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).
Engine performance characteristics including power output, detonations, and oil consumption.
| Identifier | ExFiles\Box 109\4\ scan0102 | |
| Date | 29th June 1939 | |
| -2- POWER. As shown on the attached curve (S.94) the maximum open exhaust power and MEP is 170 BHP at 3750 R.P.M. and 130 lbs/sq.in. MEP at 2000 R.P.M. respectively. With the Buick type of exhaust system and tail pipe to suit 30.G.VII, the maximum figures are 142 BHP at 3500 R.P.M. and 122 lbs/sq.in. MEP at 1750 R.P.M. These curves are without fan and air silencer, which collectively, would further reduce the silenced power down to 130 BHP at 3500 R.P.M. and 120 lbs/sq.in. MEP at 1750 R.P.M. The 30 BHP loss to the exhaust system at 3750 R.P.M. (16" Hg back pressure) compares with 25 BHP loss previously obtained on the actual Buick system off the Buick car. The difference, we consider, is in the tail pipe, the loss to this in the R.R.-Buick system being 14 BHP. DETONATIONS. Complete with the above exhaust system and Buick air silencer, and running on Redline which is a No.3 grade of fuel, there are slight detonations full throttle up to 1500 R.P.M. To be clear of these detonations by retarding the ignition advance, it is only necessary to lose 2 - 3 lbs/sq.in. MEP from the maximum figures, which, in view of the output and the grade of fuel, is very satisfactory. OIL CONSUMPTION & "BLOW BY". As specified the unit has a mixture of solid bores and short inserted cylinder liners together with standard tin-plated Aerolite pistons, and tin-plated rings (no L section ring). The consumption as checked at 4000 R.P.M. on Motorine C at an oil inlet temperature of 100°C - 35 lbs/sq.in. is reasonable, though not exceptionally good, the "blow by" figure, however, is very low and .5 cubic feet per minute. | ||