The Koenigsegg CCXR is an "environmentally-friendly" version of the CCX, powered by a modified twin-supercharged V8 engine from the CCX, converted to use E85 or E100 ethanol fuel as well as standard 98 octane petrol. When run on regular petrol, the CCXR develops 806 bhp (601 kW), but when the car is run on E85 Biofuel, the CCXR develops 1018 bhp (759 kW). Weight-to-power ratio is 2.76 lb/hp. Torque is 782 ft·lb (1060 N·m). The CCXR can achieve 62 mph (100 km/h) in 3.1 seconds. Christian von Koenigsegg is quoted as saying, "Our engineers couldn't quite believe the figures when we tested the car". The increased power is a result of the cooling properties of ethanol in the engine's combustion chambers allowing for a higher pressure in the cylinder and the biofuel having a higher octane rating of 113 RON compared to 95 RON for gasoline in North America and 100 RON for gasoline in Europe, although the CCXR burns slightly more fuel than the CCX with about 15 mpg (17L/100 km). The only changes to the engine are modified fuel injectors, upgraded fuel lines and piston rings and a higher boost setting on the superchargers. Koenigsegg say that it will go 259 mph, making it the fastest production car in the world.  In March 2009 the CCXR was chosen by Forbes to be one of the ten most beautiful cars in history.