No, the main reason for the MPG loss is that pure ethanol stoichiometric air/fuel ratio is 8:1 and gasoline is 14:1. The O2's control that and dump a lot more ethanol in than they do gas.

 

Question: Does using E85 in a 2010 5.4 Flex motor increase horsepower? I thought I read somewhere that the 5.4 gets about 10 more horsepower on E85. Can't find the info now.

If so, what type of sensor is used to determine the fuel?

And last, if the engine has a knock sensor, (it must as I found a part number for one) does it help to run a higher octane fuel during the hot dry summer months? When I had carbed engines, I had to either retard the timing, or run bigger jets in my holley carb.

 

There is a sensor in the fuel system that determines the alcohol level of the fuel.

You are correct it does produce more hp on E85, but you will lose about 30% mpgs, there is a shorter oil change interval, and you are supposed to run a tank of "regular" gas every so often.

Almost forgot, there is a knock sensor and you are fine running 87 octane year round.

 

I am aware of that. But, if the knock sensor detects knock, does it not retard the timing to prevent the knock? Thus reducing horsepower? The reason for the questions is the towing of a trailer and complaints of lack of power up hills. I know that it's worse in hot and dry climates. Just trying to figure out ahead of time before I tow, if going to a higher octane or E85 in the summer months will keep the power up.

 

Yes, you will get more power towing with E85 in a FFV, but expect absolutely terrible gas mileage. Ford does publish separate 87 octane and E85 HP and TQ numbers for the 2010 5.4.

 

chester, vehicles built after 1985 have some degree of anti-alcohol corrosion built into the fuel systems. while running E85 in a non-FF engine isnt the smartest idea, your fuel system wont die all of a sudden. After a long time, you may have to replace a few seals however.

for vehicles built previous to 1985, even E10 wreaks havoc on rubber. my airplane is a 1964 model, and in the past year when my local aviation fuel supplier switched to E10 autogas, I've noticed my fuel hoses have deteriorated a lot. the seals in the bottom of the drain sumps have already gone out and my wings were leaking about a gallon of fuel over the course of a week.

 

I can't run 87 octane in my trucks...

 

Does the sensor in the fuel tank determine the percentage of alcohol content, or octane to adjust the timing, fuel curve, etc?

 

The facts? E85 is more expensive to run per mile than gasoline.

 

I believe it senses the alcohol percentage, and that's only to set a baseline for the fuel and timing curves. The knock sensor and O2's do the fine adjustments.

Not necessarily - it depends on the fuel mileage difference and cost per gallon difference. You can't generalize like that, everyone's situation is different. I'm speaking on your particular cost per mile - I'm not addressing the actual big picture cost to make the stuff.

 

Show me any place where the percent of cost difference between E85 and pump gas exceeds the percent lost in mileage... and then one can say not to generalize. There isn't AKAIK any place the difference in price is 20-30% less.

 

(hundredths rounded up)
Pump Gas is 14.7
E10 is 14.1
E85 is 9.86 assuming its 85%, because depending on time of year it can actually be E70.
Pure ethanol is about 9.

 

I can't run diesel in mine...???


According to something I read last year when I got my truck, there is some sort of sensor that measures the conductivity of the gas to determine the alcohol content.

Also in figuring costs/savings, don't forget to factor in the cost of more frequent oil changes.

I think that if gas gets up to around $4 to $5 per gallon again the price gap between regular and E85 will widen quite a bit. Until then I don't think it is worth it.

 

20 to 30% gas mileage loss is worst case. I've heard of some vehicles that only lose 7%. As I said, it's going to depend on your particular price difference AND your particular mileage loss. I've also heard of E85 at 75 cents less than gas.

Bottom line - crunch your OWN numbers.

 

They are not worst case, they are the average loss. Those losses are documented on the government's fuel economy pages. Factor in shorter oil change intervals and the picture looks even worse for E85. There will always be some guy who claims no mileage loss or hardly any at all, but any time you look at actual test data it appears contradicts them. If the government stopped giving the corn industry and cane industries its sugar tit protectionism from imported ethanol, there might be a better economical case for it.