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 graph comparing Brake Horsepower vs RPM for different Spectre II exhaust systems.
| Identifier | ExFiles\Box 93\1\ scan0009 | |
| Date | 4th December 1934 | |
| S.P.3. SPECTRECodename for Phantom III II EXHAUST SYSTEMS. AEROLITE PISTONS. Hs{Lord Ernest Hives - Chair} 1536 CAMSHAFT. TIMING '090 C/LCE Hs.{Lord Ernest Hives - Chair} 1526 SYSTEM. IO 7° PTDC IC 53° PBDC EO TDC EC 48° BBDC ① OPEN EXHAUST (SHORT PIPES) ② MANIFOLD, DOWNTAKE PIPES, EXPANSION BOX & INTER PIPE. ③ MAIN SILENCER, FITTED WITHOUT TOP HATS & CENTRE TUBE. ④ As ③ WITH SWAN NECK. ⑤ COMPLETE SILENCER SYSTEM. BHP R.P.M. BACK PRESS. INS. Hg. NHK 4-12-34 | ||