From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Performance test data for car 12-GIV at Brooklands, comparing carburetter and bonnet configurations.
| Identifier | ExFiles\Box 102\1\ scan0030 | |
| Date | 13th August 1931 | |
| X5080. To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from F.Dodd. 13.8.31. X.788. X.1487. X.5080. 12-GIV AT BROOKLANDS. S.U. Carburetter - louvred bonnet (cut out closed). Air Temp. Water Temp. Lap Time Lap Speed MPH. 1/2 Lap mile Time 1/2 Lap mile Speed MPH. 21º 75º 2-12 75.12 24 secs. 73.17 21º 75º 2-12 75.23 24 " 75 S.U. Carburetter - louvred bonnet (cut out open). Air Temp. Water Temp. Lap Time Lap Speed MPH. 1/2 Lap Mile Time 1/2 Lap mile Speed MPH. 20.5º 70º 2-10 76.27 23.4 76.92 20.5º 73º 2-10 76.62 23.4 76.92 Standard Carburetter - louvred bonnet (cut out closed). Air Temp. Water Temp. Lap Time Lap Speed MPH. 1/2 Lap Mile Time 1/2 Lap mile Speed MPH. 19.5º 73º 2-18 71.97 19.5º 73º 2-17 72.49 24 secs. 75 19.5º 72º 2.17 72.49 23 " 75 Standard Carburetter - louvred bonnet (cut out open). Air Temp. Water Temp. Lap Time Lap Speed MPH. 1/2 Lap Mile Time 1/2 Lap mile Speed MPH. 19.5º 73º 2-15 73.45 23 secs. 77.25 19.5º 73º 2-15 73.45 23 " 77.25 | ||