Ethanol free Premium vs 10% Ethanol Premium

An interesting suggestion. If 2 degrees made a difference, could that be affect starting (keen to avoid any chance of backfiring for a mk3 electric starter / sprag bearing)?

Have you noticed any difference in the way the bikes ride on the way to the test runs, such as uneven running, any spitting?

Enjoying following the tests.

"If 2 degrees made a difference, could that be affect starting (keen to avoid any chance of backfiring for a mk3 electric starter / sprag bearing)?"

That's a good question...

I tend to think that it would not adversely affect starting because the same burn characteristics that would "allow" more advance and power at max would also allow more at starter speeds without kickback. BUT, I certainly don't know that for sure.

Obviously that's one advantage to either a programmable EI or a conventional distributer (which can be "tuned" for a specific curve with different weights/springs).

Although I’ve never tried it to compensate for alcohol, whenever I’ve tried playing with ign timing 2-3 degrees either side of nominal on the dyno, it’s made bugger all difference!

I’m only talking about old Brit bikes here though I imagine it’s a different ball game with modern engines.

worntorn said:

I've been using this hill as a tuning dyno for a long time with hundreds of runs on various old bikes. I have the tuned speed for each bike recorded in its log book.
The greatest variation from the norm has been 1 kmhr with same bike, same fuel, same tune.
The runs are all in temps 55-70f.
1 kmh equates to about .8 bhp, so I don't worry about weather, humidity, barometer other than no runs in very cold or very hot weather.

Glen

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While ambient temperatures are one of the most significant factors, barometric pressure is also just as or perhaps more significant. After all, it is atmospheric pressure that pushes the air/fuel charge into the intake port/combustion chamber.

Mart UK said:

An interesting suggestion. If 2 degrees made a difference, could that be affect starting (keen to avoid any chance of backfiring for a mk3 electric starter / sprag bearing)?

Have you noticed any difference in the way the bikes ride on the way to the test runs, such as uneven running, any spitting?

Enjoying following the tests.

Click to expand...

I can't feel any difference in running with any of the fuels, other than less power on the hill with ethanol. The bike is starting easily and running smoothly with a steady idle on all of the fuels.




Glen

Dan1950 said:

While ambient temperatures are one of the most significant factors, barometric pressure is also just as or perhaps more significant. After all, it is atmospheric pressure that pushes the air/fuel charge into the intake port/combustion chamber.

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The initial 7% ethanol vs ethanol free Chevron runs were done same day, 20 minutes apart.

In any case, running as I have done on fine mild days only shows the tiny variation of 1 kmh unless tuning changes are made.
That is over many years, many runs.

I'm getting a lot less variation run to run than my friend who is hiring a dyno for tuning. They had a 9% improvement in dyno results 2 weeks apart, no change in the bike.
These were supposed to be corrected dyno numbers, in other words weather change effects negated.
After much discussion the Dyno operator admitted to a recalibration of the Dyno because " Customers didn't like the low numbers we were getting"

The hill is always the same, it doesn't ever recalibrate.

The worst result for this bike was 96 kmh with a quiet Interstate exhaust system. Black Caps were almost as bad.
The best result so far is the 117 clocked yesterday on the Coop pure gas.
Getting really close to the 120 kmh goal.


Glen

worntorn said:

Next I went down to the nearby Coop gas station with five 20 litre Jerry cans.
I had read on a forum that Coop does not put any ethanol in their fuel, they just put the " Up to 10% ethanol" label on the pumps to satisfy Government regs and keep the Greenies at bay.

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Do worry too much there all in Glasgow

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.

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Yes and the compression has to be bumped up a lot to take advantage of ethanol's properties. Not something you can do at the drop of a hat.

motorson said:

Yes and the compression has to be bumped up a lot to take advantage of ethanol's properties. Not something you can do at the drop of a hat.

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Advancing the ignition timing significantly will take some advantage of the alcohol fuel.

Amal has some info on alcohol, among other things, in these two articles.:

http://amalcarb.co.uk/downloadfiles/amal/Mk1_Hints_and_Tips.pdf
http://amalcarb.co.uk/ethanol-fuels