Bentley Blower No.1 is a racing car developed from the Bentley 4½ Litre by Sir Henry "Tim" Birkin to win the Le Mans twenty-four-hour race. The car was developed into its current form for racing at Brooklands.

The Bentley 4½ Litre is a British car based on a rolling chassis built by Bentley Motors. Walter Owen Bentley replaced the Bentley 3 Litre with a more powerful car by increasing its engine displacement to 4.4 litres. A racing variant was known as the Blower Bentley.