The engine that is fitted on the Veyron is going to be used on the luxury sedan that Bugatti is planning to come up with. The engine therefore would be the 8.0 liter W16 which can deliver 1001 hp and having a top speed of 400 kmph. The Veyron incidentally is the fastest production car that one would get in the market as on date. According to German newspaper Spiegel, the car is going to be based on the Audi A8.
However, being a sedan the car would be heavier by weight and therefore one would not get the same power results as the Veyron from this engine fit on the new car that has been named Bugatti Galibier. The Bugatti Galibier would therefore get only 800 hp of power from the engine which has the capability of delivering 1200 hp or 882 KW and a max torque of 1500 NM.
The Veyron Supersport model which is the fastest car in the market today can do an average speed of 431 kmph or 268 mph. but to protect tires the Super Sport version of the car has a limit on top speeds of 415 kmph.