BTU content E10/E85/Gas/Diesel

[SVOboy]

Anyone have a link on hand? I thought it was on the site but I haven't been able to find it. Thanks!

[omgwtfbyobbq]

From Google,

1 gal of gasoline=124,884btu
1 gal of No.2 diesel=138,874btu
1 gal E100=~77,000btu
1 gal of E85=84,460btu
1 gal of E10=~120,096btu

YMMV

[SVOboy]

Thanks! Why do I suck at search!

[Matt Timion]

Thanks! Why do I suck at search!

You suck at the internets. :p

[Ryland]

and bio-diesel appears to be around 130,000 btu per gallon, altho it varries slightly depending on the oil used, or so says "the internet"

[Silveredwings]

E10 is like taking a 4% hit...unless it's atleast 4% cheaper. :)

[DracoFelis]

E10 is like taking a 4% hit...unless it's atleast 4% cheaper. :)
But that's assuming that the FE is linear with BTUs.

However, some car's ECUs can adjust timing, to burn ethanol more efficiently. So, depending upon your vehicle, the lower FE might not be anywhere near as bad as the lower BTU's would imply...

[SVOboy]

Did you adjust your timing at all while running the straight E85?

[DracoFelis]

Did you adjust your timing at all while running the straight E85?
I never claimed I run E85 in my CRX. In fact, I don't run E85 in any of the family's vehicles, as I don't have any cars that are designed for it (and would therefore be concerned about ethanol's corrosive effects, when used in too high a concentration). However, a co-worker of mine has a flex-fuel van, and reports that his van's FE only goes down about 10%-15% on E85 (much less than the BTU difference would indicate).

NOTE: He can currently get E85 for around $0.90/gal cheaper then E10 (although he does have to drive about 15 miles out of his way, to get that E85 price). But even with the extra trip to fill up on "corn juice", and the lower FE of doing so, he still thinks he is saving a fair amount (and given the much lower price of E85, I think he is right).

As to my CRX, I'm still trying to figure out which fuel my car like's the best. Most of the stuff around here is E10, and so that's often what I use. But there is one station advertising "no ethanol" in their fuel i.e. presumably pure dino juice). However, when I last filled up at that station, both my power and my FE went down some (even though the higher BTUs of pure dino juice, should have resulted in a little more power and FE)! And when I later filled up with E10 (on the next tank full), the car's power picked up almost instantly.

So I'm really left "scratching my head" as to what fuel to use. And while it is clear that total BTUs/gal makes a difference in FE, it clearly isn't the only factor in FE. And in some cases, a lower BTU fuel might actually give you better FE in some engines (especially if the engine in question, is happier with the burn properties of the slightly lower BTU fuel).

[SVOboy]

I was talking to the clencher about the timing, sorry for not being more explicit!

Anyway, that is odd. I've never noticed a difference with any gas, anything in the tank, any change in intake, exhaust, nothing. Hell, I can't even tell the difference with MPFI besides the sound, but mehbe that's just because I never hit 2k rpms even, :p

[SVOboy]

Next time you should try adjusting your timing to cope with the much much higher octane of the E85, that could have been some of the problem with the running of the car.

[SVOboy]

Hopefully that's not the case, :p I guess on an NA motor is wouldn't be such a problem but a friend of mine dropped 12/16 valves on his engine last time he let that happen, :)

[SVOboy]

I still say advance the timing, :D, but that's just meeeeee.

[SVOboy]

Care to explain a little more in depth?

[maxc]

The heat of combustion will make the over all mixer expand at a higher rate. Like in the WW2 planes. They leaned out on take-off, advance the timing(your right) and Water injected. They went from about 2000 HP to 2500 HP on take off. It saved them fuel.

[Ted Hart]

From Google,

1 gal of gasoline=124,884btu
1 gal of No.2 diesel=138,874btu
1 gal E100=~77,000btu
1 gal of E85=84,460btu
1 gal of E10=~120,096btu

YMMV

Hi, OMG...!
Looking at the numbers : at 124.9K BTUs per gallon, Google does not agree with industry standards, they are "out of date"! The new standard is 117K BTUs per gallon! Something has changed! The gasoline? Hmmm....
At any rate, the energy content of the alcohol-based gasolines decreases as the % alcohol increases! And we're supposed to want this stuff? Picture this : Less energy = less MPG = more gallons used = saving a little on oil useage? There is something wrong with this (energy balance) picture! Will someone please explain this?

[Ted Hart]

The heat of combustion will make the over all mixer expand at a higher rate. Like in the WW2 planes. They leaned out on take-off, advance the timing(your right) and Water injected. They went from about 2000 HP to 2500 HP on take off. It saved them fuel.

Hi, maxc!
I spent a year in SouthEast Asia ... and watched as the F-105s would begin their take-off roll (loaded with heavy bomb loads!). As soon as the brakes were released ...at engine run-up ... the water injection was switched on, and the color and noise of the exhaust changed dramatically! More thrust, a "bluer" color (instead of orange), and a noticeable smoothing / quieting of the exhause noise (still very loud, just less ragged) were obtained. I saw this hundreds of times, day and night (the planes flew 24/7). The plane's water bladder was quite large (looked like 60 or 70 gallons), and took a full load at each refilling...with DI (demineralized) water. Fascinating!

[maxc]

Hi, maxc!
I spent a year in SouthEast Asia ... and watched as the F-105s would begin their take-off roll (loaded with heavy bomb loads!). As soon as the brakes were released ...at engine run-up ... the water injection was switched on, and the color and noise of the exhaust changed dramatically! More thrust, a "bluer" color (instead of orange), and a noticeable smoothing / quieting of the exhause noise (still very loud, just less ragged) were obtained. I saw this hundreds of times, day and night (the planes flew 24/7). The plane's water bladder was quite large (looked like 60 or 70 gallons), and took a full load at each refilling...with DI (demineralized) water. Fascinating!Cool, loved to see that!....... Just lost long reply......... Later more of what i'm working on.

[omgwtfbyobbq]

Hi, OMG...!
Looking at the numbers : at 124.9K BTUs per gallon, Google does not agree with industry standards, they are "out of date"! The new standard is 117K BTUs per gallon! Something has changed! The gasoline? Hmmm....
At any rate, the energy content of the alcohol-based gasolines decreases as the % alcohol increases! And we're supposed to want this stuff? Picture this : Less energy = less MPG = more gallons used = saving a little on oil useage? There is something wrong with this (energy balance) picture! Will someone please explain this?

Ah, yes. This must be back from the MTBE days, got it from onlineconversions dot com. Now that we're using ethanol for emissions, each gallon of gasoline is actually E(some really small percentage), the energy content also probably depends on summer and winter blends, and even which refinery/crude was used.
The whole idea with ethanol is that by "investing" certain fosil fuels in corn, and gaining some energy from the sun, then refining and distributing it, we get more energy in than out, or something. Unfortunately, we don't since from all accounts fossil fuels -> corn -> ethanol breaks even in terms of energy in ~= energy out. However, we do alter the percentage input for each kwh of liquif fuel such that we may be using more of the cheaper fossil fuels, although I'm not sure how expensive natural gas is per kwh, so we might even be wasting energy in the big picture. Remind me and I'll try to look into this, a crude approximation should be doable.

[red91sit]

Tempos are not flex-fuel, and officially I shouldn't run E85 in there at all. I haven't run it long term so who knows if/what would happen. In the short term nothing blew up or blew out. One thing I did notice is some erratic fuel gauge readings; at first it seemed they only occurred when I had strong concentrations of E85 in the tank, but recently I had an erratic reading when the tank was straight regular. Well it is a 14 year old car so it might just be happening due to age, or perhaps there was an incompatibility between ethanol and the materials in the sending unit. Time will tell.

Did you get shocked when exiting your car aswell? I ran pure E-85 through my car a few times this summer when it was a lot cheaper. I noticed with the mix I'd get a shock everyonce in a while, which was weird to happen in summer. I then switched to pure E-85 with no gas mixed in, and huge shocks! everytime I got out of the car I'd get a nasty static shock! I've read that Ethanol can loose it's electrons when it's being ran through pipes or hoses? something along those lines.

On a side note, I was changing fuel filters and spilled E-85 all over myself, didn't think much of it until all my skin soaked in it started to burn like it was sunburnt and being rubbed!!! I guess the Ethanol is highly hydroscopic! so if you get it on ya, wash it off and use some lotion!

Also, my car would hit a governor using Ethanol, something no one else has ever reported doing!

[JanGeo]

My guess is at high throttle the injectors could not keep up with demand, as they would have to pass- what was it, about 25% more fuel?- to match the BTU requirements of regular fuel.

Actually it's the air/Fuel ratio that has to be lower not the BTU content that is the problem so you may have been running too lean and having fuel ignition problems. Certain fuels can burn over a wide air to fuel ratio and some can not.

[JanGeo]

Nope it is because of the chemical makeup of the fuel and the amount of oxygen molecules that are needed for it to burn properly - Butane requires a lot more air but has a lower btu content. Methanol I think needs like 8 to 1 ratio or something low like that.