[doncarlyon]

I always saw a few mpg more using super unleaded (tesco usually)... this was on various turbocharged cars.

Most noticeable on a fiddled with Focus RS.

[1966-TR4]

Originally Posted by AlwynMike

Only ever put premium in my 440.
Don't know if its better and don't really care.
I probably wouldn't notice any performance or consumption gain.

I do admit to a smug smile recently whilst filling up with Momentum to see that it was 4p per litre cheaper than standard diesel.

How much cheaper is it per mile?

Oh.

[AlwynMike]

Originally Posted by 1966-TR4

How much cheaper is it per mile?

Oh.

My previous E91 335d did about the same mpg as the 440 (but the 335 was better consumption with the caravan on the back - by almost 10mpg!!)

[ramparts]

Originally Posted by GEP77

The cost difference for me would mean spending £125 more (and more like £300 if I were to use Shell) on fuel a year to use 97/98/99RON compared to ordinary Tesco fuel. From my personnel experience the difference in mpg between 95 and higher octanes is precisely zero. Driving style makes by far and the way the biggest difference. One of the biggest factors for me recently has been the 50 mph average speed limit on the M23. This has caused my mpg to improve by about 1.5 mpg overall (averaged over a number of months either side of the roadworks being setup.
Incidentally when I ran my car on 99RON (Tesco) it averaged 36.85mpg, when running on whatever 95RON is available (normally Tesco) I've averaged 37.24mpg.

As far as noise and refinement my car sounds awesome whatever version of petrol goes in it.

That's only 30p a day for better quality fuel in a £40,000 car.

[RobUK]

Every single fill-up from day one has been Shell V Power in this car and 33K miles later I've had no problems and have been pleased with the performance so no reason to change as the extra cost isn't bothering me.

[Techno 9000]

As mentioned the higher octane fuel COULD allow the ECU to run more ignition advance, creating more torque / hp in a given situation.

Interesting you say the owners manual and filler cap legend both state 95 RON.

It feels to me as though BMW may have programmed the ECU to run on 95 RON and, if that is the case, no improvement (to torque/hp) may be had by running the higher octane fuel.

I've had a couple of cars where the ECU was programmed to run on 98 RON and, where lower octane fuels were used, would pull back / retard the ignition on detection of knocking on a per cylinder basis. Other strategies it would employ were increasing fuelling to the affected cylinder(s) and if these failed lowering boost request.

[HighlandPete]

Originally Posted by Techno 9000

As mentioned the higher octane fuel COULD allow the ECU to run more ignition advance, creating more torque / hp in a given situation.

Interesting you say the owners manual and filler cap legend both state 95 RON.

It feels to me as though BMW may have programmed the ECU to run on 95 RON and, if that is the case, no improvement (to torque/hp) may be had by running the higher octane fuel.

BMW may 'recommend' RON 95 in literature and on the filler, etc. Does for my car, but that doesn't mean the engine is not set up for RON 98, for best performance and economy. I know my engine is, as stated in BMW's literature for the F11 with the N55 engine. Knock sensors are set up for RON 98, even if it has to 'pull back' for the recommended RON 95 fuel. I believe the reference to RON 95 in the UK, is to limit confusion for most uniformed users.

[tjlees]

For petrol 99 Ron does give more horses - a lot of car mags have proved this and a better throttle response for me - for performance car. Can’t say i’ve Noticed the extra horses - a temp drop is a lot more noticeable.

If you use a petrol or diesel one that also cleans (iirc Tesco momentum doesn’t do this) you will notice a mpg diff if you haven’t used a cleaner such as archoil. I used v power from 50k miles onwards and i’m now getting 600+ miles from a tank at 76mph (gps) 79mph indicated on a long run and a minimum of 500 on all types of other journey on a 335d. Previously I struggled to hit 500 miles.

[Isow]

I use Shell VPower in my Porsche.
Shell says that VPower cleans the engine.
How do I know it actually does ?

[TQMp5135]

Thanks all for the input here!

I had a dig around and managed to dig out the installation certificate for my MPPK. As with the example above, it states clearly that BMW recommends 98 RON fuel in conjunction with the MPPK.

I think I will therefore start using Shell V Power to get the best performance out of my car!
Will let everyone know if I notice any difference (although getting new tyres fitted around the same time as my next fill up so will have to factor that in too).

From my research it sounds like using 95 RON fuel all this time won't have hurt it. It will just not have been running to its full potential. I expect that after a couple of tanks of 98 RON it will start to run just as well as if I'd filled up with 98 RON from the beginning?

Hope so!

[Lorcan]

Originally Posted by HighlandPete

I believe the reference to RON 95 in the UK, is to limit confusion for most uniformed users.

Police, nurses etc.

[Lorcan]

Be aware of the distinction between octane rating and energy content. Octane rating refers to the fuel's ability to resist detonation, also known as knock or pinking. High octane fuels can cope with more boost and/or ignition advance so these often suit engines in a higher state of tune.

However higher octane fuels don't necessarily contain more energy. Lower octane fuels can contain more specific energy and improve the performance of an engine in a lower state of tune that does not require a high octane rating to prevent knock. Putting high octane fuel in a mildly tuned engine can be a waste of time/money and counterproductive.

[Russbmw]

Originally Posted by Lorcan

Be aware of the distinction between octane rating and energy content. Octane rating refers to the fuel's ability to resist detonation, also known as knock or pinking. High octane fuels can cope with more boost and/or ignition advance so these often suit engines in a higher state of tune.

However higher octane fuels don't necessarily contain more energy. Lower octane fuels can contain more specific energy and improve the performance of an engine in a lower state of tune that does not require a high octane rating to prevent knock. Putting high octane fuel in a mildly tuned engine can be a waste of time/money and counterproductive.

That was always my understanding. I cant' say as I've ever noticed any of my stock cars feeling any different on 95 or 98/99.

I'd always considered the higher RON fuels to be required more by the heavily tuned Jap brigade running 450+bhp 2ltr engines.

[creepy coupe]

I was talking to a race engine builder just before Christmas. Who had just carried out a comparison between regular and super unleaded. He found no power advantage on a couple of different engines putting out circa 300-350 BHP.

He did say throttle response was marginally better, due to the slight advance in the ignition curve with super But power wise they did nothing.

[bwrlane]

In my old 330D I tried all fuel types over around 50k miles. There is only one difference I am confident of: BP Ultimate Diesel makes the engine less clattery. While I did not test this in any scientific way, I always noticed it when the wife had filled up the car as she only used ASDA fuel. I am confident that this was not my imagination. I occasionally filled up with Shell premium but don’t think it had the same effect. I noticed no difference with any fuel, in power or economy.

In my 340i I have less experience having only covered 9k miles. However, I noticed no difference with BP Ultimate vs ASDA fuel. Maybe a slight one power-wise with Tesco Momentum 99. I understand Momentum gets its high RON rating by including more Ethanol in the mix. Ethanol is more knock resistant and should also increase power due to better combustibility.

However, Ethanol has a lower specific energy content than Octane, so should in theory deliver worse MPG.

[Steve_M_Sport]

You may as well use snake oil

[HighlandPete]

Originally Posted by Steve_M_Sport

You may as well use snake oil

I've just been looking at a report from one of the tuning companies who tested a Toyota MR2 in standard tune and a BMW E46 M3 CSL in highly tuned form, with different fuels, 95 - 99.

The dyno graphs clearly show both power and torque improvements on the higher octane. The MR2 showed about a 5% gain in power, also shows a decent torque improvement, particularly in the mid range. The M3 CSL yielded over 10% improvement in power, more than a 40bhp difference, 95 vs. 99. Plus a torque improvement across the rev range.

[gippy]

i'm interested in this question but purely from a maintenance and engine health point of view - i ran my car on tesco premium for a few weeks before getting into the shell points game. For 5 months i've been using V power only and nothing else. although up till now iv'e done nothing with those points. they are pretty pointless.

would be nice to get some factual articles and things posted here....
from what i've gathered in 5 minutes on the net, higher octane fuels should be beneficial in cars with higher compression ratios.
https://www.autoexpress.co.uk/fuel/1...premium-petrol

its an interesting topic and i'd be curious to know if the extra £15 odd i'm spending each full tank is actually prolonging the health of the engine or protecting it in someway. i'll continue googling. 2 fills a month...£360 more a year. Which is nothing really, so heck, might as well use V power anyway.

[AlwynMike]

Originally Posted by gippy

.... the extra £15 odd i'm spending each full tank ....

Wow.
I'm glad I'm running Tesco Momentum at around 4p per litre dearer than the standard unleaded (and 5p cheaper than standard diesel).
My rough maths makes it a couple of pounds per tankful dearer than standard unleaded.
How big is your tank??

[Lorcan]

Originally Posted by HighlandPete

I've just been looking at a report from one of the tuning companies who tested a Toyota MR2 in standard tune and a BMW E46 M3 CSL in highly tuned form, with different fuels, 95 - 99.

The dyno graphs clearly show both power and torque improvements on the higher octane. The MR2 showed about a 5% gain in power, also shows a decent torque improvement, particularly in the mid range. The M3 CSL yielded over 10% improvement in power, more than a 40bhp difference, 95 vs. 99. Plus a torque improvement across the rev range.

There is clearly something else going on there are a higher octane rating does not, in itself, make more power. Either the ignition advance is changing or the higher octane fuel has more specific energy.

[gippy]

Originally Posted by AlwynMike

Wow.
I'm glad I'm running Tesco Momentum at around 4p per litre dearer than the standard unleaded (and 5p cheaper than standard diesel).
My rough maths makes it a couple of pounds per tankful dearer than standard unleaded.
How big is your tank??

same as yours aint it?

that was just rough maths, i think V power where i am is around 130 or 140p, so i just said well if regular is around 110, 55 litres... around £12-£16 more, so just took it as £15. 2.5 fills a month for me on average, 2.5*12*15 = £450 annual.

i mean...saving £450 a year is hardly life changing.....and i'd be surprised if it was for people who are running 440i's......but hey we're all different.

Unless i find out that V power has absolutely no benefit to engine life or health, in which case, i will swiftly get back to Tesco regular and my clubcard points...

I'm struggling to find ANY articles where some scientists or at least anyone have done proper tests. All i'm getting is tons of car mag articles which simply quote the fuel companies claims about their fuel..... no actual proof.
Will continue searching.

[HighlandPete]

Originally Posted by Lorcan

There is clearly something else going on there are a higher octane rating does not, in itself, make more power. Either the ignition advance is changing or the higher octane fuel has more specific energy.

There is comment in the report on ignition advance and a graph for the M3 showing the air/fuel ratio across the rev range on the different fuels. Four different fuels were tested.