kW generator will be running not just occasionally (for extra boost) but for some lengths of time, when the battery needs recharging to some safe level, plus to run the truck itself when the battery is low or needs recharging.
So, they needed an engine that could kick out nearly 200hp for a decent amount of time, and that's not a 200hp peak output engine - that's an otherwise 300hp peak output engine, though this one is likely tuned for reliability and efficiency at the specific RPM range it's going to be used at for this generator job.
Essentially the answer is the same as "why does a 6.7L ps diesel make 475hp/1050lbft in the F350, but only 330/950 in a F550?" and the answer is that the F550's engine is expected on the average to put out more power (ie, higher duty cycle) and it needs to be able to handle that.