Performance table comparing Brake Horsepower (B.HP) and Loss for various exhaust system configurations at 4,000 R.P.M.
| Identifier | ExFiles\Box 8\8\ 08-page46 | |
| Date | 22th June 1938 guessed | |
| 4,000 R.P.M. B.H.P. | LOSS. OPEN EXHAUST | 98.3 MANIFOLD ONLY | 96.4 | 1.9 MANIFOLD & FRONT EXP. BOX | 91.2 | 7.1 " " & INTER BOX | 89.7 | 8.6 " " " without top hats & REAR SILENCER | 87.4 | 10.9 " " " top hats 45 holes STD. REAR SILENCER | 84.0 | 14.3 COMPLETE WRAITH EXHAUST SYSTEM WITH 1½" TAIL PIPE | 74.0 | 24.3 " " " " " 1¾" TAIL PIPE | 80.5 | 17.8 STRAIGHT THRO' 2" PIPE FROM MANIFOLD -> TOTAL LENGTH 110" | 92.1 | 6.2 FRONT EXP. BOX & 2" PIPE - TOTAL LENGTH 110" | 89.5 | 8.8 STRAIGHT THRO' FRONT PIPE, INTER BOX & STD. REAR SILENCER | 90.6 | 7.7 AS ABOVE WITH 1½" TAIL PIPE | 79.1 | 19.2 " " " 1¾" TAIL PIPE | 86.2 | 12.1 | ||
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).