New E10 Fuel

[Stere]

Bit confused though that ethanol is higher octane so some  increased engine efficiency also?

 

 

 

[Stubby]

1 minute ago, Stere said:

Bit confused though that ethanol is higher octane so some  increased engine efficiency also?

 

 

 

higher octane does not necessarily mean more efficient . You need a higher compression to get the best from it . In fact if you use " high octane " fuel in an engine that is not designed for it you can get a lesser efficiency than you would with a lower octane fuel . ( I read it somewhere )  🙂

[openspaceman]

3 hours ago, Stere said:

Bit confused though that ethanol is higher octane so some  increased engine efficiency also?

 

 

 

Octane rating is to do with  how the fuel resists premature auto ignition, this can cause damage as a flame front moving through all the mixture from the spark is smoother than simultaneous detonation . Higher octane fuels tend to have slightly less calories but this can be made up for by using a higher compression ratio. The pressure from which the gases expand tends to be a direct correlation  with thermodynamic efficiency. Engine designers have worked well to increase overall efficiency and manage high compression ratios as petrol octane rating decreased with the removal of tetra ethyl lead.

[Dan Maynard]

I don't see how moving from 5% to 10% ethanol would cause a drop of 10% in efficiency.

[Piston Skirt]

On 29/08/2021 at 10:42, Jamie Jones said:

So it is about selling more and getting more tax revenues🤔

By replacing 10% of imported (for some countries) oil with locally made ethanol it is a nice chance for a country to influence import/export balance too.
It’s quite a sum of money at that level.

[Piston Skirt]

15 hours ago, Dan Maynard said:

I don't see how moving from 5% to 10% ethanol would cause a drop of 10% in efficiency.

Just running ethanol fuel in a 2-stroke after it is set up for non-ethanol causes pretty much lean condition (partly because of the oxygen in ethanol)

To counteract this you need to richen the mixture (=dump more fuel volume) for the same conditions.

Those 5-10% typically are described as “up to” so it may be never exact.

[Wonky]

2 hours ago, Piston Skirt said:

Just running ethanol fuel in a 2-stroke after it is set up for non-ethanol causes pretty much lean condition (partly because of the oxygen in ethanol)

To counteract this you need to richen the mixture (=dump more fuel volume) for the same conditions.

Those 5-10% typically are described as “up to” so it may be never exact.

I'm not sure I follow your thinking, when in another thread. “Eddie@aspen” says you may need to. See below for quote. So I would have thought the reverse would be needed..or no adjustment.

anyhow look at what garden kit says..

 

 

[Stubby]

1 hour ago, Wonky said:

I'm not sure I follow your thinking, when in another thread. “Eddie@aspen” says you may need to. See below for quote. So I would have thought the reverse would be needed..or no adjustment.

anyhow look at what garden kit says..

 

 

Eddie is talking about Aspen which is an alkylate fuel . It has no ethanol in it at all .

[Piston Skirt]

1 hour ago, Wonky said:

I'm not sure I follow your thinking, when in another thread. “Eddie@aspen” says you may need to. See below for quote. So I would have thought the reverse would be needed..or no adjustment.

anyhow look at what garden kit says..

 

 

Aspen is another thing.

Jumping from regular petrol to aspen also requires carb readjustment due to different alkylate atomization properties alone.

And yes, after going for Aspen most often it acts like “too rich”, especially on the low end.

Anyway for alkylate there is no “linearity” when comparing to all those ethanol spoiled mixtures of unknown age.

And honestly and personally I find the alkylates to be the most reliable and steady quality fuels. Yes, they cost more, but there is barelly anything in the engine no matter how old it is.

Probably my only negative experience in lifr was an attempt to start some oldschool engine in -24C

[peatff]

15 hours ago, Piston Skirt said:

And yes, after going for Aspen most often it acts like “too rich”, especially on the low end.

I've found I have to open the L screw up 1/4 to 1/2 a turn making them richer and had to speed up the idle to compensate. That is on two Stihl saws and a Husqvarna.