V-E-V Miscellany, May 1974, May 1974
Petrol Injection 38/250
Perhaps I may be allowed to correct a few minor errors appearing in your recently published letter from Mr. David Scott-Moncrieff.
The “White Ninety Mercedes” was, as Mr. Scott-Moncrieff recalls, a spectacular looking machine indeed, although, as he maintains, a little deficient in performance. It was purchased from Mr. Crowe conjointly by the late Osmond Raphael (not Rafael) and myself c. 1925 and extensively used by us over a period of some years, its subsequent fate, in the ownership of Buddy Blythe, was, however, previously unknown to me.
The next notable vehicle jointly purchased by Raphael and myself was, indeed, the 38/250 supercharged Mercedes.
Raphael was, in fact, a manufacturing optician, and, incidentally, a gifted violinist, but not a music publisher.
The 38/250 was acquired in London and carried the standard twin fixed-choke up-draught carburetters, the Roots-type supercharger, which pressurised the carburetter intakes, being engaged, at will, by full flooring of the accelerator pedal. The ensuing howl was most impressive and the power increment noticeable.
Displacement of the boost-pressure gauge connection from upstream to downstream of the very restrictive carburetter chokes, however, revealed a rather pathetic maximum manifold pressure of little more than 3 p.s.i., and here was, indeed, a case for port or cylinder fuel injection.
Most fortunately I was, at that time, with the SU Carburetter Co., then already in fullscale production of fuel-injection systems for aircraft and US Army Ordnance vehicles.
The replacement of the original carburetters by plain steel ducts and the fabrication of a new steel air manifold, housing six inlet-port directed injectors presented little difficulty; nor, indeed, did the replacement of the camshaft mounted radiator fan by an existing SU six-point injection pump.
The nett results were highly gratifying.
About this time, however, Raphael and myself embarked upon the reconstruction of the 22-litre Benz, now immaculately restored by its subsequent owner Eric Milner and today the property of Mr. J. V. Murcott.
This heroic machine we had conjointly owned for some years, and the 38/250 was disposed of, presumably to Mr. Tom Wheatcroft, but of this I have no knowledge having myself been abroad at the time of its sale.
There seems, however, little doubt that it now reposes in a Prague museum. If it is ever taken out for an airing I can only hope that the fuel-injection system continues to function impeccably.
Edgbaston John N. Morris