Ahhh, yeah. That’s exactly what I was thinking.
:willy :willy :willy
Chip
Once again the Professor succeeded at thought transfer mind reading,
Ahhh, yeah. That’s exactly what I was thinking.
:willy :willy :willy
Chip
Again BMF that sounds about right too.
E85 (85% ethanol + 15% gasoline) is better than straight methanol or ethanol but not a whole lot better. The energy content of this fuel can also be easily calculated by looking at the fractions, thus-
((85/100)*(12,780)) + ((15/100)*(19,065)) = 13,723 BTU/lb
E85 is about +7.4% better energy density relative to straight ethanol but -28% lower energy density relative to straight gasoline.
Thus as BMF indicates above to develop the same horsepower with the E85 fuel, you need to supply +28% (about 30%) more fuel to the engine. This is why laypeople are always perplexed that their FlexFuel vehicle gas mileage "tanks" when they fill up with E85. The engine needs 30% more fuel to support the driver's gasoline performance levels.
Thanks Chip, it’s all in the math…….:biggrin
Thankfully a gt on ethanol E85 (NOT alcohol/Methanol) 30% more fuel is required over gas and WOT time 22-25 second for lets say a mile run. With 680lph pumps in the oem tank free flowing into that 3 gallon surge tank one should still have more than enough fuel to complete a mile run and I don't think anyone here would be looking to do anything over that.
Correct on the mileage. But if e85 is tuned properly per vehicle, it only cost .01$ per mile cost more than gas if the price of e85 is x % of dollars less than gasoline. You can run e85 at a much leaner Stoich than gasoline at cruising speeds due to its abilities to not detonate. There for you can make up for the extra use of the fuel by leaning it out.
Not that anyone in the car world cares because we use e85 for its ability to make huge Hp cheaper than race gas and its easy availability at local gas pumps.
Thanks for all the math!
How do you tune to account for unknown E85 blends? E85 can vary from 51% to 83% ethanol, depending on season and region.
How do you tune to account for unknown E85 blends? E85 can vary from 51% to 83% ethanol, depending on season and region.
Next I've been doing e85 in my cars since 2005. e50 will easily support 900whp. I personally on my GT have made 1370whp with winter blend e72 and e85 will support about 1700whp, on my GT i have made 1450. So just because we are seeing lower ethanol contents doesn't mean the fuel can't support some really good power. Its having the knowledge of the fuel and what its capable of.
I struggle a bit with the statements like, “e50 will easily support 900whp” and “e85 will support about 1700whp”. An engine can be designed to run on any number of fuels- gasoline, gasoline alcohol mix, alcohol, turpentine, kerosene, whiskey, etc. All the Indy cars run on straight methanol for safety reasons and those 2.2L V-6 engines make sufficient power with a very low energy density fuel to push those race cars easily over 200 MPH. The only thing the fuel supplies to the engine is chemical energy. The engine converts this chemical energy into mechanical work. Some fuels may provide more efficiency in the chemical-to-work process; some may produce fewer hydrocarbons or NOx byproducts, some lower combustion temperatures, some higher temperatures. Each fuel has its own niche. Designed correctly and fed with enough fuel (any fuel) an engine can produce a spectrum of different powers. The “fuel” does not determine the engine power output if the engine is provided with sufficient fuel quantities to allow the engine to achieve its internal mechanical design goals.
I stand corrected. The Indy Cars run 85% ethanol and 15% racing fuel. They make 575-675 hp depending on turbo boost. https://www.roadandtrack.com/motorsports/news/a7477/inside-indycar-engines-2014/