The world's most powerful four-cylinder turbo.

The turbocharger experts at BTN Turbo frequently update us about advancing turbo technology – especially how it’s extracting more and more power from smaller engines. For a dramatic demonstration of this, look to the latest Mercedes A45 AMG model.

Thanks to its BorgWarner twin scroll turbo, this high spec A Class model has the world’s most powerful production four cylinder engine. From just two litres, it produces over 350 bhp (265 kW) – a quite incredible 180 bhp (133 kW) per litre. Maximum torque is a mighty 331 lb/ft (450 Nm), available from low revs for spectacular acceleration.

This is achieved by an exhaust system carefully tuned to provide optimum back pressure and gas temperature, and a twin scroll turbo that delivers maximum boost pressure of 1.8 bar. Air-water intercooling keeps the highly compressed charge air cool, for efficiency and reliability.

As BTN Turbo points out, the effectiveness of the A45’s turbocharged setup is shown not just by its prodigious power output, but also by an average consumption figure of 34 mpg and Euro 6 emissions compliance.

With over 18,000 OE new and OE replacement turbos in stock, BTN Turbo has a turbo for everything from a JCB to an AMG Merc.