Thanks @kezo I’ve just watched both videos and, being thick when it comes to technical issues, I didn’t really follow it all. On his leaderboard he has Shell V-Power first and Tesco Momentum second, but the former had 2.5% ethanol, whereas Momentum had 4% which he implied was poor, but I’ve no idea what that all means. With the X5 variant I am getting, BMW recommend Shell V Power as it’s a high performance engine, but you can use any super unleaded and in fact regular unleaded, whilst not necessarily recommended, can apparently be used without causing any problems (and the BMW dealer just use that on all their high performance cars). I don’t need to worry about maximising performance, as the car has more than plenty of it, but as it’s heavy on fuel I might get some of the fuel cost premium back in better mpg according to owners. The 3 choices that I have for petrol, which I could mix and match, are (using last weeks prices); Shell V-Power £1.499 per litre Tesco Momentum £1.389 per litre Esso E10 regular unleaded £1.309 per litre (this is in my village – the garage doesn’t sell Esso Super Unleaded) I am thinking of using Shell V-Power for the run in period, then Tesco Momentum thereafter, with every 4th refuel using Shell V-Power, but having the regular Esso unleaded as a fall back in an emergency. Given what BMW recommend for the engine, the cost differences above and what the chap on the videos discovered, does this sound sensible to you, or would I be wasting money? Thanks in advance.
Think of it another way you washing machine manufacturer will likely recommend Areiel but you may use Aldi with no adverse effects!
If you look over the pond to the US to try and make more sense of european Research Octane Number (RON), where RON is a measure to withstand compression without causing engine knocking. In the US they use (RON+MON)/2 formula, known as the Anti Knock Index (AKI) to measure octane ratings.
If we search the 60i AKI number, it comes up with an AKI of 91 or higher and recommended 93 if your going to max out its performace. 91 AKI converts to 95 RON E10 (regular unleaded) or E5 (premium unleaded). 93 AKI converts to 97 RON, which both Momentum and V Power exceed.
Whats actually happened is both Momentum and V Power now contain 4% and 2.5% ethanol, which in itself ethanol has high in octane, so over all there will a negligible difference in advertised RON. Whilst not as good as prior to the trade deal as you can see from the tests, V power is 95 RON with etanol removed, where as previously it had been tested at 100/101 RON from just petrol with no ethanol content. It is what it is and as a side effect of the US trade deal, there not alot we can do!
The disadvantage to ethanol is it binds moisture and can increase the amount of water water in fuel and lead to corrosion however, nearly all cars manufactured post 2010 are designed to run on 15% ethanol (E15).
Fuels like Momentum, V Power and Ultimate will normally tout the fuel containts extra detergents, which can help keep the engine cleaner, reduce carbon buildup… Shell is big on marketing of this however, regular fuel contains detergents.
So from that essay, I agree with dealer in that your car will happily run on regular unleaded but I’d run it on premium unleaded E5 or the cheapest of Tesco, BP or Shell super unleaded (BP Ultimate 97 RON) and do a 4:1 as you suggested or ut the odd bottle of Redex etc in every now and again. Its not as though your going to tickle its full potential on a daily basis.