Turbocharging with no intercooler, petrol/ethanol

[J4nn3R]

Yes, there is lot of flexfuel cars, I know that. But most efficient ethanol engine is not flexfuel, it compromises too much. Compression ratio, ignition timing, boost pressure etc.. I don't know, could it even have smaller radiator? Of course lot of variables are ecu controlled, but I very much doubt that flexfuel engines very aggressively changes for example timing or boost pressure debending on fuels ethanol contet. They could, even should, thou?

Edit: What I mean, is that typical flexfuel engine is efficient when used petrol fuel and quite ok with ethanol. A pure ethanol flexfuel engine would be an engine, that is efficient with ethanol but petrol option could be some kind of "limb mode", that engine is able to run with it, but very ruined ignition timing and with very high f/a to avoid pinging. Do anybody get, what I'm thinking?

[cRiPpLe_rOoStEr]

Some folks in my country converted gasser cars to ethanol while turbocharging it back in the day, as it was a cheaper way to overcome knock. But I wouldn't advise anyone to get rid of an intercooler, even though bypassing it as as cold-start aid might be a reasonable approach.

[pgfpro]

Edit: What I mean, is that typical flexfuel engine is efficient when used petrol fuel and quite ok with ethanol. A pure ethanol flexfuel engine would be an engine, that is efficient with ethanol but petrol option could be some kind of "limb mode", that engine is able to run with it, but very ruined ignition timing and with very high f/a to avoid pinging. Do anybody get, what I'm thinking?

On my setup I have done the testing with E 100 Ethanol, E98 Ethanol, E85 Ethanol and GEM 38, GEM 40 and now testing GEM 47.

Low static compression ratios can be worked around by running Miller cycle (effectively Atkinson cycle + forced induction).

as Ecky posted above on my setup this is pretty much my engine type.
When I tested E100 Ethanol and petrol at light load Freeway testing, petrol always was a major winner when it came to FE. Now when it came to mid load the gains we're with Ethanol due to its knock resistance, but the Freeway amount of driving time was around 95% compared to the mid load needed.

So, it really comes down to you are trying to overcome Ethanol's numerically lowering heat value compared to Petrol. You can build an engine with high compression dynamic or static but in the end the heating values do matter.

These are just my opinion's so if you really want to build a engine that is for FE on Ethanol please do. Thinking out side of the box is always a great thing

https://afdc.energy.gov/files/u/publ...ison_chart.pdf

[J4nn3R]

Thanks everybody! There is great knowledge there, and absolutely great to hear what people have experienced.

As I wrote in start, right now I'm not going to build complete engine, but only changing to ethanol. Was thinking, if there is a way to overcome lower energy content. Well, there is no an easy way, if any way at all.

So, for now I'll stay n/a and try to avoid burning any oil based fuels, as they are mostly from our eastern neighbour which I don't want to fund for their latest acts. I'll burn happily local brewed booze made of side streams of food industry, even if my mpg dropd to somewhere around 30.

[freebeard]

I'd always thought of Vodka as tractor fuel made from potatoes.

[pgfpro]

Originally Posted by J4nn3R

Thanks everybody! There is great knowledge there, and absolutely great to hear what people have experienced.

As I wrote in start, right now I'm not going to build complete engine, but only changing to ethanol. Was thinking, if there is a way to overcome lower energy content. Well, there is no an easy way, if any way at all.

So, for now I'll stay n/a and try to avoid burning any oil based fuels, as they are mostly from our eastern neighbour which I don't want to fund for their latest acts. I'll burn happily local brewed booze made of side streams of food industry, even if my mpg dropd to somewhere around 30.

Oh that makes total sense. I wouldn't want to fund them also. I'm running mine on paint waste solvent and soon E98 made from distilled fruit.

[Piotrsko]

Alky is lower specific energy content than gasoline. You are comparing apples to pineapples. Convert gasoline mileage to the Alky equivalent (say 10% less), and beat that number.

If I ran monomethyl hydrazine and nitrogen tetraoxide, my mileage would be out of this world high, pun intended.

[cRiPpLe_rOoStEr]

Originally Posted by freebeard

I'd always thought of Vodka as tractor fuel made from potatoes.

As long as it has at least 80% alcohol by volume, it may burn. Otherwise it could still eventually be used as a supplemental water + alcohol injection