$ per mile: high compression/high test vs. low compression/regular

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For one thing, their cost of production of ethanol is significantly lower than the cost of US corn based ethanol - - - - - -

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I think that Venezuela subsidizes gasoline. It's nothing like "net production cost."

It's an economics trick -- screw your people in one way so they think they're being benefitted another way.

See "politics."

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so let's cut to the chase...

your entire argument for ethanol hinges solely on the premise that an ethanol/air mix is more compressible. but according to this:

f1 eng "Changing the cam will indeed change the actual compression"

is full of it and has simply been wasting electrons. i'm just surprised you didn't have more to say about brake hose "flaps" and galvanic potentials of metal dvm probes.

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...aaahhh . No, alcohol is a better RACING fuel because it produces more horsepower. It does that in three ways:

1) A cylinder full of ethanol-air, uncompressed and with the piston at bottom-dead-center, contains 9% more energy than a cylinder full of gasoline-air. 2) Ethanol has an octane equivalent of 115 and thus allows higher compression, which increases thermodynamic efficiency and thus produces more power. 3) Alcohol has a higher latent heat of vaporization than gasoline, which results in a cooler, denser charge in the cylinder, further increasing the amount of fuel-air in the cylinder and producing a slight supercharging effect as a result. The consequence is more horsepower.

Read the next paragraph in your link:

"Ethanol and methanol can take significantly higher compression ratios than gasoline. Racing engines burning methanol and ethanol fuel often incorporate a CR of 14.5-16:1."

What do you make of that, in contrast to what you're saying?

Why do you think F1 engines can run at a nominal ratio of 17:1 on gasoline? Do you understand enough about engine dynamics to know what's going on at 18,000 rpm? I don't mean to be snarky here, but if you read the previous few paragraphs in your link, and then the paragaph I quoted, you should have a clue that something is different up in that rpm realm.

The fact is that flame-front velocity is low enough that an engine running 18,000 rpm with optimal spark timing has not reached peak cylinder pressure until well after top-dead-center (TDC). So an engine running that fast can run a higher compression ratio without knocking. There's more to it, but that's the basic idea.

This gets into some of the higher issues in engine dynamics and is 'way beyond what we can discuss here. It also has progressed well beyond my knowledge, which tends to lag the world in general ,

Finally, one more time: a cylinder full of gasoline-air does NOT have a higher calorie content than the same cylinder full of ethanol-air. In fact, it has about 9% less. You seem to have trouble grasping this. It's because there is MORE alcohol in that cylinder, to re-state it for the tenth time.

He's right, it can make a significant change. In fact, getting more fuel-air into the cylinder, and thus increasing the "actual" compression, is the entire reason for racing cams.

That is, if by "actual compression" he means effective compression -- the multiple of atmospheric pressure obtained in the cylinder head with the piston at TDC on the compression stroke.

There are few things in this world that interest me less. Maybe crocheting is a little lower.

On the other hand, as an old club-level sports car racer, making more horsepower still gets my adrenelin pumping fast. d8-)

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It looks like their net/wholesale cost of producing gasoline and diesel fuels is also a tenth as spendy as anything we can accomplish.

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I don't believe that's and accurate analogy.

Venezuelans are not being screwed, unless a good dose of artificial inflation is something they badly need.

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Quite likely a lot less tax, and a lot less environmental red tape - and quite possibly easier drilling conditions, combined with a lower wage scale????

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Gasoline is a fungible commodity, the value of which is determined by international market prices. When a country produces gasoline and charges its citizens less than the world market price for it, that country is depriving its citizens of income it would otherwise derive, effectively tax-shifting to reduce costs for consumption while requiring other sources (other taxes) for general revenue.

Every country that subsidizes fuel this way is screwing its citizens in one way in order to give a benefit in another way. Since lower gas prices can make a government more popular, while reduced revenues is an abstract idea that doesn't translate directly to political advantage, despots and autocrats favor such subsidized gas prices.

Jim, it's clear that you're blustering about things you really know very little about.

Everything we've discussed here is basic automotive engine engineering and has been well understood for years. I'm going to give you a couple of links to further your education:

"Investigation of Knock limited Compression Ratio of Ethanol Gasoline Blends" James P. Szybist, Adam Youngquist, and Robert M. Wagner Oak Ridge National Laboratory Wayne Moore, Matt Foster, and Keith Confer Delphi Corporation

"It was found that at substantially similar engine conditions, increasing the ethanol content of the fuel results in higher engine efficiency and higher engine power. These results can be partially attributed to a charge cooling effect and a higher heating value of a stoichiometric mixture for ethanol blends (per unit mass of air). Additional thermodynamic effects on the ratio of specific heats (..) and a mole multiplier are also explored.

"It was also found that high CR can increase the efficiency of ethanol fuel blends, and as a result, the fuel economy penalty associated with the lower energy content of E85 can be reduced by about twenty percent. Such operation necessitates that the engine be operated in a de-rated manner for gasoline, which is knock-prone at these high CR, in order to maintain compatibility. By using early and late intake valve closing strategies, good efficiency is maintained with gasoline, but peak power is about 33% lower than with E85."

Then you can look at a few hundred SAE papers on the same subject:

When you're done, come on back and we can discuss this intelligently. Oh...don't miss your study of stratified charge (direct injection) combustion in high-rpm engines, such as F1 engines.

As it is, you're a phony and a troll. But you can improve your status in life.

translation: "i couldn't find that formula online and i didn't study thermodynamics at school so i haven't the slightest clue how to derive that formula for myself."

don't try to blow smoke up my ass ed. i told you right at the beginning of this thread that "conventional" compression ratio thinking was out the window thanks to the japanese and their research on combustion chamber design. but here you are not only unable to grasp the cold hard facts that 1950's "you can't use more than 8:1 without super ultra gasoline" is complete bullshit. the japanese routinely produce road vehicles that can run regular gas at 11:1 or greater. f1 apparently uses 17:1. all while you're clutching at ethanol industry propaganda straws and trying to deny reality.

the difference between us ed, is that i've actually tried to do that. i went to school to do that. you apparently got stuck at remedial math and never graduated from anything other than "bluster passes for muster".

Read the paper, Jim. Then go lick your wounds.

If you want to try redeeming yourself, tell us how "efficiency = T1 - T2 / T1" would be measured in an actual automobile engine. That's Carnot efficiency, a theoretical measure.

Go ahead. Give it a try. Then tell us how that relates to the bullshit you were slinging about temperatures.

ed, your reading comprehension doesn't do your old high school teachers any credit. when your cite says: "high CR can increase the efficiency of ethanol fuel blends", you apparently failed to understand the crucial fact that increasing compression ratio increases the efficiency of gasoline fuels too [which is of course why it's been researched at great expense and actually done by the japanese!].

your cite further goes on to say: "as a result, the ***fuel economy penalty*** associated with lower energy content of E85 can be reduced by about twenty percent". it doesn't say "eliminated" or "reversed", only "reduced". and do you remember how this conversation started off on the topic of energy content? no, i thought not.

[*** - my emphasis]

and theory dear ed is where you need to start. those that don't understand theory can't begin to understand practice. [oh, and combustion temps and exhaust temps are dead easy to measure actually.]

ed, do yourself a favor - until you can read for comprehension, do math, and figure out who you can bullshit and who you can't, you shouldn't just presume that everyone who doesn't lick your ass is blowing smoke - all it does is evidence your own predilections.

What it means in plain English is you get 20% more fuel efficiency than the energy content alone would predict. The predicted "fuel economy penalty" calculated based on energy content alone is somewhere between 25% and 30%.

You're going to fluster them, Jim, with all that arithmetic.

at least i won't be so flustered by reading comprehension issues that i start arguing with the wrong person!

I was actually just trying to explain why turbocharging works, and the relationship between displacement and power to a non-mechanically-inclined friend the other day. This might help (maybe not JB, but those in the audience who might be a little confused by this...) - think about it in terms of air, not fuel.

e.g. - use my car as an example. It has a displacement of just about 3 liters, meaning that in one cycle, or two crank revs (as it is an Otto cycle engine, but don't make me get into that) is can theoretically at

100% VE move 3 liters of air through the engine naturally aspirated.

OK, so our fuel has a theoretical maximum amount of energy per unit volume, and also a stoichiometric ratio with air at STP. So there is a limit to how much energy can be released per that three liters of air. Yes, the engine itself is inefficient and does not 100% convert that energy to work at the crank, but still. At this point the ICE is fairly well developed so increases in efficiency are happening, but incrementally, and there's fundamental limits there as well. (e.g. Carnot cycle)

So...

how do we make more power? Well, as power is RPM related, we could spin the engine faster. Or we could trick it into thinking it is a bigger engine than it is (this was why this came up in the first place, e.g. assuming an adequate intercooler to keep charge temps close to ambient, a 3 liter engine running with an intake pressure of 2 ATM absolute thinks it's more like a 6 liter engine. Which is, of course, lots of fun.) OR - and Ed, I'm sure that this is the point you were making, you could use a different fuel. Alcohol, for example, carries less energy per unit volume as a liquid - which is why, taken, on a MPG basis, alcohol is a lousy motor fuel - BUT when you take the ratios of combustion into account, it actually is a very good fuel for racing, you just burn a lot more of it.

here's a pretty accurate yet not too technical explanation that I found after a quick web search:

if you look at their simplistic numbers, you can see that with the same engine, you will burn about twice as much alcohol as you will gasoline at WOT at a given RPM - *BUT YOU WILL MAKE MORE POWER!* due to the higher energy content of alcohol *per unit air used.*

This also neglects the cooling effects of alcohol on the intake charge as well (assuming a non-DI engine) and higher octane ratio than gasoline which allows the engine to be designed for greater efficiency than gasoline.

So, in short, whether alcohol or gasoline is a better fuel depends on your criteria. For racing in a class or series where fuel consumption by volume is not an important factor, alcohol kicks gasoline's butt hands down, because the main consideration (at least as far as the engine is concerned) is simply making the most power possible from the lightest engine possible. For street driving, where your primary concern is likely cost per unit energy, with cost per unit volume being a secondary consideration (for cruising range), gasoline still wins, as alcohol typically has a cost per unit volume ranging from slightly more than gasoline up to $100 a liter or more for some highly specialized alcohols (that might only be 50% or less alcohol by volume! ) and both methanol and ethanol (the two alcohols most commonly used as motor fuels) do in fact carry less energy per unit volume.

nate

That's a good, clear explanation, Nate. Maybe that will help anyone who has tried to follow JB and me about the barn.

Actually, JB probably recognizes all of this. He's a smart guy. But anyone who has followed his antics knows that he just can't admit when he's made a mistake. Instead, he takes off on a trip into the "Baffle Them With Bullshit" zone, increasing velocity until he puffs up his chest, cites his college degrees (problematic) and waxes ecstatic about "Japanese research" or the brilliance of the pushrod engine-tuners in North Carolina.

I think he's about crapped out on it now, and things will settle down.

If there is anything you have shown a knack for, "arguing with the wrong person" would be it

Thanks Ed but on a reread I totally horked the last paragraph... should read "For street driving, where your primary concern is likely cost per unit energy, with energy per unit volume being a secondary consideration" - brain/finger interface is apparently not perfected yet.

nate