Ethanol free Premium vs 10% Ethanol Premium

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Staytite said:
Ethanol is CH3.CH2OH and thus contains inherent oxygen. It is well reported that Ethanol causes a "weakening"
of the stoichiometric ratio due to the inherent Oxygen.

Although Ethanol has an Octane rating of 113, it has a lower calorific value than the "normal" ingredients of petrol.

It is well reported that Ethanol gives a lower power "effect" when compared weight for weight or volume for volume
than the normal ingredients of petrol which causes lower miles per gallon and lower power. Scientific investigations
and anecdotal give a lower consumption of 3 to 9% miles per gallon.

Worntorn is discovering/proving the lower power effect for our particular interest in old Commandos. Thanks to him.
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That’s great info, thank you.

So basically E10 requires the same A/F ratio but it gets some of that air (oxygen) from the alcohol?
 
worntorn said:
I'll see if we have weather.
I won't be changing mainjets just to accomodate different gas when out on the road, however its worth investigating just for fun.

Glen
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Understood. But if the ethanol is all that's available, you will.
 
Glen, what is the configuration of the bike that you used for these tests?

And... a big fat hairy THANK YOU for this and the other contributions that you've made to our community recently.
 
Fast Eddie said:
That’s great info, thank you.

So basically E10 requires the same A/F ratio but it gets some of that air (oxygen) from the alcohol?
Click to expand...
Nope. More ethanol fuel is required to make the same power. And since a carburetor creates that ratio by volumes, a jet change is needed.
 
concours said:
Nope. More ethanol fuel is required to make the same power. And since a carburetor creates that ratio by volumes, a jet change is needed.
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Yes see that jet changes are required and agree.

But I’m not talking about the mixture that takes place in the carb, I’m talking about the A/F ratio that’s gets burnt by the engine.

However the oxygen gets into the engine (in the air or in the alcohol) it is still going to be detected as air by an A/F sensor I think.

So I do not believe that a different A/F ratio is required in that context. I think the jet change is required to CORRECT the A/F and put the A/F ratio back to where it should be to compensate for the oxygen in the alcohol?
 
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Ethanol free Premium vs 10% Ethanol Premium
 
Could you fit a set of temperature gauges and tell us if the temp changes at all between E10 (or as it seems E21) and ethanol free? :cool:
 
Fast Eddie said:
Yes but we’re not talking race fuel here!

The petrol companies use alcohol in order to reduce the other stuff, so you’re not getting any overall better calorific value.
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I found that my '06 Charger made better ETs with 10% ethanol rather than non-ethanol 91 octane premium. That was with fuel injection though. I tried 110 octane non-ethanol race fuel once and the car was a pig in the 60'. I could feel more power on top but the low end and midrange suffered severely.

Any alcohol will have less specific "caloric value" per volume but the stoichiometric A/F ratio for alcohol is much lower allowing more fuel to be burned thus higher power output.

E85 is not race fuel either, but guys have discovered that it will make much more HP over non alcohol "race fuel".
 
concours said:
View attachment 82522
Click to expand...
1.8 cu in 4 stroke making over 3 HP with methanol and 15% nitromethane. (glow fuel)

Static CR is 12.7:1. Gasoline would never allow such a high CR and power output on similar engines at the lower CR that would allow detonation free running with gasoline is < 2.5 HP.

( just another of my hot rodding hobbies)

 
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So, let me try asking the A/F ratio question this way…

My Dyno man likes to see carb bikes at around 13:1.

That is clearly a little richer than the optimal stoichiometric ratio of 14.7:1 but that’s just too close to the bone for safety according to my man.

Does E10 fuel require a different ratio ?

If so, what ?
 
Your dyno man needs to run a bike on E10, jet for the best power is, with a few extra sensors to check on engine and exhaust temps and then take that recorded AF ratio for E10 over his current 13:1. I suspect his new answer will be 12:1 .

I ran the digger on E10 for one tankful, hunting under load showed weak mixture, all gone with super unleaded that is likely E5.
 
From a practical standpoint, what does all this mean for a stock Commando? The Amals on my 850 MKII have had 260 mains forever. Does it make sense to up the mains to 270 or something when running E10? My dyno would be the Ass_In_The_Seat model.
 
maylar said:
From a practical standpoint, what does all this mean for a stock Commando? The Amals on my 850 MKII have had 260 mains forever. Does it make sense to up the mains to 270 or something when running E10? My dyno would be the Ass_In_The_Seat model.
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5% higher so 260 x .05 = 273 so 270 will cater.
 
Fast Eddie said:
So, let me try asking the A/F ratio question this way…

My Dyno man likes to see carb bikes at around 13:1.

That is clearly a little richer than the optimal stoichiometric ratio of 14.7:1 but that’s just too close to the bone for safety according to my man.

Does E10 fuel require a different ratio ?

If so, what ?
Click to expand...
It sounds to me like the OP had the ragged edge optimum A/F ratio for gasoline. Often the leaner condition brought about with E10 will increase power when the A/F ratio is a bit "fat" with gasoline.

13:1ish is the usual A/F ratio to shoot for as it has some cushion. A/F ratios above 13:1 give diminishing returns as far as power with greater risk of detonation if other factors stack up, ignition timing, higher CHT, etc. Even with EFI, around 13.3-13.5:1 is the usual target as at WOT the ECU does not adjust A/F ratios. 13.8:1 might be safe when a close rein is used on other factors but 14:1 or higher is getting way too close to the edge.

So yes a slightly bigger jet would show some power advantage with E10 in most cases,
 
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Fast Eddie said:
That’s great info, thank you.

So basically E10 requires the same A/F ratio but it gets some of that air (oxygen) from the alcohol?
Click to expand...
Incorrect. It requires slightly larger jets if the A/F is optimized for gasoline. In fact, if the A/F ratio is a bit rich for gasoline, E10 can show a slight power gain with the same jetting due to a leaner condition. Before E10 became common in Northern NY state I would see better performance with my charger when I used E10 that was prevelent in New Jersey where I raced.

The added oxygen will not offset the lower stoichiometric A/F ratio requirements. Methanol will also require larger jetting. The higher the percentage of alcohol, the larger the jetting required.
 
Think i'll stick with super unleaded E5 until this is banned probably some time in the next two weeks
 
maylar said:
Glen, what is the configuration of the bike that you used for these tests?

And... a big fat hairy THANK YOU for this and the other contributions that you've made to our community recently.
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This is a stock 850MK 3 with original Amals still in OK shape.
Mainjets are 260s , although I changed mainjets about 20 times during the exhaust power testing.
Norton had it right with 260s and the fluted peashooters for UK or Coastal NA elevations.
The bike went slower on test with 270s & this exhaust. That was with the Chevron Supreme ethanol free I normally run. Occasionally when out on tour we are stuck using gas with ethanol, so I wanted to see how it compares with the Chevron Supreme.

Glen
 
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Dan1950 said:
Incorrect. It requires slightly larger jets if the A/F is optimized for gasoline. In fact, if the A/F ratio is a bit rich for gasoline, E10 can show a slight power gain with the same jetting due to a leaner condition. Before E10 became common in Northern NY state I would see better performance with my charger when I used E10 that was prevelent in New Jersey where I raced.

The added oxygen will not offset the lower stoichiometric A/F ratio requirements. Methanol will also require larger jetting. The higher the percentage of alcohol, the larger the jetting required.
Click to expand...

What A/F ratio should one aim for when using E10 fuel?
 
All this discussion about the relative power output of E10 Vs non-ethanol premium has very little relevance unless you are shooting for a low ET timeslip in which case, the E10 will have a slight advantage. I will run E10 in my outdoor power equipment to save $$$$ on the ridiculously expensive non-ethanol premium The same would be true on my Commando if I made a fuel stop at a station that did not offer non-ethanol premium. The only significant drawback of E10 (as long as components are E10 compatible) is what happens when the (carbureted) equipment is left unused for weeks at a time. That is when the hygroscopic traits of alcohol do their dirty work absorbing moisture from the atmosphere. This is not a factor on modern (sealed system) EFI cars, and I assume motorcycles, as there is no route for atmospheric moisture to enter the system significantly.

I will always opt for non-ethanol premium if available for my Commando, but only near the end of the outdoor equipment use season do I opt for the expensive non-ethanol to prevent bad things happening over the off season.
 
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Fast Eddie said:
What A/F ratio should one aim for when using E10 fuel?
Click to expand...

Note that these are stoichiometric A/F ratios. One should never tune to the absolute value. Always leave at least 1 point for safety factor to prevent detonation under varying conditions.
Fuel​
Stoichiometric AFR​
Pure Gasoline
14.7:1​
10% Ethanol Gas
14.04:1​
15% Ethanol Gas
13.79:1​
E85
9.75:1​
Pure Ethanol
9:1​
Diesel
14.6:1*​
 
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