A few months ago we came across the following article from Topgear (and undoubtedly many of you have already seen it!) and thought we would bring it to your attention again: https://topgear.nl/.../benzine-zonder-ethanol.../ .
Now we don't want to quote the entire article, but in the overview you can see which gas stations that offer 98 octane do or do not mix ethanol (up to 5%, maximum allowed in combination with 98) in it. Now that could be a logical train of thought, but wait a minute, I know enough examples of extremely tuned engines that all fill up with E85 (85% ethanol) and they do super well, so why would ethanol have a negative effect in this case? Isn't 5% ethanol good for the engine & the power?
One of the reasons is that ethanol has a lower energy density than gasoline, about 30% (i.e. with 5% ethanol about 1.5% less energy and with 95 octane in combination with 10% ethanol 3% compared to pure gasoline). This theoretically also translates into the same percentage step in terms of higher fuel consumption, after all you have to consume more for the same energy output.
Another line of thought could be 'but isn't the octane rating of ethanol much higher than regular petrol and doesn't that have a positive effect on knock resistance?' Yes, the octane rating is higher (around RON 110) but that's not how it works (unfortunately), the mix of fuels combined is the advertised RON number (95 or 98), otherwise 95 octane would actually be 96.5 and 98 octane almost 99 octane.
In addition, there are some other disadvantages to ethanol, such as the damage to fuel lines because it attracts more moisture and is therefore not suitable if it remains in the car for a longer period of time (such as winter storage), etc.
Finally, apart from the fact that we always recommend 98 octane fuel (certainly when you want to have the car tuned, but in the case of the 180 HP Abarth 595, for example, it is even required to meet the factory specifications), we basically advise you to fill up with BP (Ultimate) or Shell (V-Power), but as the overview shows, there are fortunately more ethanol-free alternatives available!
