Quote:
Originally Posted by Chuck33079
Right, doesn't e85 usually result in a pretty substantial drop in mileage? It's about 30% less energy by volume than pump gas and that's why you need more volume than pump, right?
|
Yes. E85 has about 72% as much energy as an equivalent gallon of gasoline. E10 should have about 96%.
Quote:
Originally Posted by POS VETT
In the case of my GM truck, the drop in fuel consumption is way less than 30%. The drop in energy content is also less than 30%. The number 30% or 33% is used to size up injectors and fuel pump to give them cushion so that they work in a smaller duty cycle.
E85 has a much higher knock resistance and it burns at a lower temperature, these two traits allow the engine to run at near stoichiometric (i.e. leaner) and at very advanced ignition timing for a more complete burn producing a better use of the fuel. When a PCM senses a knock with E10, it backs off timing and injects more fuel to combat its destructive effects, meaning power output is lower and fuel consumption is higher, then the driver uses more throttle to compensate which makes the fuel consumption of E10 is now much closer to that of E85, or possibly, even less.
|
The drop in energy content is very close to 30%. E85 is absolutely better for power, particularly in boosted applications, due to what you pointed out. That said you are just not going to get better or even close to the gas mileage you'll get on regular gasoline or E10.
http://www.edmunds.com/fuel-economy/...ison-test.html
https://en.wikipedia.org/wiki/Gasoli...lon_equivalent