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 comparison graph of Autovac and Grav-Vac petrol feed systems on a 20 HP engine.
| Identifier | WestWitteringFiles\Q\February1927-March1927\ 103 | |
| Date | 29th March 1927 | |
| AUTOVAC AND GRAV-VAC PETROL FEED. TESTS CARRIED OUT ON A 20 H.P. ENGINE WITH STANDARD CARBURETTER AND INDUCTION PIPE. FUEL RAISED 32" THRO' A PLAIN PIPE .280" DIAM 6FT LONG. TESTS AT FULL AND HALF THROTTLE. GRAV-VAC : ---- AUTOVAC : ——— PETROL DELIVERY PTS/HR ENGINE R.P.M. INDUCTION PIPE DEPRESSION IN Hg HALF THROTTLE FULL THROTTLE FULL THROTTLE 5.3" 4.5" 3.9" 3.0" 2.25" 1.6" 1.55" 1.25" 1.05" | ||