For the 14R, this was of no interest since this engine's supercharger (in its second version with axial entry, from the 14R 04/05) had very high performances, with an efficiency close to 80%.
For a frame of reference and out of curiosity; how does that 80% efficiency rating compare to other superchargers around the world during the same time period, on radials or otherwise?
From everything I've read, I'd imagine it would be a good bit better than the 801's supercharger and leaps and bounds better than the superchargers on Italian radials.