I've honestly noticed no difference between E5 and E10 in any respect.

My 2014 1.4tsi Superb runs better and has a slightly better mpg on E5 99 RON petrol - the difference must be between E5 & E10 as comparing before E10 was introduced there was no difference in mpg but it still ran better on 99RON.

With Mrs BJ's 2006 1.2 Panda it doesn't seem to make any difference at all between E5 95 RON & E10 99 RON .

Probably dependent on engine design - eg anti knock sensors etc.

Edited by Big John on 22/11/2022 at 13:16

I've honestly noticed no difference between E5 and E10 in any respect.

That applies to our 2 Skodas, same now as they were before.

But my Caterham is 30 years old and the tank and fuel sender are also 30 years old. Would the tank liner and plastic float be affected by E10, no one can tell me. The fuel system from the tank outlet was all replaced in 2004, a mere 18 years ago, when I replaced the carbs with injection. Are the components I fitted 18 years ago E10 compliant? Only one supplier told me with certainty that his was 100% compliant and that was Think Automotive regarding Moquip TFE fuel hose, the rest said that they could not confirm they were.

So based on that I am using E5 and paying the extra cost. Has there been any improvement in performance and economy? well performance wise it has always been "adequate" (175 bhp in a 600 kg car) so no actual idea but the mpg on the 97 (or 99) RON E5 is slightly worse according to my spreadsheet that it was prior to the changes in September 2021. I used the "regular" petrol before that.

I use E5 in my Yaris, but that's only because I do fewer than 5K miles pa and tend to fill the tank when it's nearly empty for convenience. I don't want the water content separating and causing problems.

I understand aviation petrol contaons zero ethanol, but I suppose I don't have to worry about my Yaris falling out of the sky ;>)

I've honestly noticed no difference between E5 and E10 in any respect.

Ditto with my 16yo Mazda3 1.6 petrol. But then the difference between E5 standard and E5 super unleaded was not much noticeable (about 2-3mpg tops) either.

That was why I previously (and still would) used an injector cleaner addititive like Redex rather than the super unleaded, because the effect of cleaning was the same for a couple of doses of redex as 4 tankfulls of the far more expensive (branded - more cleaning additives) super fuels.

Unless someone's car cannot take E10 or it's engine is otherwise healthy (not gunked up), then E5 should not make much of a difference mpg-wise apart from in performance cars. The difference in cost will more than make up for the small mpg difference that might appear.

If the engine (injectors, say) is gunked up, it's far better to use one of those cleaning additive products, as you get far more band for your proverbial buck than using superfuels.