Highlighted improvements for the 2006 Hummer H1 to create the Alpha designation include more power from a new engine and improved fuel economy. A 6.6-liter, turbodiesel V8 producing 300 horsepower and 520 lb.-ft. of torque, and that also improves gas mileage, powers the H1 Alpha. The 2006 Hummer H1 Alpha is offered in both Open Top and Wagon versions.