ethanol free fuel

[dave999]

Doesn't higher Octane give more power but burns hotter, causing more risk of pre-detonation and possibly seizing ?

I tend to use the lower Octane and have had no fuel related issues.

octane rating is linked to the ability of the fuel to burn with a clean flame front, it has an impact on how fast or slow it burns.

low octane fuel tends to be slightly more explosive, burns in a quicker and less controlled way and will ignite by itself at a lower level of compression than higher octane fuel
high octane fuel burns slower and in a more controlled way, its harder to ignite and is less likely to just "go off bang" when compressed
you use the higher octane fuel in a motor set up with a higher CR and a more aggressive timing curve. i.e. a more efficient motor
race fuel is often 100+ RON avgas can be higher propane is sometimes 105 +

so if your motor is happy with 95 RON there is absolutely no point in buying 98 reap the benefits of cheaper fuel
the risk of detonation and seizing would increase with going lower on the octane rating not higher lower the octane and the fuel becomes more and more unstable
which is why so many standard indian motors have really quite low compression ratio, their fuel was in the past generally considered to be Lower octane than ours, i.e similar to most of europe after the war. these days not so much. they've got audis mercs and BMWs like everyone else

If you did buy 98 , it should make little or no difference, the slower burn would have marginal effect but ultimately the motor doesn't need the 98 RON.

it shouldn't make it run noticeably hotter unless your ignition system is marginal and you have flaming fuel mix blowing out the exhaust port into the U bend
(which is unlikely, you'd have many other problems before you got there)

the only time changing to a higher octane fuel, (without some engine changes to CR, porting or cam profile) gives a seat of the pants increase in power or torque is when you have a fuel injection ecu controlled engine that can learn, based on feedback from knock sensor, MAP and lambda sensor.
it will adjust its own timing, both ignition and cam timing in order to take advantage of a fuel that can put up with more abuse i.e be compressed more to maximise the power and torque or fuel economy (cam timing, open and close valves earlier or later to get more fuel mixture in ) and needs to be ignited earlier in the cycle, becasue it burns in a slower controlled way (more ignition advance for that RPM)

diesel thats the other way round, the best diesel has, using the wrong term, a really low octane rating. you need it to detonate as there are no spark plugs. it just get shoved into the cylinder at the right time and fingers crossed goes BANG

2 stroke diesel.....that might be fun but 50s truck engines don't fit lambrettas.

dave

[dave999]

stolen from here

https://www.autofuelstc.com/fuel_testing.phtml

its a US site hence references to Gas and potentially olives in bottles everyone knows they grow in jars with bits of chilli and garlic stuffed in em
the reference to not using the fuel is becasue this is a from a vintage aeroplane site and nobody wants their fuel system to become broken at 10000 feet


the water attracts the ethanol in the fuel to sit with it in the bottom of the tube
but water and ethanol/additives mix to a certain extent like salt dissolving in water so the distance above the line isn't exact ethanol will pack together with water
for example the same way you could hide a load of smarties in a full of eggs egg-box...only when you have jammed in a lot of smarties does it become apparent, most sit amongst, but some will make a visible break for freedom once it get overly full in there. ethanol and water fit together in a similar fashion

so the effect is more obvious with E10 or higher levels of ethanol

drop in food colouring if it helps.

you can of course pour off the de- ethanoled fuel but, you don't know what else you removed and you have just reduced its octane rating
which you could put right with an octane booster

but what a faff.....



HOW TO TEST FUEL
FOR ETHANOL
To determine if ethanol is in the gas:

On a test tube or olive bottle six or seven inches long, make a permanent line about two inches from the bottom.
Fill with water to this line, then fill the tube to the top with gasoline.
Cover the tube, agitate it, and let it stand.
The ethanol and water will mix and separate out together. If the water level appears to have increased, the fuel contains ethanol and should not be used . Ethanol percentages of less than 5% can sometimes give a reading below the line. Therefore, any deviation in the water line indicates the presence of ethanol and should serve as a basis for rejecting the fuel.

BP ultimate came out good....but that was probably 10 years ago.... as stated further back in this its potentially up to 5% now

dave