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Discussion Starter · #1 ·
In case anyone was curious about the Otto cycle, you can view in this link. Notice what happens just before BDC on the exhaust stroke. The exhaust valve begins to open and the gasses push there way out even before the exhaust stroke begins. Look how dangerously close the piston is in relation to the exhaust valve! Wouldn’t mind seeing this in a boosted application with different cam profiles.

 

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Wonder how long it would last with that acrylic cylinder. That is super cool
 

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Getting a ton of blow-by on the rings. Should have honed it before running.
Acrylic Cylinder and a Teflon Ring will require much honing..lol
Also, did you notice the size of the fuel droplets on the intake cycle. . . .

Large fuel droplets, especially with an engine having such a low compression ratio, means that engine would not deliver sufficient HP to move a CTS-V
into the 9-Second area..:giggle:
 
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In case anyone was curious about the Otto cycle, you can view in this link. Notice what happens just before BDC on the exhaust stroke / CORRECTED TO STATE "POWER STROKE". The exhaust valve begins to open and the gasses push there way out even before the exhaust stroke begins. Look how dangerously close the piston is in relation to the exhaust valve! Wouldn’t mind seeing this in a boosted application with different cam profiles.

That is considered to be the 'Blow Down' cycle.

This (the EVO) is considered to be a very important event.
Some even call this event the most important valve event!

With the LSA Engines, we spread / widen the LSA angle.

When you widen the LSA Angle you can either advance the
exhaust opening, or you can retard the Intake valve opening.

When you advance the exhaust lobes ECL, you will open
the exhaust valve earlier. However, if the 'Burn Angle' is
long due to either low static compression, or wrong fuel
as an example, you will be blowing pressure out of the
exhaust side of the engine 'Early' and the engine will be
inefficient.

This is one of the reasons that E85 works so well with
these engines. E85 burns quicker, thereby reducing
the burn angle (duration of burn) but it also burns quicker.

Cheers
 

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Discussion Starter · #8 ·
Ducky, thanks for clarifying and correcting. It was a test to get your attention (lol)! Just a few questions for my own digestion, please sir?

So with E85, because it burns quicker and more complete, and is less likely to pre-detonate, one could conclude that there is a mechanical advantage in that the upward traveling piston does not have to work as hard to push the unburned mixture (more “mass” than complete combustion gasses) out during the exhaust stroke? Thereby clearing the way for a fresh, new intake charge, right?

Secondly, please clarify: E85 burns faster, not hotter, correct? And to what effect does water-methanol have in relation to the above? Curious to know the delta in thermal energy between pump gas, and E85 in BTU’s. Homework assignment for later…

Did anyone notice the glowing ball when the engine was at throttle versus idle? This is why it is important to these engines to manage intake temperatures! Especially in the center banks of the V8.
 

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"There are all sorts of units of measure to quantify energy content; you can measure it in British Thermal Units, joules or even calories, just like you do food. A standard gallon of 93-octane gas contains about 114,500 BTU of energy, which is around 450 calories, or the energy equivalent of a double cheeseburger. A gallon of diesel runs about 129,500 BTU, and pure ethanol measures out to about 76,100 BTU. If you're wondering why these fuels -- which are all liquid hydrocarbons -- have different energy contents, you need only look at their relative densities. Diesel is the heaviest, followed by gasoline and then ethanol.

Where pure ethanol and E85 ethanol -- 85 percent ethanol, 81,800 BTU -- triumph is in octane rating. Ethanol has an octane rating of about 108.6, which is only 0.10 octane lower than the methanol once commonly used in racing circles. But that's pure ethanol, not E85. While mixing 85 percent 108-octane ethanol with 15 percent 93 octane would yield something in the 102 octane range, the fact is that most manufacturers mix it with 84 octane or lower. That yields a final fuel rating of between 96 and 98 octane."



The BTUs are less, which is why you need more e85 when compared to gas.
 

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I think the driving factor is the stoichiometric air/fuel ratio for ethanol is much lower, so more fuel is required to achieve complete combustion. This is what makes it feasible to use, because if it was the same ratio as gasoline it would provide much less energy per cycle.
 
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