Running a car on ethanol?

[Jonnycoupe]

E85 is RON105

Whats that in MJ/kg then? Cos the calorific value of petrol and diesel is that.

Octane has nothing to do with energy value, just an indication of what you exploit from it.

 

[Simon]

Any Power gains that are made with etahnol engines will be due to the higher octane allowing more ignition advance. Thinking of adding it to an engine thats not mapped for it won't make any gains.

Ethanol contains Oxygen (Carbohydrate based) rather than gasoline which is hydrocarbon, it also needs more to maintain a stoichiometric mixture. An engine on E85 need a air:fuel mixture of around 9:1 rather than 14.5:1 when using 100% Gasoline. So you need approx 50% more.

For specific fuel energy content: Ethanol is around 32MJ/kg vs 45-46MJ/kg of gasoline, hence you get about 50% less power out of the same amount of fuel, thus the reduction in fuel economy, as well as requirements for bigger capacity fueling systems.

So in balance, you get the same power (slightly more due to octane allowing more ignition) whilst using similar quantities of fuel. Engine hardware will need changing when going to higher levels of Ethanol as it starts to cause issues with seals and also valve seats.

Most OEMs only recommend a maxiumum of 10% Ethanol in normal gasoline. Most European 95RON unleaded fuels are around 5%. The major's super unleaded fuels are all 'proper' gasoline, Tesco being the exception whos supplier just uses the Ethanol as an octane booster.

 

[Dogbreath]

For specific fuel energy content: Ethanol is around 32MJ/kg vs 45-46MJ/kg of gasoline, hence you get about 50% less power out of the same amount of fuel,

50% less would be half, I make that about 30% less

 

[Simon]

50% less would be half, I make that about 30% less

I was thinking of the 50% theme, I meant to say gasoline has 50% more energy. Cheers for clearing up any confusion though

 

[Lumeycom]

50% less would be half, I make that about 30% less

Its not linear though....

 

[Simon]

Its not linear though....

Explain further.

Last time I checked a number was purely that, a number

 

[jigger]

Ethanol AKA ethyl alcohol, AKA moon shine ?

Funny cars have been run on this for years so it must have some serious performance gains over petrol.

 

[Lumeycom]

Explain further.

Last time I checked a number was purely that, a number

I'm trying to find the info but am failing so far..

best way i can describe it is like the decibel scale.. as in 130db is not twice as loud as 65db.

meh.. i'll keep looking

 

[Simon]

I'm trying to find the info but am failing so far..

best way i can describe it is like the decibel scale.. as in 130db is not twice as loud as 65db.

meh.. i'll keep looking

There is no log scale.

Energy content is how much energy 1kg of fuel provides when burnt.

It does vary on the efficiency of combustion when it is in an engine.

 

[Simon]

Ethanol AKA ethyl alcohol, AKA moon shine ?

Funny cars have been run on this for years so it must have some serious performance gains over petrol.

These engines are built completely different to a road car.

Dont think that because drag cars run on ethanol then adding a bit to the tank of an ST220 is going to turn it into a race car.

 

[Reality Bites]

These engines are built completely different to a road car.

Dont think that because drag cars run on ethanol then adding a bit to the tank of an ST220 is going to turn it into a race car.

not a race car, but would give it performance gains?

 

[jigger]

But if you did turn your st220 into a racing car your fuel would have a huge impact on what power output was attainable. And I think that is what OP is after.

Methanol would be worth looking into as a fuel additive, it should give more energy compared to alcohol.

 

[jigger]

not a race car, but would give it performance gains?

It would.. well should, it depend on the car the fuel was used in.

 

[Fr0dders]

dont top fuel dragsters use a fuel that mostly ethanol based.

 

[Simon]

not a race car, but would give it performance gains?

No, for the reasons already stated! You are not changing anything to accomodate the higher octane, so there is no point. Infact you are actually reducing the amout of energy in your fuel by adding Ethanol.

I thought that would have been obvious from my post?

 

[Simon]

Methanol would be worth looking into as a fuel additive, it should give more energy compared to alcohol.

Still less than petrol and the rubber fuel system seals would soon perish.

 

[Reality Bites]

No, for the reasons already stated! You are not changing anything to accomodate the higher octane, so there is no point. Infact you are actually reducing the amout of energy in your fuel by adding Ethanol.

I thought that would have been obvious from my post?

and i did ask if i needed any mods to accomodate it......so if i do, what would they be. If i can't get them for this particular car then the thread is finished for me.

 

[jigger]

If the car in question uses rubber seals. Silicone seals and fuel lines would solve any problems.

The advantages of both fuels is (I think) you dont need as much o2 to burn methanol compared to petrol. This has huge advantages as one of the main problems in running a engine is metering enough air.

Petrol per amount, has more -potential- energy but needs a lot of air.

 

[jigger]

dont top fuel dragsters use a fuel that mostly ethanol based.

I'm almost sure its a 100% ethanol.

It go's like this, with petrol car making the least power. I think top fuel cars are run on Nitro.

Petrol

Ethanol

Methanol

Nitromethane

 

[Dogbreath]

and i did ask if i needed any mods to accomodate it......so if i do, what would they be. If i can't get them for this particular car then the thread is finished for me.

The answers are in the thread if you read it!

If you want to use something like E85 you need to get the car remapped, and may need larger injectors since they will be flowing quite a bit more fuel. To take advantage of the higher octane the compression ratio needs to be raised, obviously this means you can no longer safely run on standard unleaded. You will also need to check that all parts of the fuel system are compatible with ethanol based fuels.

Not a trival or cheap exercise.