Ethanol free Premium vs 10% Ethanol Premium

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worntorn

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I thought this worthy of a thread.

Clear result on Dyno Hill, the Ethanol fuel knocked 5 kmh off the hilltop speed. I ran it three times to be sure.
As always, I couldn't feel any seat of the pants difference.
The bike ran well on the 10% ethanol fuel, but it made substantially less power.
On the Ethanol free Chevron Supreme the bike will gradually accelerate right to the top of the hill.
With the PetroCan 10% ethanol the bike accelerates slightly on the less steep first part of the hill until the steep main part of the hill is encountered. At that point it could only hold the speed, there wasn't sufficient power for any acceleration.
To be absolutely certain that something else wasn't causing this, I switched back to the Chevron Supreme for a final run.
Full power and acceleration returned.
5 kmh equates to a loss of about 4 bhp or 10% of the total power normally available at 4200 rpm.

I have to think that fuel economy also suffers by 10% with the Ethanol fuel.

This makes the expensive Chevron Supreme not so expensive, not that we worry about that with these old bikes.

Glen
 
concours said:
Take those main jets up two sizes, re-test please.
Click to expand...
There is about 25% more power available with alcohol over gasoline. However, the alcohol requires about 40% more fuel. I would think that would equate to a 4% jet size increase for 10% ethanol as a starting point.

Guys in the Midwest are using E85 in carbureted cars on the drag strip with substantial horsepower gains.

Big drawback with alcohol is the water absorption.
 
Last edited:
concours said:
Take those main jets up two sizes, re-test please.
Click to expand...
I can't find it right now but an old Triumph doc says that for every 10% alcohol you need 10% bigger main jet (at least that's what I remember reading).

From here: http://amalcarb.co.uk/downloadfiles/amal/Mk1_Hints_and_Tips.pdf

ALCOHOL FUELS. When using alcohol fuels, the following new components are necessary. A metallic banjo, preferably double feed if not already fitted, float chamber 622/051, banjo bolt washer 13/163, needle jet 622/100, jet needle 622/099 or 928/099 according to type of carburetter, filter gauze 376/093B and banjo washer 14/175. The main jet must be increased for straight alcohol by approximately 150%. The final setting must be a question of trial and error according to the nature of the fuel being used.

When using alcohol fuels it is advisable to error on the rich side to avoid engine overheating.

​

 
Interesting. But realize that most fuel pumps here in BC/Canada are labelled as containing UP TO 10% ethanol. So you don't know what you actually get without doing further work, such as separating out ethanol from petroleum with standard techniques etc.. Its just an upper limit imposed by the regulators.
 
I chose the PetroCan for the test as their 94 Octane was recently analyzed and found to contain 21 percent Ethanol, in spite of the 10% max regulation.
Clearly PetroCan is happy to use lots of Ethanol to attain high Octane levels.


Glen
 
Here I sometimes get very good running Ethanol gas and others my bike runs like crap.... Same stations/pumps. They cook the stuff right across the bay, but you never know for sure what the precise mix and quality shall be from one load to the next.
I'm glad that I don't push the old thing hard any longer.... I'd just as soon go through my remaining years without opening up the gutty works of my Commando and running it hard increases the risk of that happening.... Bad enough she's starting to use some oil if you catch my meaning.
 
Dan1950 said:
There is about 25% more power available with alcohol over gasoline. However, the alcohol requires about 40% more fuel. I would think that would equate to a 4% jet size increase for 10% ethanol as a starting point.

Guys in the Midwest are using E85 in carbureted cars on the drag strip with substantial horsepower gains.

Big drawback with alcohol is the water absorption.
Click to expand...
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.
 
Great test Glen, it seems to support what was discussed in another thread recently in that there’s an approx 5% power loss.

A 5% power loss is not normally detectable on the road via the arse Dyno and requires measuring in some way (lap times, Dyno or Dyno hill).

It would indeed be very interesting to see if a main jet change helps, my gut feel is it won’t restore the 5kmh but it would be very interesting to see the outcome. Did it feel weak?
 
It felt normal until the steep midsection of the hill. At that point it felt sluggish, no rpm increase happening.
I'll test the gasoline for ethanol content tomorrow.

Glen
 
If the jetting is optimum for the alcohol level and ignition timing is appropriate, the engine should produce at least the same power as straight gasoline although, of course, would use more fuel to do so.

IOW, if you ride regularly and all the stations that are easily available have only E10, if you jet/time the engine for that, there should be no loss of performance. As far as range, well, that depends on your riding style. For me, my fastback tank holds sufficient fuel for me to want to physically stop for a break before it would be low on fuel regardless of the reduced MPG. A roadster tank might be a different deal! :)

FWIW, In the old days it was common to add a can of gas drier (alcohol) to vehicle fuel tanks to absorb any water. There is some thought that this practice caused initial problems with motorcycle fiberglass tanks and was one reason for the abandonment of FG tanks back in the day. I have no idea if that is true but in any case, nowadays you don't have to add alcohol; it's already there! ;)
 
Anybody see any difference in spark plug colour after the E10 stuff?
 
MexicoMike said:
If the jetting is optimum for the alcohol level and ignition timing is appropriate, the engine should produce at least the same power as straight gasoline although, of course, would use more fuel to do so.

IOW, if you ride regularly and all the stations that are easily available have only E10, if you jet/time the engine for that, there should be no loss of performance. As far as range, well, that depends on your riding style. For me, my fastback tank holds sufficient fuel for me to want to physically stop for a break before it would be low on fuel regardless of the reduced MPG. A roadster tank might be a different deal! :)

FWIW, In the old days it was common to add a can of gas drier (alcohol) to vehicle fuel tanks to absorb any water. There is some thought that this practice caused initial problems with motorcycle fiberglass tanks and was one reason for the abandonment of FG tanks back in the day. I have no idea if that is true but in any case, nowadays you don't have to add alcohol; it's already there! ;)
Click to expand...
Are you sure about that?

Mixture is set to achieve the optimum air / fuel ratio. Does E10 require a different air / fuel ratio than straight petrol?
 
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.
 
Yes, I was wondering that. If the E10 octane rating is identical to the non-ethanol fuel I'd been using previously.
 
"Mixture is set to achieve the optimum air / fuel ratio. Does E10 require a different air / fuel ratio than straight petrol?"

Yes. Since E10 produces less "power" per volume of fuel, the volume of fuel delivered has to be increased.

Easiest way to figure it out would be on a dyno - just adjust for max power, making appropriate timing changes as necessary.

Years ago we did exactly that with a Hemi drag motor and managed to make the same power as with premium gas.
 
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.
Click to expand...
Remember, much of what you'll find relates to modern computer controlled engines, which are designed to "fuel trim" to suit the fuel being used.
Old carburetted engines rely on US to trim the fuel volume as needed.
 
Forgot to add to my earlier post re the ratio---


"It is well reported that Ethanol causes a "weakening"
of the stoichiometric ratio due to the inherent Oxygen"


When we did the dyno test, we did not do ANY checking/testing of the actual ratio, we just increased jet size based on dyno power readings, increasing jet size until power maxed out and then dropped off with the next larger size. I seem to recall some timing adjustments as well but can't remember any specifics.
 
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