Top-level rally cars in the WRC are currently restricted to just 1.6 liters. Here is a look at VW's reigning double championship-winning turbo four-cylinder.
This little engine puts out an incredible 313 horsepower at 6250 rpm and 317 lb-ft of torque at 5000 rpm (VW's official figures are 318 PS and 430Nm). This is with a 33mm restrictor on the air intake, too.
It's incredible how much power these WRC cars can produce from so little displacement, with so much response (thanks to anti-lag keeping the turbocharger perpetually spooled) and with so much reliability.
There's more information on these engines on VW Motorsport's own website, and if you're interested go .