If it hadn't been for the fact that the Bentley 3 Litre showed little potential for a further increase in performance and the Bentley 6 1/2 Litre was prone to consume tyres at an alarming rate there might never have been a Bentley 4 1/2 Litre. Around the end of 1927 series production started of the new model with an engine designed to the proven pattern of the Litre. Collecting victory after victory on various race tracks the Bentley 4 1/2 Litre became highly successful. Based on the 4 1/2 Litre the sensational 'Blower' Bentley was created. A Roots-type supercharger by Amherst Villiers gave 9 1/2 lbs boost at 3,500 rpm. To run a Bentley 4 1/2 Litre Supercharged in Le Mans a minimum of 50 cars had to be produced for homologation purposes. Though the engine had been extensively modified lubrication was poor and cooling problems were immense. At Le Mans never and rarely ever in another major race Blower Bentleys finished first.

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