Effect of Ethanol on HP and Mileage

[gto_in_nc]

Well-stated, Oracle. Thank you!

[Mr_Draco]

...

*Scratches head*

For those that ain't well edumacated?

[gto_in_nc]

Originally Posted by Mr_Draco

...

*Scratches head*

For those that ain't well edumacated?

Ethanol has less chemical energy than gasoline but helps with oxygenation so gasoline burns more completely with a gas/alcohol blend, generally evening things out --especially with rich-running OEM tunes (which intentionally don't aim for complete combustion, preferring engine safety and unburned hydrocarbons over increased efficiency and oxides of nitrogen.)

Some forum members are reporting slight personal gains in fuel ecomony while others are reporting slight drops.

Make more sense?

[CamaroSpike23]

10% ethanol blend - helps clean the engine and its emissions
85% ethanol blend - possibility for more power but lower mpg

[DGthe3]

Let me know if I'm way out in left field on this:

Diesel burns very hot, gasoline burns hot, ethanol burns sorta hot. NOx requires high temperatures to form. In diesels, this is unavoidable. In gasoline engines, there is a NOx spike at the perfect stoich ratio. Traditionally, engines run rich to avoid this. Moderate amounts of cooler burning ethanol will offset the temperature enough to prevent excess NOx. This allows for less fuel to be used (since it no longer needs excess fuel).

Does this make sense to guys 'in the know'?

[knowitman]

Originally Posted by PoleCat2SSRS2010

Ethanol requires more fuel consumption always!

In an engine truly designed for ethanol and not gasoline, you can get about the same gas mileage. Even though ethanol contains less BTU/gallon, it's higher octane rating/activation energy allows for a higher compression which helps the engine run closer to it's thermodynamic ideal efficiency meaning that a lower percentage of energy is lost as heat.

[The_Stache]

Originally Posted by knowitman

In an engine truly designed for ethanol and not gasoline, you can get about the same gas mileage. Even though ethanol contains less BTU/gallon, it's higher octane rating/activation energy allows for a higher compression which helps the engine run closer to it's thermodynamic ideal efficiency meaning that a lower percentage of energy is lost as heat.

Exactly, the problem lies herein that there is no mass-commercially available vehicle designed to specifically run on e85.

(and running an e85 designed engine on gasoline is just as bad as running a gasoline designed engine on e85)

[CamaroSpike23]

Originally Posted by diarmadhi

Exactly, the problem lies herein that there is no mass-commercially available vehicle designed to specifically run on e85.

(and running an e85 designed engine on gasoline is just as bad as running a gasoline designed engine on e85)

I still say we should adopt Brazil's setup of 100% ethanol.... aka Gasohol

[zebra]

^^ i almost converted my explorer to do that

[RonC]

Originally Posted by diarmadhi

Exactly, the problem lies herein that there is no mass-commercially available vehicle designed to specifically run on e85.

(and running an e85 designed engine on gasoline is just as bad as running a gasoline designed engine on e85)

Some GM truck and car engines are designed to run on E85. Their computers are specifically setup to moniter the ethanol blend % in the tank and adjust the air fuel ratio required for that blend in the tank at the time. 100% gasoline AFR is set to 14.68 to 1 and 100% ethanol is 9.0 to 1 AFR. E85 is set at 9.7 AFR and 10% is 14.0 to 1 in the flex-fuel truck tuning. The 5.3L truck engines set up for flex-fuel use 36 lb per hour injectors vs. 24 lb per hour without FF. They have to flow much more fuel per hour to produce the same amount of energy (power) in the same length of time. Real world result; a truck that gets 15 mpg on gasoline gets about 11 mpg on E85. My real world results using 10% ethanol blend gets about .5 mpg less than 100% gasoline in my truck with it's computer optimized for best mileage with each fuel.

[knowitman]

Originally Posted by RonC

Some GM truck and car engines are designed to run on E85. Their computers are specifically setup to moniter the ethanol blend % in the tank and adjust the air fuel ratio required for that blend in the tank at the time. 100% gasoline AFR is set to 14.68 to 1 and 100% ethanol is 9.0 to 1 AFR. E85 is set at 9.7 AFR and 10% is 14.0 to 1 in the flex-fuel truck tuning. The 5.3L truck engines set up for flex-fuel use 36 lb per hour injectors vs. 24 lb per hour without FF. They have to flow much more fuel per hour to produce the same amount of energy (power) in the same length of time. Real world result; a truck that gets 15 mpg on gasoline gets about 11 mpg on E85. My real world results using 10% ethanol blend gets about .5 mpg less than 100% gasoline in my truck with it's computer optimized for best mileage with each fuel.

What diarmadhi is saying is that a car designed to run specifically on E85 will have a higher compression ratio allowing it to run as efficiently as it can. Trying to use gasoline in one of these engines will cause it to knock and ping.

[RonC]

Originally Posted by knowitman

What diarmadhi is saying is that a car designed to run specifically on E85 will have a higher compression ratio allowing it to run as efficiently as it can. Trying to use gasoline in one of these engines will cause it to knock and ping.

Yes, an engine designed for E85 or 100% ethanol would be set up a lot different and could make more HP efficiently. However, it still would cost more per mile using E85 than gasoline because of its lower BTU output with the prices we have today.

The answer to the OP's question is; "in theory using 10% ethanol mix does not have the energy output of gasoline so it should get less mileage", however any real world effect on HP and mileage could vary because of engine tuning, driving habits, etc. IMO. Just try it and see for yourself, it won't hurt it.

[DGthe3]

Originally Posted by kylepo

source? Now can that mid range be put in a regular GAS er?

can't remember where, but to answer your second question (I skiped it for some reason) it can be run with higher amounts of ethanol, but it is NOT recommended and probably reduces engine life.