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Is e10 better than unleaded? Fuel economy, price and performance


A person I have known for many years operated the first dyno business in Cairns before he was devasted by MS.

If anyone knows, he would know, but I have not seen him for a few months, and I will definetly ask him next time we meet.

On one occassion when I had one of our vehicles at his business for a tune-up, he had a customer’s drag strip Mazda RX3 which had a turbo charger fitted to the rotary engine, and was being prepared for a drag meet in Townsville.

He said that it was running on 100% ethanol and the fuel line from the tank had been upgraded to 0.5". caoacity.

Way back when I was in high school, one of my best mates acquired an ex-racing go kart which was powered by a hotted up Villiers chainsaw engine.

We used to drive it along a dead end gravel road but some of the local “fun police” must have complained and the real police confiscated it .

When it was returned to him some time later, it would not start.

Apparently the boy racers at the local police station had attempted to drive it behind the station and had refilled the tank with Super petrol.

I do not recall what my mate said the fuel was but I assume it must have been ethanol aka Shell A., and after he drained and refilled the tank, the beast returned to life,


Perhaps infinitely better is a larger number than necessary.

There are as @phb is suggesting also considerations in the sustainability of ethanol fuel production.

The relative energy efficiency of the production of biofuels and total carbon footprint, and not just the combustion products of the fuel need to be taken into account.

A further factor is the ability of Australia with a large land mass and low population to produce enough feedstock without risk to other land use. Currently less than 2.0% of our petrol fuel needs are provided from local ethanol production. That is a very significant step change.

Dependence on any carbon based fuel still relies on adding an excess of CO2 to the environment where it remains until reclaimed by agriculture etc.

There are risks around methane as a fuel given it is a green house gas many many times more destructive than CO2. (30 times is typically quoted).

It is the principal component of reticulated town gas and LNG (edited not LPG see post following). Although as a fuel it produces approx half the CO2 of liquid hydrocarbon fuels. It is a quick solution to rapidly improve the situation, but it does not eliminate CO2.

The current export industry for LNG (edit not LPG) has substantial losses and CO2 production in Australia. These occur with mining, pumping and compressing the product. The national accounts of fugitive emissions are estimated from data provided by the major companies producing and exporting the LNG!


Yes, fugitive emissions are a problem.

LPG is primarily a mix of propane and butane, not methane.

Yes, neither methane (nor LPG) nor ethanol look like a long term solution to me - but who can predict the future?

Synthesised methane (or ethanol) more or less eliminates the CO2, in the sense of creating a balanced carbon cycle and not causing an increase in atmospheric CO2 - unlike burning fossil fuels. You have to take the CO2 out of the atmosphere first, in order to create the fuel, and when you burn the fuel, you put the same amount of CO2 back. Doesn’t improve the current situation but doesn’t make it worse either.

It’s sort of the difference between something that is theoretically sound but imperfect in practice and (fossil fuels) something that is known to be flawed.


I will never use E10 in my car. When I bought my new car in 2014, I found it was gutless and could barely climb hills and was slow accelerating from the lights. After about six months, I was ready to sell it and buy something else, I really hated driving it.

One day when buying petrol, the service station was out of E10 so I had to buy unleaded. From that day on, the car was normal, I could climb hills with no problems and acceleration is normal.

There’s no difference in fuel economy between the two types of fuel, but a huge difference in performance.


Thanks for the correction. I intended to say LNG which is our principal gas export and is mainly methane CH4 and a dash of ethane. As you pointed out LPG is a different gas mix.

I’ve made an edit.

I’ll blame a Seniors moment for the slip up, although the iPad sometimes makes it’s own interpretation belated. I don’t think it was the iPad this time.


What I want to know is the price of the Premium 98? There’s not even a window on the sign.
I always use Premium 98 because I understand it’s kindest on the wear & tear of the motor, so in the long run, it’s either cheaper in money or hassle terms.
By the way, I keep my cars until they start becoming expensive to maintain or to Register, unlike others who flog their cars & then trade it in for the next new model. I always buy a car with low mileage, but never a new car. I’m not that rich!


NSW has

which can be used to check prices before heading off to the bowser.

Not necessarily the case. Premium 98 has no benefits unless one’s car has been designed to run on it. Otherwise, it would be an expensive choice at the bowser…


The Wollies Fuel app (and probably those competing with them) let you select whatever fuel you need and it shows the local prices for each Woolies servo.


I understand what you mean. Usually they post the E10, standard Unleaded and diesel cost on the big boards outside their stations but there is never any reference to their Premium 95 or 98 prices. One station may charge a certain extra on each type they carry and another may be a few cents different again. If not using phones/apps you first have to pull in and look at the prices on the bowser to find out those costs.


This older thread is relevant. Local Woolies servos have recently upped their 91-95 and 91-98 margins another $0.01 each, to $0.13 and $0.20 above 91, respectively, although not the first off the rank to do so. A note that Vic has changed the rules since that thread re what they have to display.


Hmmm. I can see that I started the confusion. Sorry about that.

In practical terms today in Australia, LPG is an option to fuel your car whereas LNG is not. There is no technical reason for the latter. It is just the lack of infrastructure for it.

(Some metros in Australia run LNG-powered bus fleets but they have the scale and other attributes to deal with the lack of public infrastructure.)

So in a wide-ranging discussion about the “best” fuel to be using for transport - as opposed to the more limited question of whether “e10 is better than unleaded” - we should be mentioning both LNG and LPG, as long as we understand that

  • they are not the same chemically,
  • generally they are not interchangeable (unless an engine or other apparatus has been specifically designed to be bi-fuel for those two fuels),
  • they have different advantages and disadvantages when compared with each other, and
  • they are currently used in different ways in the wider economy.

Unless we find an economically and environmentally viable way of synthesizing the relevant alkane(s) from CO2 and water, I don’t see either LNG or LPG as being a good long-term option for a transport fuel.


Thank you, TheBBG - I appreciate the information.


Thank you, phb. No, my car isn’t turbo charged so I’ll buy 95 from now on. I appreciate the information.


My motor vehicle maintainer told me many years ago not to use E10 in my vehicles (which are around 15-20 years old). This was when there was a government campaign stating that pretty much any car can take it. Apparently ethanol does bad things to engines that have not been designed with it in mind - or more particularly to the rubber and other sealants that are used.

It also uses corn syrup instead of sugar. Disgusting!

As soon as you divide any positive number by zero, you get infinity and thus an infinite difference - thus any sustainability is infinitely better than no sustainability. That said, infinity does not come in just one size.


Are we drifting, full power on opposite lock, wheels spinning in circles until the fuel runs out or the tyres shred?

Neither option is sustainable. Both impose change on our environment.

We just get to defer the inevitable longer using hydrocarbon fuels produced from agriculture as a substitute for a small portion of the hydrocarbons produced from fossil fuels.

Global agricultural production capacity is finite. Our demand for energy if provided through this resource is likely greater than this resource can provide. Every increase in agricultural production takes away from the environment. That includes loss of diversity, natural vegetation, and water resources. There are also agricultural needs for inputs from other resources that are limited in availability.

Zero divided by zero or any number is still zero.
Infinity divided by a finite number is still infinity.
Infinity divided by infinity is undefined.

Sustainability is a concept and not a mathematical number. The concept is not defined consistently or concisely. What is the starting point and what is the end point? Evolution and decay are inevitable.

Since the real world is finite in all dimensions it’s difficult to see how any analysis relating to our finite environment can have an answer that is also not finite. Unfortunately there is insufficient space on the planet for a hotel with an infinite number of rooms.

Philosophically change is inevitable and incremental. We have an opportunity to influence the rate of change or size of the increment. It remains to be demonstrated that we can also change the trajectory.


I think this would be 1 (one).

Dividing two likes equals ones in Maths 101.


Yes, except that the value of infinity may not be equal to the value of infinity, depending upon the infinity you wish to choose.



True but ‘sustainable’ and ‘finite’ are two different things.

By highlighting the ‘finite’ aspect, aren’t you just saying that it could be sustainable but there are too many cars (really too many people)?

Sustainable means that the cycle does not consume any resource and hence can be performed over and over forever (or at least until the sun dies, but by then we have bigger problems than fuelling your car).

I suggested above that we directly synthesise methane from CO2 and water - which is definitely possible - but unless a new process is discovered, that involves intermediate hydrogen in which case perhaps it is better simply to use a hydrogen economy. The point of direct synthesis is that it avoids all the valid issues that you raise regarding land clearing, habitat destruction, diversion of food production etc. But it takes us away from ethanol, and hence e10, and hence the question as asked.

Zero divided by zero is undefined. Zero divided by any other number is zero.


Simply, yes.

But the situation is more complex.

That is a new topic as I might describe it?
Growth, Consumption and Resources.


It’s good to see the correct answer! Although in a practical sense sharing nothing with nobody is the same outcome as sharing nothing with everyone. It is just a little more difficult to find nobody? Although nobody still ends up with nothing. :thinking: Fortunately I’m not a mathematician and can accept my lack of precision in this instance.

There is actually an infinite number of solutions. Infinity is a concept. It is not a real number.

As a comparison?
Zero is both a real and a rational number however maths as @person has responded has a proof for zero divided by zero having multiple possible answers. Hence the result is undefined.

Perhaps someone attempting to divide zero by zero explains the Big Bang.


Getting way OT here folks :wink:

Back to the chase, not a lot of love in my household for E10. Unlike other fuels it contains no lubricant additives and that’s not good news for things like injectors which are expensive items and need them. A reliable source has also told me that for the same reason it’s not great for fuel pumps. Given the negligible savings, reduced performance, and maintenance downside I just don’t see E10 as being worth it.

I use 98 whenever I can get it. Yes it’s dear but the increased response and improved economy (by about 10% in my experience even in cars designed for 91 fuel) are well worth it IMHO.