E10 petrol

[Billnick]

My local servo has E10 unleaded 94 octane for 104.9, that is 4 cents below 91 unleaded, plus 4 cents off if you buy more than 40 litres. With the man on tv telling me 'E10 has evolved' and being a little short on cash I thought I would try a tank to see for myself. Quite frankly I couldn't tell any difference. I reset the trip counter and got just as many km. I don't have a trip computer and I sail through a tank in about 4 days doing over 100km / day with my cleaning business. I'm on my second tank now to confirm my findings.

[Banshee]

I track all my km & fuel usage.
After I got it ~7 years ago, I ran on just E10, 95, 98 for at least a month each.

I found that I could get marginally more km on 95 or 98, but nowhere near enough to make it cost effective. My JK runs just as well on E10 & the milage is comparable. But the cost difference makes it MUCH cheaper to run E10.

[layback40]

As long as your fuel system components are able to cope with E10 its ok. Dont leave it sitting for months without use though, it goes off quick.

[Nanook]

You will use more E10 than standard Unleaded due to the fact it burns more readily than unleaded. However around town you won't notice much of a difference.

If you are doing a long trip with lots of highway miles then you will see a much larger difference especially when compared to 95.

There is nothing wrong with E10, however it can be nasty if you get water in your tank. Ethanol mixes readily with water and when it does it becomes acidic.

Fuel sitting in the tank leaves a varnish on the surface which does no harm at all. The trouble is, if your E10 mixes with water and does become acidic this can cause the coating to flake off which then can go through your system clogging injectors.

Don't let this stop you from using E10, but if you are going to use it, like any fuel you buy get it from a reputable servo that has a high turn over.

[Petehehe]

You will use more E10 than standard Unleaded due to the fact it burns more readily than unleaded. However around town you won't notice much of a difference.

If you are doing a long trip with lots of highway miles then you will see a much larger difference especially when compared to 95.

There is nothing wrong with E10, however it can be nasty if you get water in your tank. Ethanol mixes readily with water and when it does it becomes acidic.

Fuel sitting in the tank leaves a varnish on the surface which does no harm at all. The trouble is, if your E10 mixes with water and does become acidic this can cause the coating to flake off which then can go through your system clogging injectors.

Don't let this stop you from using E10, but if you are going to use it, like any fuel you buy get it from a reputable servo that has a high turn over.


Before I bought my JK I read somewhere that the JK equipped with the 3.6L Pentastar can run pretty happily on E10 as well as E85, so I've been buying E10 pretty much exclusively. I have noticed that around town and on the highway the fuel usage averages at about 10-15L /100km. However when I go offroad, particularly on the beach, fuel usage goes absolutely through the roof.. I reset my fuel usage tracker when I went on the beach just this last Saturday and it was at like 28L/100km.

Do you reckon I'd see better range if I used regular 91?

[Nanook]

I do most of my off roading on sand and to be honest, it won't matter what fuel you are using. Your engine works really hard on the beach trying to overcome the resistance that sand creates so you will chew through the juice.

Normally, I tend to use 91 or E10 around town or on the beach. Because you will use so much fuel on sand, I just use the cheapest possible.

If I'm going away on a long trip with the camper trailer I always fill with 95 or 98 as I find I get better economy.

[Banshee]

Before I bought my JK I read somewhere that the JK equipped with the 3.6L Pentastar can run pretty happily on E10 as well as E85, so I've been buying E10 pretty much exclusively. I have noticed that around town and on the highway the fuel usage averages at about 10-15L /100km. However when I go offroad, particularly on the beach, fuel usage goes absolutely through the roof.. I reset my fuel usage tracker when I went on the beach just this last Saturday and it was at like 28L/100km.

Do you reckon I'd see better range if I used regular 91?

No. That sounds pretty normal. It is the nature of offroading that you will use a lot more fuel per km.

When I was testing the types, I was doing daily 40km trips along the M4, so I was able to get consistant traffic.

You will use more E10 than standard Unleaded due to the fact it burns more readily than unleaded. However around town you won't notice much of a difference.

If you are doing a long trip with lots of highway miles then you will see a much larger difference especially when compared to 95.

There is nothing wrong with E10, however it can be nasty if you get water in your tank. Ethanol mixes readily with water and when it does it becomes acidic.

Fuel sitting in the tank leaves a varnish on the surface which does no harm at all. The trouble is, if your E10 mixes with water and does become acidic this can cause the coating to flake off which then can go through your system clogging injectors.

Don't let this stop you from using E10, but if you are going to use it, like any fuel you buy get it from a reputable servo that has a high turn over.


I don't get this. Ethanol + water is just an ethanol water mix. They do not chemically react together. Unless it means that it allows it to react with some of the additives in the fuel? (Otherwise you are taking a big risk drinking beer! E6.5! :p Wine, E10-15. Scotch, E45.)

If anything, I would be glad that the ethanol is miscible with both the fuel & water, since it means that if you get water in your fuel, it will get run through & out the exhaust. If you get water in straight petrol, it sits in the bottom of your tank & either rusts it out or until you get enough that it is picked up & you get straight water to the engine & it stops because you are getting water & air instead of fuel & air.

[MidnightMods]

Before I bought my JK I read somewhere that the JK equipped with the 3.6L Pentastar can run pretty happily on E10 as well as E85, so I've been buying E10 pretty much exclusively. I have noticed that around town and on the highway the fuel usage averages at about 10-15L /100km. However when I go offroad, particularly on the beach, fuel usage goes absolutely through the roof.. I reset my fuel usage tracker when I went on the beach just this last Saturday and it was at like 28L/100km.

Do you reckon I'd see better range if I used regular 91?

Completely incorrect it can run on E85, if a car can run on normal fuel and/Or E85, but must have a flexi fuel sensor and tuning required. Which the JK does not have. E10 is just shitty cheap fuel blended with some Ethanol to bump up the RON

[layback40]

I don't get this. Ethanol + water is just an ethanol water mix. They do not chemically react together. Unless it means that it allows it to react with some of the additives in the fuel? (Otherwise you are taking a big risk drinking beer! E6.5! :p Wine, E10-15. Scotch, E45.)

If anything, I would be glad that the ethanol is miscible with both the fuel & water, since it means that if you get water in your fuel, it will get run through & out the exhaust. If you get water in straight petrol, it sits in the bottom of your tank & either rusts it out or until you get enough that it is picked up & you get straight water to the engine & it stops because you are getting water & air instead of fuel & air.

Your chemistry is very simplistic. A year 12 student could explain to you about oxidation of ethanol. Stick an open bottle of white wine in the sun for a few days & try & drink it. That will teach you about the reactivity of ethanol.
Many rubber & plastic components are damaged by ethanol. The glue that holds the paper element together in fuel filters can be dissolved in high ethanol fuels.
If you get water in your fuel, it will remain as a second phase & draw some of the ethanol out of the fuel. This reduces the RON of the fuel.

Unless the fuel system is specifically designed for ethanol best avoid it.

[Nanook]

If anything, I would be glad that the ethanol is miscible with both the fuel & water, since it means that if you get water in your fuel, it will get run through & out the exhaust. If you get water in straight petrol, it sits in the bottom of your tank & either rusts it out or until you get enough that it is picked up & you get straight water to the engine & it stops because you are getting water & air instead of fuel & air.


The trouble is, ethanol is soluble in water due to hydrogen.

Water is heavier and will sink to the bottom of the tank. Ethanol tends to separate from fuel and sits between the fuel and water as a second layer. It then mixes with the water where it becomes a solvent. This then eats into the varnish coating the tank which can be picked up and sent through the whole fuel system.

This is why E10 is not for marine use.

I'm talking worse case scenario here but it can and does happen. If you have a high turn over of fuel, it's not much of an issue but if it isn't a daily driver like mine (Mine can sit for weeks without use as I have a Hilux dual cab work truck) then it can be a risk.

[Banshee]

Your chemistry is very simplistic. A year 12 student could explain to you about oxidation of ethanol. Stick an open bottle of white wine in the sun for a few days & try & drink it. That will teach you about the reactivity of ethanol.
Many rubber & plastic components are damaged by ethanol. The glue that holds the paper element together in fuel filters can be dissolved in high ethanol fuels.
If you get water in your fuel, it will remain as a second phase & draw some of the ethanol out of the fuel. This reduces the RON of the fuel.

Unless the fuel system is specifically designed for ethanol best avoid it.

Wine going off has nothing to do wioth ethanol/water. That's a reaction between oxygen & the other volatiles in the wine. You'll get the same reacion in low/no alcohol wine.

I admit my chimstry is Y12 level for the most part, but I cannot see how C2H5OH can react with, let alone form an acid, with H2O. If it can, please explain it to me? :confused:

edit: I think you may have made my point with the reference to wine going off once opened. There is alcohol & water mixed with no reaction to create acid for between months and years. That is a reaction between the wine & air. There is no air in a fuel tank with, or without, ethanol, just fuel vapour. So if acid is created, (and I don't deny it), it can't be due to the ethanol & water. But the water may act as a catalyst between the water & something in the fuel. Since water & petrol do not mix, but the addition of ethanol allowing some mixing, that might allow some sort of reaction over time.

But if I am wrong, please tell me! I'm always willing to learn. :)

[Nanook]

Wine going off has nothing to do wioth ethanol/water. That's a reaction between oxygen & the other volatiles in the wine. You'll get the same reacion in low/no alcohol wine.



Actually it sort of does. My explanation was trying to be very simplistic but basically what happens is, as you mention, ethanol reacts with oxygen and this is why wine becomes vinegar which is acidic.

Ethanol + oxygen becomes Ethanoic acid + water

Ethanol is an alcohol and alcohols are soluble in water but it doesn't mix very well with fuel so it separates and then combines with any water (which also contains oxygen) that may be in your tank.

It's this acidic solution that can clean the inside of your tank and causes problems.

[Banshee]

OK. Now THAT makes sense. Thanks.

So if it is there & sits for a long time it can cause corrosion. But a non issue in a DD as enough motion will keep it mixed until used & the turnover is sufficient to prevent it sitting. Unless you get a LOT of water in the tank, in which case you'll be FUBAR either way.

[layback40]

Wine going off has nothing to do wioth ethanol/water. That's a reaction between oxygen & the other volatiles in the wine. You'll get the same reacion in low/no alcohol wine.

I admit my chimstry is Y12 level for the most part, but I cannot see how C2H5OH can react with, let alone form an acid, with H2O. If it can, please explain it to me? :confused:

edit: I think you may have made my point with the reference to wine going off once opened. There is alcohol & water mixed with no reaction to create acid for between months and years. That is a reaction between the wine & air. There is no air in a fuel tank with, or without, ethanol, just fuel vapour. So if acid is created, (and I don't deny it), it can't be due to the ethanol & water. But the water may act as a catalyst between the water & something in the fuel. Since water & petrol do not mix, but the addition of ethanol allowing some mixing, that might allow some sort of reaction over time.

But if I am wrong, please tell me! I'm always willing to learn. :)

You need to have a look at a year 12 chem book, Heineman is a good one. It explains oxidation of ethanol. I can assure you that it occurs, thats how white wine vinegar is made.
Also the problems with the ethanol softening seals etc occurs.

Ethanol & fuel do mix well. An old method for getting condensation out of a fuel tank was to drain the fuel, add a ltr of metho, shake the tank, a then add fuel. The water dissolved in the metho A then the water/metho mix would dissolve in the fuel.
Petrol companies can blend fuels this way to bulk a fuel up with a couple of % water. Most of the ethanol made in Australia contains a few % water as its very hard to get the last of the water out as the mix form an azeotrope.

[Nanook]

So if it is there & sits for a long time it can cause corrosion. But a non issue in a DD as enough motion will keep it mixed until used & the turnover is sufficient to prevent it sitting. Unless you get a LOT of water in the tank, in which case you'll be FUBAR either way.

That's exactly the point I was trying to make :D

There is no harm in using E10 as long as there is a high turn over in both your tank and the servo that you bought it from.

I don't like using E10 personally unless I know I'm going to use a lot of it, for example, if I'm spending the day on the beach which chews up the juice, I'll fill up with E10 because its cheap and I know it will get used.

Any other time I will always use 91 (thankfully my local servo sells both 91 and E10) or 95 because mine's not a daily driver and can sit in the garage for weeks without even being started.

My Hilux only uses E10 and it's never had a problem as it gets filled at least once a week because it's constantly driven.

Now what was the original question? :D

[Banshee]

At least the JK doesn't have to worry about the fuel tank corroding. The only metal part is the tank skid...

And if you are getting water/ethanol/fuel mix on it, you have more to worry about than the water in the fuel!

[Old_Dog]

Quote: layback40
... An old method for getting condensation out of a fuel tank was to drain the fuel, ...

I remember an old Jack Absalom tip thirty plus years ago when filling up with petrol at a one horse town with perhaps dodgy fuel. He suggested pouring in a cup of metho and then filling up with petrol. The metho would take care of any water in the tank or in the servo's petrol.

Old Jack was always full of suggestions on keeping his Chrysler (or Mitsubishi) Stigma going in the middle of nowhere. Most of his shows are available on YouTube if you want a laugh. However, I can tell you that I wouldn't let Jack anywhere near a modern car! He was a funny but talented bugger with a strong opinion on just about everything.

[Banshee]

Aircraft all have drain taps. One of the preflight checks is to drain the water out of the tanks.

When commercial aircraft are at altitude the outside air temp is ~ -45C to -56C (from memory) & the water freezes out of the fuel. After the plane lands, you tended to get rained on after a while, as the ice in the tanks caused condensation & frost on the underside of the wings, which subsequently melted & dripped on you as you worked there...

[OzRick25]

My understanding of the potential issues with ethanol is that in isolation and turned over quickly it's fine CH3CH2OH + 3O2 + heat and pressure = 2C02 + 3H2O big deal carbon dioxide and water your doing plants a favour!

However the problem isnt with the ethanol it's with the sulpher either in the cheap ethanol fuel, or the cheap 91 still in the tank, or in the cheap oil you saved a few dollars on + the modern crank case ventilation and in the case of the 3.8 the bad rings leading to high oil consumption.

S+O2 + pressure and heat = SO2 then + O2 + pressure and heat = 2SO4 then + 2H2O + pressure and heat = 2H2SO4 (sufuric acid) + O2. Also 4SO2 + 2H20 + heat and pressure = 2H2SO4 + O2

Now that sulfuric acid may then react with more ethanol and form ethene and more water but it may stay as acid and damage your engine and exhaust (particularly the cats) as well as the environment.

In Australia the allowable sulphur content in our petrol is 10 times that in the US where our cars were designed and where e10 was considered to be fine (pre 08 it was up to 50 times higher).... A lot of Australians also live in hot humid areas with high water content in the intake air.

Occasional use from a high turnover station and that you use fairly quickly probably won't do any long term damage at all it might even help clean some carbon deposit. Even with prolonged use it's going to take a while for the relatively low levels of sulfuric acid to show you what they have done, but science says they are there and they aren't great for engines.

If you turn your car's over every 3 to 5 years you probably can run ethanol and high sulphur oil in Darwin during the wet season even in the 2 stroke 3.8l and not be concerned. If I had a high compression low oil use engine in a cool low moisture level climate, was confident in low sulpher fuel and used fully synthetic low sulpher oil I'd use e10 all day every day. However my Jeep is long term and for the above reasons I dont .

[layback40]

Aircraft all have drain taps. One of the preflight checks is to drain the water out of the tanks.

When commercial aircraft are at altitude the outside air temp is ~ -45C to -56C (from memory) & the water freezes out of the fuel. After the plane lands, you tended to get rained on after a while, as the ice in the tanks caused condensation & frost on the underside of the wings, which subsequently melted & dripped on you as you worked there...

Aircraft have an inspection sample point & a sample of fuel is taken from each tank during pre flight inspection. If any water or other substance is found in the fuel the aircraft doesnt take off until it is fully investigated. They are not just water drains taps.

[Nanook]

Hopefully the Jeep won't fall as far as an aircraft if water stops the engine.