Quality of Fuel with and without Ethanol

[Rally Pack 2000]

Im not sure on the variation of fuels offered in the UK but we have various offerings here with and without Ethanol added. The Mk2 Escort uses an Ethanol free Premium 98 octane fuel. (Interestingly the factory manual stipulates a 100 Octane British 5 Star for the Twincam but we never ever had that fuel ever short of an airfield!) But for the runaround cars like my Mk2 Focus with a 2lt Duratech engine I have generally put in the cheapest fuel available with a 94 Octane fuel that contains 10% Ethanol. The car seems to run ok on it but nothing outstanding. Recently the price of fuel dropped so much that I thought I would put the 98 Octane Ethanol free fuel in it with a bottle of injector cleaner just to flush the fuel system out. It ran notable smoother at idle an town driving. I put that down to the injector cleaner doing its job but the moment I switched back to the E10 94 that slight roughness came back. Again its not hard and not misfiring or anything, just best described as a hesitancy. Also you can never be 100% sure on these things but the tank of 98 without Ethanol seem to last notable longer. I have heard the fuel company pitch that you get better economy on the premium fuel but never truly believed it. With the premium 98 fuel being 30 cents a litre more your fuel economy would have to be 15 to 20% more to justify the price. So do you see the same situation there? Do you balance difference fuels between your every day car and your classics?

[Xp197777]

Yes I put 98 in all my classic cars and E 10 in modern stuff. Main reason being the E 10 eats the rubber pipes carburettor components in the older cars and it doesn’t store well

[Dave Knight]

Same as Mark, E10 in my MK2 Focus and E5 in the Ezzy. 

[Miniliteman]

You cannot compare the old (70's) fuel to todays fuel, think only of lead content.

Use Shell V-Power 98 fuel in the Mk2, officially it's a E5 fuel but Shell states it does not contain any ethanol. Used to buy 102 octane Racing fuel for it but that is no longer available. My daily driver (Subaru) also uses the same fuel and the engine runs noticably smoother on that compared to E5 plus it is approx. 10% more fuel-efficient.

[Rally Pack 2000]

3 hours ago, Miniliteman said:

You cannot compare the old (70's) fuel to todays fuel, think only of lead content.

Use Shell V-Power 98 fuel in the Mk2, officially it's a E5 fuel but Shell states it does not contain any ethanol. Used to buy 102 octane Racing fuel for it but that is no longer available. My daily driver (Subaru) also uses the same fuel and the engine runs noticably smoother on that compared to E5 plus it is approx. 10% more fuel-efficient.

10% increase in efficiency would definitely bring me much closer to warranting the costs of our V-Power 98 for example. They used to say that premium unleaded costs 15 cents more per litre to manufacture but at the pump its at leats 30 cents to 45 cents more expensive so fuel companies do seem to price gouge on the better quality fuels. I just used to think the Focus had a small tank being an imported car and not quite big enough for our longer journeys but that tank of 98 just seems to get me well past the usual weekly top up well into the second week. That prompted me to start this thread if it was my imagination or not?

[guido]

No 1% Ethanol in an old classic car. Shell exellium 98 does not contain Enthanol ( as they say ) . I fuel up my car with this. Price at about € 2,25 / Liter in my country.

And i used to have some lead substitute in the past. But how trustworthy is it, or was it? I do not know for sure.

Edited August 15, 2025 by guido

[Miniliteman]

20 minutes ago, guido said:

Shell exellium 98 does not contain Enthanol ( as they say ) . I fuel up my car with this. Price at about € 2,25 / Liter in my country.

Shell has V-Power, Total has Excellium. I fill the tank in Belgium, € 1,70 / liter for V-Power 😀

[guido]

Quote

Shell has V-Power, Total has Excellium. I fill the tank in Belgium, € 1,70 / liter for V-Powe

Yes, sorry i mixed it up

I just talked to Jarno, you may know him. Fuel in Germany has better quality, besides that it is no problem to have unleaded on an old car. 

He told me that it is to life of valve seats, that is so minimal, not to worry about to much with less than 2000 miles in a year. Adjusting valves in time...

He also told me on my question what is the best fuel, that the Aral 102 or the BP 98 was the best. And for sure in Germany.

Lucky me, i live next door to germany.

Edited August 15, 2025 by guido

[Miniliteman]

5 hours ago, guido said:

He also told me on my question what is the best fuel, that the Aral 102 or the BP 98 was the best. And for sure in Germany.

Did he test all the available fuels?

[guido]

i don't know. 25 years experience in tuning engines and dyno testing he has. seen many cars from road to race rally

so i think he did some test.

Edited August 15, 2025 by guido

[Rally Pack 2000]

On 15/08/2025 at 20:56, guido said:

No 1% Ethanol in an old classic car. Shell exellium 98 does not contain Enthanol ( as they say ) . I fuel up my car with this. Price at about € 2,25 / Liter in my country.

And i used to have some lead substitute in the past. But how trustworthy is it, or was it? I do not know for sure.

 

On 15/08/2025 at 21:20, Miniliteman said:

Shell has V-Power, Total has Excellium. I fill the tank in Belgium, € 1,70 / liter for V-Power 😀

And here I have been complaining about paying the equivalent of 1.20 Euros for our V-Power 98! I didnt think it was possible to tax and excise fuel any higher than us but they seem to over there!

[guido]

@Rally Pack, Netherlands is by far the most Tax robbing money country there is. About 65-70% is tax on fuel.

Edited August 17, 2025 by guido