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After many years with my 23i and experimenting i finally found the best fuel for my car.
I use a 50/50 blend of Shell E10 unleaded and Sainsbury's super-unleaded.

I wondered being German car they set up/tuned the engines for the ethanol as seeing it was mandated back in 2011 to go E10.

(My local Shell is cheaper than Sainsburys E10)

flybobbie wrote: ↑Thu Sep 22, 2022 9:18 pm I use a 50/50 blend of Shell E10 unleaded and Sainsbury's super-unleaded.

That would be a problem for me; Sainsbury's is 200 yards away but the nearest shell is 15 miles! I could never get near 50/50

I've only used esso for the last 25+ years and more recently only ever use the E5. As from plenty of media articles... E10 has 10% ethenol (plant based ie: containing water) and a combustion engine was never designed to have water on the inside. And saw an artical recently saying that E10 also has a worse fuel economy than E5 so you'll be visiting the petrol garage more often.

So your 23i will have the N52 engine like my first 2 E86s, E91 and current E90 have and BMW recommended a minimum of 98 RON for all of those whenever possible.

And as my nearest filling station was a Tesco I ran them on Momentum 99 RON, which is what I still use in my MC.

Sainsbury E5 is only 97 RON!

Your Shell may be cheaper than Sainsburys for E10 but Shell, BP, Esso and others add silly money to their E5 prices.

Actually my 23i handbook says minimum 93RON.
I find full tank of super unleaded like Shell vpower runs like it's too good for the engine, although it might hit the red line easier..
So i rarely try that. I read it's slower burning fuel, so not much good for normally aspirated.
The mix i find seems to give a more aggressive acceleration.

Best again my MC is Shell unleaded, on super there is more vibration through hand grips.

Johnny h wrote: ↑Thu Sep 22, 2022 10:05 pm I've only used esso for the last 25+ years and more recently only ever use the E5. As from plenty of media articles... E10 has 10% ethenol (plant based ie: containing water) and a combustion engine was never designed to have water on the inside. And saw an artical recently saying that E10 also has a worse fuel economy than E5 so you'll be visiting the petrol garage more often.

Your engine draws in damp air every time it rains, its misty etc. You can also get condensation in the bore if conditions are right. The amount of water in refined ethanol is around 5% ish. It burns off instantly just like moisture in the air.

Good point well made Mark

I think it's 8 gallons of moisture for every gallon of fuel passes through engine.
Problem with ethanol fuels is the longer term storage absorbing moisture, some concerning micro light pilots if they don't use their mogas powered aircraft much.

flybobbie wrote: ↑Fri Sep 23, 2022 7:16 pm I think it's 8 gallons of moisture for every gallon of fuel passes through engine.
Problem with ethanol fuels is the longer term storage absorbing moisture, some concerning micro light pilots if they don't use their mogas powered aircraft much.

I should think a misfire at any sort of altitude is pretty worrying!
Rob

Smartbear wrote: ↑Fri Sep 23, 2022 7:26 pm

flybobbie wrote: ↑Fri Sep 23, 2022 7:16 pm I think it's 8 gallons of moisture for every gallon of fuel passes through engine.
Problem with ethanol fuels is the longer term storage absorbing moisture, some concerning micro light pilots if they don't use their mogas powered aircraft much.

I should think a misfire at any sort of altitude is pretty worrying!
Rob

Well i had water in fuel a few weeks ago, turned crosswind and engine pretty much gave up, did a dirty dive onto alternate runway.
Normally water can get in through fuel caps, but also tank vents, so ethanol in mogas can absorb water.