E10 fuel

[GTB]

My understanding is that E rating and Octane are different animals. Octane relates to an engine's propensity to pink ie predetonate. Ethanol is simply the amount of organic fuel as a percentage of the total.

All engines are tuned to use fuel of a certain octane. In the UK all manufacturers tune to 95 octane and use E10. Using a higher octane has no effect on performance or consumption. If a lower octane is used then pinking can occur and can be rectified by retarding the ignition. Today that would require a remap. So conflating the two is meaningless. In fact pure ethanol has a higher octane rating than petrol.

Bluesnose1812,
You are totally correct absolutely no relationship between the Octane rating and Ethanol (E Rating), we should also remember for diesel fuels it has a cetane not an octane rating!

If everybody can please remember the exact wording of the labels on the fuel dispensers and the law that the fuel " May contain up to 5% or 10% Ethanol" so in some instances there may be zero Ethanol or a low concentration, the labels indicate the Max allowed, but amount may vary on each delivery and also where the filling station is in the country.

Of course Porsche and other cars with high teck and tuned engines need the higher octane fuel 98Ron to stop pinking as displayed in user manuals and filler flaps.

All premium unleaded petrol will be marked E5 it is only now in the UK that 95Ron is now marked E10.

The issue with Ethanol it can act like a detergent on older vehichles and cause engine issues but more importantly the fuel lines, tank, orings, in fact anything in the fuel delivery storage and fuel lines up to the engine cant deal with higher Ethanol levels and will basically soften and disintegrate/fail. Thats why you have all the vehichle checkers for you to check age of the car. Having higher ethanol wont affect performance its your bloody fuel storage system that will fail.

If you go to South America there basic fuel is between 90 % and 98% Ethanol with very little hydrocarbon fuel and cars dont have any issues.
My understanding is if you have a Porsche and you can only get 95Ron petrol, put some in to get you to your destination but then fill up with 98+ Ron unleaded afterwards, Note bp Ultimate is only 97 Ron.

GTB

[SAC1]

GTB - in your experience does using premium 98+ grade petrol in a Porsche give a higher mpg compared to 95RON in like for like operating use?

[pmg]

GTB - in your experience does using premium 98+ grade petrol in a Porsche give a higher mpg compared to 95RON in like for like operating use?

and GTB does that vary depending on whether the 95 octane is E5 or E10. I am asking because some 95 users found their MPG dropped when E10 became the standard?

[Bluesnose1812]

Here's an interesting article on the subject

https://www.caranddriver.com/features/a ... e-charger/

[Jon A]

Here's an interesting article on the subject

https://www.caranddriver.com/features/a ... e-charger/

Interesting article but as far as I can see no real world difference to fuel economy or indeed performance on the road, despite minor peaks or troughs in power?

[pmg]

Here's an interesting article on the subject

https://www.caranddriver.com/features/a ... e-charger/

Interesting article but as far as I can see no real world difference to fuel economy or indeed performance on the road, despite minor peaks or troughs in power?

There is no mention of how many thankful they put between the various tests or whether they emptied the tanks between the two octane levels etc

[Bluesnose1812]

Here's an interesting article on the subject

https://www.caranddriver.com/features/a ... e-charger/

Interesting article but as far as I can see no real world difference to fuel economy or indeed performance on the road, despite minor peaks or troughs in power?

There is no mention of how many thankful they put between the various tests or whether they emptied the tanks between the two octane levels etc

"...We performed acceleration runs, 200-mile fuel-economy loops at 75 mph, and dynamometer pulls, running each vehicle on two different fuels and completely draining the tanks in between...."

[AndyC160]

GTB - in your experience does using premium 98+ grade petrol in a Porsche give a higher mpg compared to 95RON in like for like operating use?

and GTB does that vary depending on whether the 95 octane is E5 or E10. I am asking because some 95 users found their MPG dropped when E10 became the standard?

I've run 95 E5, E10 and Vpower E5 in mine. On the same 44 mile round trip to and from work with similar traffic conditions, same route etc, the E10 is by far the worst performing. Mpg dropped from an average (both ways) of 28mpg (using 95 E5) to 26 (using 95 E10). This was measured over the time it took to empty the tank from full.

[GTB]

GTB - in your experience does using premium 98+ grade petrol in a Porsche give a higher mpg compared to 95RON in like for like operating use?

and GTB does that vary depending on whether the 95 octane is E5 or E10. I am asking because some 95 users found their MPG dropped when E10 became the standard?

Afternoon Folks,
Had to go and earn some money there.............

Anyway, lets be simple and sensible with this. Porsche recommend and ask for Min 98 Ron Octane level fuel because of the high compression engines, you can put in lower 95 Ron fuel, but the engine computer and sensors pick up the less energy so ultimately the MPG/Efficiency on a litre per litre comparrison is less. So I would answer the question as follows: If you use Min 98 Ron petrol in a Porsche you should get the MPG the manufacturer expected you to achieve, but remember loads, hills and all the other drivinbg parameters come into play. But certainly driving the exact same way with 95 Ron fuel you will have a lower MPG rate. Typical figures banded about are 0.7% less but thats subjective.

Using 99+ Ron then of course very slightly better MPG than 98 Ron, but if there is a diffrent in cost you are unlikley to gain a financial benefit.

Now going back to E5 and E10 yes, all standard 95 Ron petrol went from E5 to E10 and thats the law, you cannot in the UK purchase ( Publicly) 95 Ron E5.

For those people with cars that can take E10 Fuel and they continued to purchase 95 Ron petrol their MPG will decrease, Ethanol helps the carbon emmissions but has less energy than hydrocarbon petrol so people will see a decrease in consumption. If you want then buy 98 Ron E5 but you will never gain financially on what you spend to getting your MPG typical range back.

What of course muddy's the waters is " May contain up to......" so nobody can really say this happened or that happened as % Ethanol differs sometimes between delivereis and also where you buy your fuel. So a Shell site one side of the road advertising 95 Ron E10 fuel there may be 9.8% Ethanol in it. The Esso site other side of the road also selling 95 Ron E10 has 0.5% Ethanol in it, so those buying from Esso should achieve a slightly better MPG than an identical car and driver driving identical manner on the Shell fuel.

To me there are far far too many variables, and unless you are running considerable distances, you may not see the diffrences or be able to determine where you gained and where you lost MPG.

Pay your money take your chance, This is my first Porsche and when it arrives I will not be ever putting in less than 98 Ron E5 fuel.

Any further questions you know where I hang about!!

GTB

[Jon A]

The price difference between 95 and 98 is around .12p per litre so around £9 per tank full. Would you really get £9 per tank better fuel economy?
Or are you saying there will be some sort of actual damage done by using 95 ron?
Just trying to make some real world sense of a very technical subject here…