Iveco 2.8t more power?
Iveco 2.8t more power?
The wastegate is suppose to limit boost. Not delaying spool up time. I don't know about Iveco engines but sometimes on continuous speeds the waste gate is kept open on purpose to limit back pressure and unnecessary heat build-up. But this is delaying spool up time a little bit when you're on the move and want to overtake or something but I doubt it's even noticeable.
Turning up your pump is indeed consuming more fuel. But so is everything when you want to increase power. More power means more fuel. Even if you could get instant boost it's going to consume more fuel because it needs more fuel for the power.