BoB Spitfire 100 Octane fuel

[Skoshi Tiger]

Good point Raaid.

There is nothing in the 100 Octane fuel that produces extra Horse Power, but it does allows the engine to run in the conditions where the motor can produce more HP. (if that makes sense????)

For example, my valiant with it's 10:1 compression needs 98 octane petrol to run smoothly in all conditions. if I run it on standard unleaded (91 octane) it will ping and knock at even low RPM and is unpleasant to drive at any speed. Using 95 octane I can drive at regular city road conditions, but will get pinging only when I try to flog it!

For true motoring bliss I need the 98 octane fuel to use the entire range of RPM and power in my engine.

AFAICMO, the modifications performed to the Merlin to realise the benefits of 100 octane fuel were in the delivery system to allow the engine to run at the higher boost. The changes to the actual engine were minimal and more for reliability rather than increased power.

Cheers!

[WTE_Galway]

The advantages of the massive stockpile of 100 Octane the British built up before and through the war should not be underestimated.

As an example, the DB605 in Luftwaffe service produced 1450 hp with B4 (87 Octane) and needed Mw50 to achieve more power. The same DB605 running 100 Octane with the Swedish air force produced 1700 hp without needing MW50.

Of course with 100 Octane MW50 would not have have had near as much effect as it is basically an anti-knock agent.