[Ezzra]

If it is mapped for 98RON then 95RON would cause a lose of power, if it is mapped for 95RON then its just a waste of money mostly.

There are various aspects of the combustion process affected by the octane rating, it can influence ignition timing, boost pressure etc. For instance for many years now cars and motorcycles have used anti-knock sensors to optimise the ignition timing, in simple terms the ECU will advance the ignition until knock (pinking/pre-ignition) is detected and then back it off slightly, this happens per cylinder many times a second.

Therefore even if an engine is quoted as being able to run on, say, 95 RON fuel it is still likely to benefit from a -higher octane fuel.

Granted, but the point above of "BMW have always caveated their performance, power and economy figures, stating they use 98RON" - I cant see evidence of - as it would state it in the owners manual surely?!

They've quoted this with their engine spec for the thirty years I've been around BMWs. It's on the website somewhere.

 

[FishFingers]

If i remember correctly, Fifth Gear did a test on it some years back.
Shell did well - but BP Ultimate was worse than the supermarket stuff IIRC.

 

[FishFingers]

Here it is...

https://youtu.be/WTaBngvsPrc

 

[Ezzra]

Must is too strong a word, any petrol BMW can run on std 95RON and it will not cause any problems.

On more powerful cars (M2/240/140 etc) it is possibly beneficial to use 98/99 ron to achieve max power, but again it is not essential or a MUST by any stretch!

And your average man won't notice the difference either between the two.

My apologies, I didn't articulate it very well.

For the last thirty years or so, BMW have always caveated their performance, power and economy figures, stating they use 98RON.
Yes, 95RON is fine, but you will lose a little of each.
As far as an M car is concerned, I cannot see the logic of putting anything other than the very best fuel in it.

Where is your evidence? The M240i booklet only states a 95RON minimum, no mention of recommended or suggested other types.

If it is mapped for 98RON then 95RON would cause a lose of power, if it is mapped for 95RON then its just a waste of money mostly.

It's mapped for 98RON.

On 95RON the ignition is backed off.

 

[Matthaus]

My apologies, I didn't articulate it very well.

For the last thirty years or so, BMW have always caveated their performance, power and economy figures, stating they use 98RON.
Yes, 95RON is fine, but you will lose a little of each.
As far as an M car is concerned, I cannot see the logic of putting anything other than the very best fuel in it.

Where is your evidence? The M240i booklet only states a 95RON minimum, no mention of recommended or suggested other types.

If it is mapped for 98RON then 95RON would cause a lose of power, if it is mapped for 95RON then its just a waste of money mostly.

It's mapped for 98RON.

On 95RON the ignition is backed off.

But for fear of repeating myself.. the manual does not tell you to use it.

When I had an Impreza it explicitly said 98RON min - not 95

 

[Ezzra]

Where is your evidence? The M240i booklet only states a 95RON minimum, no mention of recommended or suggested other types.

If it is mapped for 98RON then 95RON would cause a lose of power, if it is mapped for 95RON then its just a waste of money mostly.

It's mapped for 98RON.

On 95RON the ignition is backed off.

But for fear of repeating myself.. the manual does not tell you to use it.

When I had an Impreza it explicitly said 98RON min - not 95

Indeed. The manual merely says use a minimum of 95ron.

 

[marco_polo]

The performance and fuel consumption rates listed are based on the use of RON 98 fuel.

You can actually go as low as 91 RON if you need to, but the ignition (and power) will be severely pulled.

 

[binocular]

Just to muddy the waters - I've used AVGAS before in a hill climb car (bit naughty cos it should have been pump fuel) but it made no difference. Still got beaten by better talent ☹

Sent from my iPhone using Tapatalk

 

[Octavius]

The electronic engine management system adjusts the system to whatever RON rating your using.
For daily driving 95 is more than adequate. For hooning or track days use the higher octane fuels.

 

[Ezzra]

The performance and fuel consumption rates listed are based on the use of RON 98 fuel.

You can actually go as low as 91 RON if you need to, but the ignition (and power) will be severely pulled.

I wouldn't even put that it my lawnmower

 

[50pence]

Yes, that's the point, 95 RON is actually pretty decent, in many countries including the US much lower octane fuel is available and as far as I know most BMWs will run on fuel as low as 89 RON, the electronics retard the ignition etc, efficiency and performance are reduced.

However I almost always run my M135i on BP Ultimate or Shell V-Power as the higher octane will enable the engine performance to be optimised.

I think I'm correct in saying the US uses a different measure that the UK RON. So not directly comparable. But yes, for the UK 95 is the lowest

The US states the octane in MON whilst we are RON.

To be pedantic I think the US rating is some kind of average between the two.

 

[50pence]

The performance and fuel consumption rates listed are based on the use of RON 98 fuel.

You can actually go as low as 91 RON if you need to, but the ignition (and power) will be severely pulled.

I wouldn't even put that it my lawnmower

I put super unleaded in my lawn mower, a Honda, as it doesn't go off over the winter.

 

[Hoss]

Just run it on 98/99 RON. It's a performance car, so use performance fuel.

For what it's worth I use Shell V-Power in my M135i.

 

[Mrpink]

I think I'm correct in saying the US uses a different measure that the UK RON. So not directly comparable. But yes, for the UK 95 is the lowest

The US states the octane in MON whilst we are RON.

To be pedantic I think the US rating is some kind of average between the two.

Yep the US pump station using AKI which is the average of RON & MON.

 

[YaoNg]

I wouldn't even put that it my lawnmower

I put super unleaded in my lawn mower, a Honda, as it doesn't go off over the winter.

Aren't you supposed to drain your lawnmower of petrol for the winter to avoid damage to the carburettor? That was a costly mistake I made one year.

 

[GeeDee]

I put super unleaded in my lawn mower, a Honda, as it doesn't go off over the winter.

Appreciating this is an old thread resurrected, why wouldn't SUL go off? Of course it does, in the same way as NUL.

Shell v power imo, bp ultimate or tesco premium if you like but shell v power is recommend for m cars but in the real world there is little seprating them. The internet is full of into om the subject matter but if your driving an m2 premium fuel is a must really.

Sent from my HTC 10 using Tapatalk

Why would you pay such a large premium for 2 extra octanes (bp "not" ultimate) compared with 4 extra for the other two? :?

PS I suggest you sort out your auto-correct on Tapasqawk

 

[JCW2M135i]

Putting worse fuel in your car will not do any damage to it, and the performance delta between 98 Ron and 95 Ron is a lot less than 89 Ron and 95 Ron (89 Ron just makes turbo engines feel flat and make driveability a lot worse such as lumps and bumps).

I do know BMW do a lot of their calibration on 98 Ron then have a clever function to interpret this to 95 Ron so that driveability isn't affected by more knock being active. Also, most of their requirements are 98 specific.

But...you have brought a high performance car that has been developed on 98 Ron - why put cheap fuel in it? Even in reality you will see no difference other than when you drive it hard.

 

[dannym]

She'll V-Power.

 

[5678]

She'll V-Power.

I bet she does!

 

[Deadeye]

Tesco 99 for me.

I found it would allow slightly more boost pressure when I had my 335i and JB4 in automap over Shell v-power.

Also didn't v-power change a year or so ago from 98-97?