The Koenigsegg CCXR is a mid-engined roadster from Swedish car manufacturer Koenigsegg. The CCXR is 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. Besides the use of ethanol fuel, the only changes to the engine are modified fuel injectors, upgraded fuel lines and piston rings, and a higher boost setting on the superchargers. The increased power of the CCXR, compared to the CCX, 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.
The designer of the CCXR, and founder of Koenigsegg, Christian von Koenigsegg is quoted as saying, "Our engineers couldn't quite believe the figures when we tested the car".
In March 2009 the CCXR was chosen by Forbes as one of the ten most beautiful cars in history.