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Test report detailing settings for a 3-B-IV Supercharged Zenith 48V1-2 Carburetter.


Identifier  ExFiles\Box 122\1\  scan0214
Date  5th July 1935
  
To Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer}
c. to Hs {Lord Ernest Hives - Chair} /CTS. {C. Trot Salt - Carburation}

4034

Hs {Lord Ernest Hives - Chair} /GR. {George Ratcliffe} 8/KW.5.7.35.

3-B-IV Supercharged
Zenith Carburetter 48V1-2.

Further tests carried out to improve carburation.

The float chamber position was altered and fitted to the front. This gave a definite improvement to acceleration, especially at low speeds.

The stroke of the bypass valve was increased from almost nil to .125" approx. full throttle. This enabled a smaller high speed jet to be fitted, together with an economy jet.

Performance checked only on Ticknall Hill at 47 secs. c.c.

The final setting is as follows :-

Choke 36 m {Mr Moon / Mr Moore} /m.
Main Jet 185
Comp. Jet 165
Slow Run. 85
Capacity Tube No. 1.
Economy Jet 180
Ventilation 4 m {Mr Moon / Mr Moore} /m.
Seating 3 m {Mr Moon / Mr Moore} /m.
Pump 13 m {Mr Moon / Mr Moore} /m.
Spring 600 grms.
Jet 70
Leak Nil.

Consumption Tests :-

14.6 m.p.g./50 m.p.h./ 71 miles.

17.3 " / 40 " / 71 "
  
  
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).


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