[HampshireUK]

I know the M40i isn’t a car you buy when concerned about MPG and fuel costs. My current M235i has been run on 99 octane fuel,super unleaded, since I have owned it but it’s getting a bit crazy at up to 12p per litre more than normal unleaded !

Those M40i owners in the UK are you running normal 95 octane unleaded or the 97/99 octane super unleaded fuels, also ido you notice much difference in performance, assuming you are past the running in period

Thanks

[RichM50d]

I just run mine on normal. How often will you actually get to see the performance benefits of super on our roads?!

[BMWGuySweden]

I've used about 50/50 95 vs 98.

Don't really notice a difference.

[teaston]

Originally Posted by RichM50d

I just run mine on normal. How often will you actually get to see the performance benefits of super on our roads?!

Then why didn’t you get the 20i, how often will you get to see the performance benefits of an M40i?!

[RichM50d]

Originally Posted by teaston

Then why didn’t you get the 20i, how often will you get to see the performance benefits of an M40i?!

Regularly. But if you can see the benefits of super over regular, on our roads, I’d be impressed.

[ep22jg]

A few years ago, I tried both when I had my Audi S4 and came to the conclusion that the 'super' fuel gave slightly better mpg which offset the extra price.
That plus the additives, I used it all the time!

[teaston]

Originally Posted by RichM50d

Regularly. But if you can see the benefits of super over regular, on our roads, I’d be impressed.

Maybe tried back to back there's a little difference, but then there's also the cleaning additives that will keep the performance better over the life of the vehicle, plus with performance turbo engines there is also the reduction of engine knock.

I would certainly use super unleaded whenever possible.

[jbtco]

Can’t get super locally, ocasionally use when on a road trip.

[strike4A]

Only super I go for is Shell V-Power so the tank can be sometimes a mix.

Booked in at Surrey Rolling Road on 24th November for a power run on their dyno so will ensure only Shell V-Power is in there.

[MarkyM]

M40i is designed to run on 91 Ron Minimum which I don't think we get in the UK anymore? 95 Ron is the recommended grade, you'll only get engine knock problems if a lower grade fuel is used

Certainly 10-20 years ago performance engines were recommended to use 98 Ron but now the sulphur content has been reduced in 95 Ron it's not so much of an issue with deposits but certainly no harm in using higher grade fuels

Personal preference though, I have used both and not noticed a difference, economy hard to compare but seemed the same to me

[Arcanum-UK]

With my current M2 (I pick the M40i up today), I've had a couple of occasions where the car has felt a little sluggish with a bit less 'shove' when accelerating on slip roads or off roundabouts. Both times I found out that my wife had filled the car up with fuel and used normal unleaded. I've felt the same thing in my previous M235i and M135i cars when I couldn't find Super Unleaded.

You can tell. I don't expect the N55 in the M2/M135i/M235i to be fundamentally different from the B58 in the X3 M40i in this regard.

Does it matter? Probably not. The car runs just fine on 95-Octane Unleaded and the power reduction is very small and only just noticeable on full-throttle. Actually, I find the responsiveness more noticeable.

Yet you've paid £50-60K on a car, will pay £1,000 to change the tyres (if you're on 21" wheels) and, as noted, the fuel economy on Super is better. So why wouldn't you use it?

M40i is designed to run on 91 Ron Minimum which I don't think we get in the UK anymore?

I think this is the US octane measurement. RON+MON / 2. The measurement in the UK and Europe is RON. 91 octane in the US is about the same as 95 octane in the UK.

When I was a kid (a long time ago) I vaguely remember 93 octane in the UK, but don't think we had anything lower.

[teaston]

Originally Posted by Arcanum-UK

With my current M2 (I pick the M40i up today), I've had a couple of occasions where the car has felt a little sluggish with a bit less 'shove' when accelerating on slip roads or off roundabouts. Both times I found out that my wife had filled the car up with fuel and used normal unleaded. I've felt the same thing in my previous M235i and M135i cars when I couldn't find Super Unleaded.

You can tell. I don't expect the N55 in the M2/M135i/M235i to be fundamentally different from the B58 in the X3 M40i in this regard.

Does it matter? Probably not. The car runs just fine on 95-Octane Unleaded and the power reduction is very small and only just noticeable on full-throttle. Actually, I find the responsiveness more noticeable.

Yet you've paid £50-60K on a car, will pay £1,000 to change the tyres (if you're on 21" wheels) and, as noted, the fuel economy on Super is better. So why wouldn't you use it?

I think this is the US octane measurement. RON+MON / 2. The measurement in the UK and Europe is RON. 91 octane in the US is about the same as 95 octane in the UK.

When I was a kid (a long time ago) I vaguely remember 93 octane in the UK, but don't think we had anything lower.

I think he's taking the different octanes into account, they should run on 87 US octane which is equivalent to 91 RON

[MarkyM]

Originally Posted by Arcanum-UK

I think this is the US octane measurement. RON+MON / 2. The measurement in the UK and Europe is RON. 91 octane in the US is about the same as 95 octane in the UK.

When I was a kid (a long time ago) I vaguely remember 93 octane in the UK, but don't think we had anything lower.

No it's definitely 91 RON BMW state as the minimum grade so there is a bit of headroom built in by using 95 RON, US uses Octane ratings

91 RON used to be the old standard unleaded rating in U.K. and Super Unleaded was 95 RON, I do notice some brands still call 95 RON super unleaded

[smanji]

In my current car i absolutely notice the difference in throttle response, engine idling and acceleration as well as engine braking when I use Premium Petrol. When I use lower octane fuel the car can feel quite sluggish in lower RPM's and the car becomes very jerky when coming to a stop in low gears. (this could be due to the car ECU being accustom to higher grade fuel)

I did a personal test a few years ago of all the popular higher octane fuels, BP Ultimate gave the best MPG with a slight performance increase, Tesco Momentum and Esso synergy was by far the worst in regards to MPG, shell V-Power provided a balance of performance and an additional 40-50 miles extra per tank.

As previous comments state its also about prolonging the engines life, which many people often over look when trying to justify the extra cost and only look at pence per mile.

The M40i manual states not to use any fuels with ethanol rating above E25 (Ethanol can cause damage to engines and reduces fuel less efficiency), the majority of RON 95 in UK forecourts have around 5% as required under the governments RTFO. Many Pumps in the UK will start to sell E10 but pumps will be marked accordingly (as many cars engines are not able to use E10 or above). Esso claim their Premium Unleaded has 0% ethanol https://www.esso.co.uk/fuels-faqs, BP ultimate also claim to have no ethanol content: https://www.bp.com/content/dam/bp-co...tane-power.pdf.

Based on my own reasoning I would rather fill the engine with fuel that contain as little to no ethanol as possible, I am sure others will agree!

The manual recommends RON 95 and a minimum of RON 91, the vehicle has knock sensors so different petrol grades can be used, so it is entirely up to the driver what fuel they decide to use...obviously not E25+.

I will more then likely continue to use the premium stuff when the M40i arrives!

**edited**

[MarkyM]

Originally Posted by smanji

The M40i manual states not to use any fuels with ethanol rating of E10 or E25 and above([COLOR="Red"]Ethanol can cause damage to engines and reduces fuel less efficiency[/COLOR]), the majority of RON 95 in UK forecourts have around 5% as required under the governments RTFO. Many Pumps in the UK will start to sell E10 but pumps will be marked accordingly (as many cars engines including the M40i are not able to use E10 or above). Esso claim their Premium Unleaded has 0% ethanol https://www.esso.co.uk/fuels-faqs, BP ultimate also claim to have no ethanol content: https://www.bp.com/content/dam/bp-co...tane-power.pdf.

Based on my own reasoning I would rather fill the engine with fuel that contain as little to no ethanol as possible, I am sure others will agree!

The manual recommends RON 95 and a minimum of RON 91, the vehicle has knock sensors so different petrol grades can be used, so it is entirely up to the driver what fuel they decide to use...obviously not E10+.

Not sure where you got your info from or just mid-read it but BMW recommend not using fuel with an Ethanol content of above 25% on M40i, there will be no problem using E10 fuel

[Arcanum-UK]

@ smanji

Good to see another EP3 person coming over here! I had a non-facelift EP3 CTR from 2003-2004, then a Premier EP3 from 2006 to 2013. After that it was M135i, M235i and M2 for a few more hours.

I reckon the EP3 CTR was the most fun car I've owned. Like a go kart, lightweight, stunning gear shift and so rewarding to rev-out to 8,000RPM. I still miss it... though I suspect I'm going to miss my M2 after some time in an X3 (it's an enforced change for family reasons).

Back on topic, agree with your points on how noticeable 95 is compared to 97/98/99 Super.

[smanji]

Originally Posted by MarkyM

Not sure where you got your info from or just mid-read it but BMW recommend not using fuel with an Ethanol content of above 25% on M40i, there will be no problem using E10 fuel

you are correct! i mis-read that bit...was before the morning coffee. Still would avoid using ethanol primed fuel in my cars

[smanji]

Originally Posted by Arcanum-UK

@ smanji

Good to see another EP3 person coming over here! I had a non-facelift EP3 CTR from 2003-2004, then a Premier EP3 from 2006 to 2013. After that it was M135i, M235i and M2 for a few more hours.

I reckon the EP3 CTR was the most fun car I've owned. Like a go kart, lightweight, stunning gear shift and so rewarding to rev-out to 8,000RPM. I still miss it... though I suspect I'm going to miss my M2 after some time in an X3 (it's an enforced change for family reasons).

Back on topic, agree with your points on how noticeable 95 is compared to 97/98/99 Super.

exactly why i plan it keep it along side the M40i! (also purchased due a growing family)

[BMWGuySweden]

In Sweden, unfortunately, both 98 and 95 has 5% ethanol. Otherwise, I would go with 98 every time.

[MarkyM]

Originally Posted by smanji

you are correct! i mis-read that bit...was before the morning coffee. Still would avoid using ethanol primed fuel in my cars

Glad you found it, had to re-read it a few times in case I was mis-reading it, they have worded it strangely

It's all down to personal preference and what anyone is happy using, I always dabble with it when I get a new car then realise I personally can't see any difference so just go the normal route, with 360hp this thing certain never feels sluggish and I trust BMW know what their doing recommending 95 but could be wrong

Your right to go for the E0 premium option though as that should definitely get an effect on MPG, they reckon when we go up to E10 possibly in 2020 it will reduce MPG by 3% but I'm a fairly low mileage user and not too worried about mpg

[Captain_H]

This is a good video, comparing hp between 3 premium and a couple of standard petrol options

[RocketRomeo]

Originally Posted by Arcanum-UK

@ smanji

Good to see another EP3 person coming over here! I had a non-facelift EP3 CTR from 2003-2004, then a Premier EP3 from 2006 to 2013. After that it was M135i, M235i and M2 for a few more hours.

I reckon the EP3 CTR was the most fun car I've owned. Like a go kart, lightweight, stunning gear shift and so rewarding to rev-out to 8,000RPM. I still miss it... though I suspect I'm going to miss my M2 after some time in an X3 (it's an enforced change for family reasons).

Back on topic, agree with your points on how noticeable 95 is compared to 97/98/99 Super.

I had the 2009 FN2 CTR... +1bhp on yours and wow what a difference it made to the chunky heavy model! Lol!

Fun car and I was young so it was "cool"... but actually it wasn't very good at all and people on the forums spent thousands to squeeze 10-20 bhp more... crazy.

I understand the EP was "the" CTR to drive... today's versions are nuts now though!