Recently I've seen recommendations to set ignition advance at 34 degrees, as against the factory figure of 38. This is said to be necessary because of the difference between modern fuel and what was available c. 1950. Given that advance allows the mixture time to burn, so the pressure peaks near TDC, this amounts to the claim that modern fuel burns more quickly.
I'm curious as to the basis for this idea. Do we have any petroleum engineers among us? What are the differences in composition and burn rate between
- the 72 octane "pool" petrol available in the UK postwar
- leaded gasoline sold from the 1960s until unleaded replaced it
- unleaded gasoline without ethanol
- unleaded gasoline with 10% ethanol
Cheers,
Dave
I'm curious as to the basis for this idea. Do we have any petroleum engineers among us? What are the differences in composition and burn rate between
- the 72 octane "pool" petrol available in the UK postwar
- leaded gasoline sold from the 1960s until unleaded replaced it
- unleaded gasoline without ethanol
- unleaded gasoline with 10% ethanol
Cheers,
Dave