most stationary engines, like in powerplants and mine, have turbo's with an impellar size of around 1-1.5m across, so big they actually have they're own oil sump and pump...
the 40tonne trucks ahve a smaller one (bout the size of a small human crouching) and these are rated at about 3000hp i think, all mapped to dilever boost at around 1000rpm to about 2400, which is redline for the big capacity deisals