As rising fuel prices and CO2-based taxes hit, the 'umble turbocharger is fast becoming a great way to squeeze a quart out of a pint pot - just look at how widely Volkswagen uses its 1.4-litre super- and turbocharged petrol engine across its range these days, or try the new 1.4-litre turbo in Fiat's Bravo. And, of course, no self-respecting diesel does without.