Car appreciation... the aesthetics, the engineering, etc

yeah for similar power outputs turbo's are generally more economical.

ie my Subaru Legacy 3ltr flat six gets low 20's and produces 245bhp, whereas the JDM Legacy 2.0ltr twinscroll turbo produces 280ish bhp and gets high 20's... they have exactly the same body (apart from intercooler scoop) and very similar weight

Combined cycle though, innit.

If I pootle along at 3,600rpm in fifth with the wastegate open then I get 30-40 mpg.

A four litre V8 doing the same is going to burn more fuel at that rev/speed/load due to a bigger displacement.

However, the entire point almost of a forced induction engine is that when the engine is seeing 20psi above atmospheric and the injectors are dumping in enough fuel to maintain an AFR of around 12, then you are generating more power than the V8 and you are doing so by burning more fuel than the bigger engine could burn.

Of course, this comparison goes totally out of the window if it's a big block, or something high revving with an angry cam.

My combined cycle average (totally disregarding track/closed road use) is 22-24mpg, as long as a lot of that particular tank of fuel is spent on the motorway.