OK.. here is the BTU's ,
Gasoline, 111,745 on the low side
and E85, 81,800
with this we see that the percentage LESS for the fuels is as follows with the lowside BTU for gasoline being the constant.
Ethanol 32% less BTU
E85 27% less BTU
now the laminar flame speed of ethanol are 42CM/s and gasoline at abotu 30-31 CM/s we'll use 30 as the base
this gives us a 29% faster burn rate for E85.
but we have to look at total volume of fuel to compare flame speed to time taken for complete combustion now.
we also are forgettign the lower flashpoint of gas which may also be a contributing factor.. as when placed under pressure, ignition points raise so there are ALOT of variables. so timing advance may also be required due to the flash point increasing with pressure. coruse i may just be confusing it with boiling point.
but another interesting fact, AUTOIGNITION or the temperature at which it will ignite itself, for E is 363 degrees farenheit, but gas is only 280 at atmospheric pressure.
Last edited by Boostinfamily; 11-20-2012 at 09:15 AM.