[Lorcan]

Originally Posted by philmots

This is a rolling road graph from a newish Civic Type R (that’s recommended to use 99ron)

The lower power run is using regular unleaded, the higher figure is a swap to 99ron the tank after.. so the car will pull power using the lesser Ron fuel, whether you’ll actually feel it or not on the road is another story.

I'm inclined to take that dyno chart with a pinch of salt. Partly because of the huge power difference between the two runs (20hp+ in places), but mostly because the correction factor used "Shoot_4F" sounds entirely made-up. Usually the CF would be some kind of internationally recognised standard like SAE or DIN.

I've seen dyno charts before where the corrected barometric pressure would have put the vehicle either in the worst hurricane in history or on top of Everest. Not where I work, obvs...

[DavidXJ]

Originally Posted by bmnut

Mine does too on the M440i and I'm sure it's in the handbook or if not then some other literature I've read that BMW recommends 98 RON for the M440i's B58 engine.
No matter though I like the piece of mind I get using V power fuel anyway as someone else on here alluded too also!

Absolutely. V-Power all the way. If there's a whiff of magical thinking about feeling that 99 fuel will be salubrious for the engine or an improvement for performance, then that's acceptable to me. I'll even go out of my way to find a Shell on purpose--gives me chance to have a spirited B-road blast.

But seriously, OP: if you were lashing up and down the motorway in a 320d that you knew you'd be planning on handing back in 18months time, then you could run it on bargain basement nectar. But for my part, I'm pretty seriously entertaining the prospect of a long-term keeper (given the rampancy of electroevangelism) as others here no doubt are too.

[bmnut]

Originally Posted by DavidXJ

Absolutely. V-Power all the way. If there's a whiff of magical thinking about feeling that 99 fuel will be salubrious for the engine or an improvement for performance, then that's acceptable to me. I'll even go out of my way to find a Shell on purpose--gives me chance to have a spirited B-road blast.

But seriously, OP: if you were lashing up and down the motorway in a 320d that you knew you'd be planning on handing back in 18months time, then you could run it on bargain basement nectar. But for my part, I'm pretty seriously entertaining the prospect of a long-term keeper (given the rampancy of electroevangelism) as others here no doubt are too.

Your last sentence echoes my own personal thoughts about my new car ownership perfectly!
I collected my car yesterday with the customary twenty-five quids worth of fuel in it for delivery and knew that wouldn’t get me home by any stretch of the imagination. Since it was going to be a bit of a ‘driving Miss Daisy’ journey I reckoned on another twenty quids worth would comfortably do it. So paying more than I normally would, but not actually as bad I thought, put the calculated amount in at the first motorway services that sold V-Power. I got home with more than 40 miles range still left in the tank. Shelled (no pun intended) just over a hundred quid more to fill the tank at home with V-Power to the point where the fuel was just about dripping over its chin and worked out it had done 44 mpg from dealership to home. Not too shabby I reckon. Another hundred miles or so today of mixed driving although mostly steady running and 40 mpg return.
I’m entirely happy with that after years of running six cylinder BMWs in the past that would have struggled to do 30 mpg in the same circumstances.
In short the extra cost of V-Power is worth it both in fuel economy due to modern engine technology and the peace of mind it is hopefully keeping all the oily bits in good condition!

[Riccardog]

As a low-mileage user I always user V-power 99 or Esso Supreme. Earlier this year I did a long road-trip in Germany and used Aral 102 all the way.

Didn't feel any difference at all from a performance perspective. And this is also across cars, as I did the same over summer with my other car.

However, I use higher octane rated fuels as they're supposed to burn more efficiently, which makes me think that they're better for engine longevity. Greater efficiency = less heat, less stress, less residue.

The "additives" issue for me is marketing, a selling point at the fuel pump.

[paulockenden]

Engine longevity again. Has anyone ever known a recent Beemer to die when fed with non-super fuel?

I honestly don’t think we need to worry about such things. The engines in our cars are fine with cheapo fuel.

[Riccardog]

Originally Posted by paulockenden

Engine longevity again. Has anyone ever known a recent Beemer to die when fed with non-super fuel?

I honestly don’t think we need to worry about such things. The engines in our cars are fine with cheapo fuel.

How long do you keep your cars? I tend to be 10+ years, so it matters to me.

[paulockenden]

Originally Posted by Riccardog

How long do you keep your cars? I tend to be 10+ years, so it matters to me.

My last Beemer I kept for 15 years. This one will probably be longer.

There’s absolutely no chance of your engine dying because you bought non-super fuel over that timeframe, in my humble. The engines are designed to run (and last) on bog-standard fuel.

I see expensive petrol as being a bit like expensive HDMI leads. Pure marketing.

[HighlandPete]

Originally Posted by paulockenden

My last Beemer I kept for 15 years. This one will probably be longer.

There’s absolutely no chance of your engine dying because you bought non-super fuel over that timeframe, in my humble. The engines are designed to run (and last) on bog-standard fuel.

I see expensive petrol as being a bit like expensive HDMI leads. Pure marketing.

What engine did you run? Pre Direct Injection (DI)?

The issue with DI petrol engines can be carbon build up. Hence walnut blasting being necessary, at relatively low mileage on some DI examples, (BMW's N54 engine being a typical example), to clean out the inlet tract and ports. Part of this can be combustion not being optimum. Yes, BMW have improved oil/vapour separation in the later engines, but DI designs do allow for extra carbon build up, compared to port injection.

Unless we did controlled tests, would be hard to define how much a fuel with the more complex additive package helps to keep an engine cleaner inside. Less contaminated vapour recirculating is obviously better for longevity, with less maintenance and/or drop off of power.

[paulockenden]

You’re more likely to get such build-up from water or tank sludge from the fuel retailer causing poor combustion, and that affects super and big-standard fuels to an equal degree.

[siwatkins]

Interesting article here on it. https://www.caranddriver.com/feature...dodge-charger/

Summary - some differences, not huge.

Not sure how US fuel grades compare to our regular and super unleaded mind you.

I put in the good stuff because I’m not a high mileage driver, and compared to the price of the car, the price of my fuel is dwarfed by depreciation etc. I also figure if I’m going to baby it outside, I may as well inside. Which I think is no more irrational than paying a premium for other consumables like polishes, waxes etc. even if it is probably pointless

[Charlie (Wessex)]

Filled up Esso Supreme last night as it was cheaper than Tesco Momentum.

But interesting article from USA. I don't really care if my car does 0-62 in 4.6 seconds or 5.6. It goes far faster than I need already. But having said that, I do sometimes catch myself thinking "cor blimey that's quick", ie quicker than I expected, and wonder whether this is down to the fuel or whether just my imagination. I do mix 95 and 99 fill ups.

[Lorcan]

Originally Posted by Riccardog

However, I use higher octane rated fuels as they're supposed to burn more efficiently, which makes me think that they're better for engine longevity. Greater efficiency = less heat, less stress, less residue.

The "additives" issue for me is marketing, a selling point at the fuel pump.

Octane rating is a measure of knock (detonation) resistance - nothing else.

Speed of burn, temperature of burn, completeness of burn (stoichiometry), energy density and other factors can all vary independently of the octane rating, according to the make up of the fuel.

It's sometimes assumed, for example, that higher octane fuels contain more heat energy by weight or volume. This is often NOT the case.