8. BMW 4.4-liter S6344TU Twin Turbo V8
Behind this long, uninspiring name is a world-class V8 powerplant responsible for the stellar performance of the BMW M5, X5 M, and X6 M. In terms of numbers, this 4.4-liter twin-turbo V8 delivers 575 HP and 500 lb-ft of torque. It’s quite odd to see a twin-turbo V8 from BMW. BMW is a company they built on the straight-six naturally aspirated engine. However, modern times ask for different engines and BMW must deliver to stay on top of the car world. This highly-advanced unit includes light materials and has two turbochargers, one for each side of the engine.
Despite producing enough power to make the M5 one of the fastest sedans in the world, a group of enthusiasts discovered the S6344TU delivers even more horsepower than advertised. Independent dyno testing shows this twin-turbo V8 produces up to 620 HP, which is more than the 575 HP the factory claims.