[NISFAN]

Lol,ok thought the conversation had drifted onto fuels in general.

I don't have enough experience on diesel fuel. Diesels don't suffer from knock so fuel knock levels are not relevant.

So they must have a higher calorific additive that makes more power. I think some diesel racers use methanol in the mix.

[MaestroAl]

I'm in the same boat - I understand octane as an anti-knock component of petrol: my own car requires a minimum of 98 RON on its current tune, that being V-Power or Momentum only If I ran it on My Mum's Happy Shopper fuel, the ECU would back of massively and I'd probably lose 30bhp or more as the engine tries to avoid detonation

From the little research I've done in the last couple of days, Diesels use Cetane to boost "something" that makes them betterererer fuels BP Ultimate is literally diesel + injector cleaners + a LOT of Cetane apparently.

I have no idea what the chemistry is because it certainly isn't knock related but cetane's where it's at apparently.

The reality, however, is that you WILL NOT GET VALUE from using premium fuels - only use it if your car NEEDS it. I don't care if you get another 10bhp or whatever but it just ain't worth it. BP Ultimate is literally 10p per litre more than BP normal! That's what, £6? (I don't know how big the F30 tank is) Well that's about a gallon of fuel. Does it really give you 50 miles extra mileage? Is 10bhp (in a diesel!) really any difference at all? It's madness I tells ye

[rjberry]

Originally Posted by MaestroAl

The reality, however, is that you WILL NOT GET VALUE from using premium fuels - only use it if your car NEEDS it. I don't care if you get another 10bhp or whatever but it just ain't worth it. BP Ultimate is literally 10p per litre more than BP normal! That's what, £6? (I don't know how big the F30 tank is) Well that's about a gallon of fuel. Does it really give you 50 miles extra mileage? Is 10bhp (in a diesel!) really any difference at all? It's madness I tells ye

Well, I think that settles it for me

When I filled up with the super diesel I had the fuel reserve message on. I thought the F30 diesel had a 57 litre tank but the last time I only managed to squeeze 49.4 litres in before the clunk. The last time it was 153.9 per litre compared to 143.9 for regular diesel. Just under £5 extra.

So far I haven't noticed any great increase in mpg, it may be 1-2mpg higher but seeing as I've paid the extra £5 I don't think I've got a good return there. The car does seem to be smoother now but maybe that's just the placebo effect or my wallet trying to convince me it wasn't all bad

I don't mind paying a couple of pence per litre more than a supermarket but an extra 10p on top of that for a negligible increase may be pushing things a bit far. All those extra fivers are better spent elsewhere

[NISFAN]

Well said maestroAl, my thoughts exactly

[HighlandPete]

Are you guys just looking at cost per mile as you drive, or the possible long term use and longevity to injection systems and cleaner EGR systems and the like? Remember a lot of the injection equipment makers also supply additives to enhance the life of injection equipment. Companies like Delphi and Stanadyne are in this group. Many in the industrial segment use product like Forte and Coundown as a matter of course, to give engine longevity and reduce long term servicing/maintenance costs. The additive package in premium fuels is not to be viewed just on a short term basis.

Cetane is important to efficient fuel burn, so getting fuel with higher cetane rating (around 55) will help smooth out the flame burn and make for better combustion efficiency. This has an effect on soot levels and particulate matter. Premium fuels typically show a lower Bosch smoke level.

We feel the change in many performance diesels, they are quieter for one thing, as diesel combustion knock is less.

Some engines do return more mpg on premium fuels, but short term costs are most likely more expensive. But imagine down the line, when internal parts are cleaner, less coke in the ports and valves, EGR valve is typically cleaner with premium fuels and/or additives. Even the oil contamination between services, is a factor for why a premium fuel could be worth using.

If you are trading the car after a few thousand miles then take your pick. But if you intend to do 200,000 miles with the engine, then you may want to consider the way your diesel is used and how that could effect longevity and maintenance costs long term. Simply another 40k miles from the injectors could cover the fuel cost difference.

It's all a gamble anyway, but some do see added benefits to using a premium fuel. Just widen out the thinking, not just the cost per mile today.

HighlandPete

[JOHNBMWM5]

Originally Posted by HighlandPete

Are you guys just looking at cost per mile as you drive, or the possible long term use and longevity to injection systems and cleaner EGR systems and the like? Remember a lot of the injection equipment makers also supply additives to enhance the life of injection equipment. Companies like Delphi and Stanadyne are in this group. Many in the industrial segment use product like Forte and Coundown as a matter of course, to give engine longevity and reduce long term servicing/maintenance costs. The additive package in premium fuels is not to be viewed just on a short term basis.

Cetane is important to efficient fuel burn, so getting fuel with higher cetane rating (around 55) will help smooth out the flame burn and make for better combustion efficiency. This has an effect on soot levels and particulate matter. Premium fuels typically show a lower Bosch smoke level.

We feel the change in many performance diesels, they are quieter for one thing, as diesel combustion knock is less.

Some engines do return more mpg on premium fuels, but short term costs are most likely more expensive. But imagine down the line, when internal parts are cleaner, less coke in the ports and valves, EGR valve is typically cleaner with premium fuels and/or additives. Even the oil contamination between services, is a factor for why a premium fuel could be worth using.

If you are trading the car after a few thousand miles then take your pick. But if you intend to do 200,000 miles with the engine, then you may want to consider the way your diesel is used and how that could effect longevity and maintenance costs long term. Simply another 40k miles from the injectors could cover the fuel cost difference.

It's all a gamble anyway, but some do see added benefits to using a premium fuel. Just widen out the thinking, not just the cost per mile today.

HighlandPete

Some very interesting points here, I personally do not keep my cars long enough to bother with "high end fuels"but these fuels could help some longevity issues.

[MaestroAl]

All diesels have injector cleaner in them and they're all low sulphur now too. No diesel in the UK will damage your engine over any length of time. Still, that being said, I tend to put a tank of posh in around 1 in 10 ... just for good measure

[NISFAN]

I put the odd tank of diesel in too, to flush the smell of fish and chips

[HighlandPete]

Originally Posted by MaestroAl

All diesels have injector cleaner in them and they're all low sulphur now too. No diesel in the UK will damage your engine over any length of time. Still, that being said, I tend to put a tank of posh in around 1 in 10 ... just for good measure

I'm not sure anyone is thinking damage, but causing damage and assisting longevity are not the same thing.

Premium fuels typically have a higher dosage of cleaning detergents and lubricity enhancers.

ULS diesel was the cause of a lot of injection equipment failures when first introduced, as sulphur has lubricity properties. Hence why products like Millers were used by many diesel users to combat the lubricity defficiency.

HighlandPete

[MaestroAl]

But the reality is that the injectors will last well over 100k miles even with the cheapest fuels, probably twice that. And at an extra 10p per litre, the fuel still doesn't pay for itself even if you factor in having your injectors cleaned or replaced. Besides. you can always run an injector cleaner through the system once a year for the price of ... a few litres of posh.

It's easy to justify any luxury - after all, none of use needs a 3 series but we justify it and so anyone who uses posh diesel wants to feel they're getting something for their money. And they are getting something for their money, just not much and not their money's worth. That doesn't make it rational and posh fuel never ever stands up to purely rational analysis.

[HighlandPete]

I suppose on a forum where the cars are new, the issue isn't so important as older higher mileage cars. A new engine will be running near to optimum, on any BS approved diesel fuel.

The issue really comes to play when engines start getting full of deposits, inlet tracts start gooing up and EGR valves fill with coke. But as performance and efficiency drop off gradually, it is often not noticed.

So if mpg were to drop gradually, say 0.5mpg per 10k miles, by 80k miles there could be a 4mpg shortfall compared to a new engine. But who's keeping records for engine efficiency against mpg? Hardly anyone really keeps exact records for mpg on a given run anyway, as variables are so wide. Let alone for over 100k, or 200k miles.

But forums are full of "why doesn't my diesel get decent mpg anymore?" "My mpg has fallen off, what is wrong?" type questions, and "I've just cleaned my inlet manifold and EGR valve and the engine runs better, gives more mpg", etc., etc.

Also, unless you were to run two engines and treat them to different fuels over say 100k miles, who will have data on "what is what" for performance, wear, injector efficiency, mpg, deposits, oil contamination, etc., etc., to compare how each fuel works long term.

Another point, who's bothered about engine oil performance over long service intervals? Just a few users, who for various reasons will have shorter periods between oil changes, whatever the CBS suggests. But even that is usually based on viewpoint, rather than the exact science, some have experience, but a gut feeling in most instances.

I suppose it is the old saying "we pays our money..... "

HighlandPete

[JOHNBMWM5]

Originally Posted by HighlandPete

I'm not sure anyone is thinking damage, but causing damage and assisting longevity are not the same thing.

Premium fuels typically have a higher dosage of cleaning detergents and lubricity enhancers.

ULS diesel was the cause of a lot of injection equipment failures when first introduced, as sulphur has lubricity properties. Hence why products like Millers were used by many diesel users to combat the lubricity defficiency.

HighlandPete

Yes this is true and I used Millers when I was unable to buy new cars, I believed in it and used it all the time, to what result no idea.

[JOHNBMWM5]

Originally Posted by HighlandPete

I suppose on a forum where the cars are new, the issue isn't so important as older higher mileage cars. A new engine will be running near to optimum, on any BS approved diesel fuel.

The issue really comes to play when engines start getting full of deposits, inlet tracts start gooing up and EGR valves fill with coke. But as performance and efficiency drop off gradually, it is often not noticed.

So if mpg were to drop gradually, say 0.5mpg per 10k miles, by 80k miles there could be a 4mpg shortfall compared to a new engine. But who's keeping records for engine efficiency against mpg? Hardly anyone really keeps exact records for mpg on a given run anyway, as variables are so wide. Let alone for over 100k, or 200k miles.

But forums are full of "why doesn't my diesel get decent mpg anymore?" "My mpg has fallen off, what is wrong?" type questions, and "I've just cleaned my inlet manifold and EGR valve and the engine runs better, gives more mpg", etc., etc.

Also, unless you were to run two engines and treat them to different fuels over say 100k miles, who will have data on "what is what" for performance, wear, injector efficiency, mpg, deposits, oil contamination, etc., etc., to compare how each fuel works long term.

Another point, who's bothered about engine oil performance over long service intervals? Just a few users, who for various reasons will have shorter periods between oil changes, whatever the CBS suggests. But even that is usually based on viewpoint, rather than the exact science, some have experience, but a gut feeling in most instances.

I suppose it is the old saying "we pays our money..... "

HighlandPete

I had the M3e90 and then the M6, followed but the F10 550i M Sport, I never used premium fuels in any of them, yes I could afford it, but NO I did not use it, and I could not see any difference on testing one against the other in most driving conditions, so I used the cheaper SHELL. I never had a problem and saved if you like £100's of pounds. Tight barstuward ....not really.

[DieselRocket]

This is obviously a contentious topic, but I'd add one thought into the mix: don't be swayed by advertising hype. Instead, take an easy step and try if for yourself. Then use your head, your hands, feet and bum-on-seat to make up your own mind. If you don't experience any improvement, go back to bog standard.

In my experience over the years, my E46 M3 responded well to Shell Optimax (highest octane I could buy locally back then). The difference: smoother and and quicker throttle response and a useful bit of extra go at the upper end of the rev range (circa 6,500 to 8,200). No significant gain in power or torque lower down. But, for the smoothness and responsiveness alone, I went Optimax all the way. The difference wasn't a 'slap in the face' thing, but very obvious to any keen driver tuned into their car. Given the way I drove that car, my interest in economy was zero - never checked versus standard fuel.

More recently, E39 530d M Sport (tuned with hybrid blower, re-worked intake system, Eibach anti-roll bars, springs & AP Racing brakes - 300BHP and 470 ft/lbs). Tried both Shell V-Power diesel and BP Ultimate diesel. Both made a noticeable difference, the most obvious change being smoothness and consistency of pickup. There was more grunt in the 2,000 to 3.500 rev range and I consistently got 3-4 more mpg, especially on a long motorway run. Again, I wasn't especially into making a saving and I'd guess I was level-pegging on cost at best, or more likely a bit down, but the drive was improved to the extent that I would always look for one of these fuels first and take normal fuel only as a fall back.

As someone else mentioned - it's not just he extra cetanes, but the cleaning agents are worth taking into account if you care about the car. I learned the value of this recently when I had all my injectors replaced on the E39 - made an incredible difference.

One other thing - if you make the switch, you won't feel all the benefit until you've run through 2 or 3 tanks.

I guess some of you will be bike riders and here you can multiply the impact of premium fuel by a factor of two, just because bike engines are so much more highly tuned (180 BHP from 1300 cc 4-pot engine). I have a BMW K13s and it loves the premium fuels. I never find much difference in power, but there is a big difference in smoothness and consistency of throttle response and, if you ride a bike, you'll know how much that matters. One time, on a touring trip in France, I was forced to fill up with 95 octane fuel (on an older K1200 R Sport) - I got half a mile down the road, lost power and stalled. All my mates had to wait while I tried to restart the bike - got it going, but it ran like a dog for the next 100 miles. Never, ever, ever again in a fast bike ...

I'd guess none of this stuff makes a saving overall , unless you take the long view on keeping the system clean and reduced long-term maintenance costs. For me, it's just an easy way to get a better, more enjoyable drive and, with the gain in economy, you're not out of pocket by as much as the difference in pricing would suggest ... worth trying for a few tanks.

Dave

[JOHNBMWM5]

Originally Posted by Daveyc

This is obviously a contentious topic, but I'd add one thought into the mix: don't be swayed by advertising hype. Instead, take an easy step and try if for yourself. Then use your head, your hands, feet and bum-on-seat to make up your own mind. If you don't experience any improvement, go back to bog standard.

In my experience over the years, my E46 M3 responded well to Shell Optimax (highest octane I could buy locally back then). The difference: smoother and and quicker throttle response and a useful bit of extra go at the upper end of the rev range (circa 6,500 to 8,200). No significant gain in power or torque lower down. But, for the smoothness and responsiveness alone, I went Optimax all the way. The difference wasn't a 'slap in the face' thing, but very obvious to any keen driver tuned into their car. Given the way I drove that car, my interest in economy was zero - never checked versus standard fuel.

More recently, E39 530d M Sport (tuned with hybrid blower, re-worked intake system, Eibach anti-roll bars, springs & AP Racing brakes - 300BHP and 470 ft/lbs). Tried both Shell V-Power diesel and BP Ultimate diesel. Both made a noticeable difference, the most obvious change being smoothness and consistency of pickup. There was more grunt in the 2,000 to 3.500 rev range and I consistently got 3-4 more mpg, especially on a long motorway run. Again, I wasn't especially into making a saving and I'd guess I was level-pegging on cost at best, or more likely a bit down, but the drive was improved to the extent that I would always look for one of these fuels first and take normal fuel only as a fall back.

As someone else mentioned - it's not just he extra cetanes, but the cleaning agents are worth taking into account if you care about the car. I learned the value of this recently when I had all my injectors replaced on the E39 - made an incredible difference.

One other thing - if you make the switch, you won't feel all the benefit until you've run through 2 or 3 tanks.

I guess some of you will be bike riders and here you can multiply the impact of premium fuel by a factor of two, just because bike engines are so much more highly tuned (180 BHP from 1300 cc 4-pot engine). I have a BMW K13s and it loves the premium fuels. I never find much difference in power, but there is a big difference in smoothness and consistency of throttle response and, if you ride a bike, you'll know how much that matters. One time, on a touring trip in France, I was forced to fill up with 95 octane fuel (on an older K1200 R Sport) - I got half a mile down the road, lost power and stalled. All my mates had to wait while I tried to restart the bike - got it going, but it ran like a dog for the next 100 miles. Never, ever, ever again in a fast bike ...

I'd guess none of this stuff makes a saving overall , unless you take the long view on keeping the system clean and reduced long-term maintenance costs. For me, it's just an easy way to get a better, more enjoyable drive and, with the gain in economy, you're not out of pocket by as much as the difference in pricing would suggest ... worth trying for a few tanks.

Dave

Dave you make the exact point I was trying to make, general everyday driving we would hardly notice the change, in your case with higher tuned engines being worked it would make a difference and you have proved it to yourself. My point is how often does the "average driver" ever get to use the top end of the rev range on UK roads?. Not much percentage wise I guess, so IMO why use the more expensive stuff. Each to there own.All my cars have not had a problem with smooth running, the ECU's adjust to the fuel put through them.

[dopper99]

Diesel cars dont rev as much as petrol so you dont use "top end of the rev range". As a result I find that in my car, the mid range performance is improved with premium fuels ie lower down the rev range for a diesel. Therefore you do notice it every day as you only need to squeeze the throttle and feel the response straight away.

In a petrol, then yes I would imagine you would need to rag it to feel the benefit from putting in premium stuff.

[MaestroAl]

Data or I call placebo

[JOHNBMWM5]

Originally Posted by dopper99

Diesel cars dont rev as much as petrol so you dont use "top end of the rev range". As a result I find that in my car, the mid range performance is improved with premium fuels ie lower down the rev range for a diesel. Therefore you do notice it every day as you only need to squeeze the throttle and feel the response straight away.

In a petrol, then yes I would imagine you would need to rag it to feel the benefit from putting in premium stuff.

My improvement will be one of these when it's run in.

http://www.diesel-performance.co.uk/...(2012-)_258-ps

STD fuel and loads more power.

[DieselRocket]

Originally Posted by johnbmw6

Dave you make the exact point I was trying to make, general everyday driving we would hardly notice the change, in your case with higher tuned engines being worked it would make a difference and you have proved it to yourself. My point is how often does the "average driver" ever get to use the top end of the rev range on UK roads?. Not much percentage wise I guess, so IMO why use the more expensive stuff. Each to there own.All my cars have not had a problem with smooth running, the ECU's adjust to the fuel put through them.

Yes, I agree. Unless you're driving something fairly ripped out, the benefits are more about better pickup and smoothness. I also agree with dropper99 though: I was certainly getting a useful amount of extra grunt in the low to mid rev range on my 530d.

Anyway, guess it's all down to the individual. The thing that makes me smile is knowing that the F30 330D M Sport I hope to see in December will fairly fly, even with chip fat in it

[M40WST]

I have had varied results when running BP/BP Ultimate with both Petrol and Diesel. When my F30 316d Arrives i intend on just running it on either Standard BP or Shell Fuel Save for at least a 1000 Miles or so to let the engine run in a bit and then maybe run a tank or two of Ultimate / VPower and see if it makes any differences. I reckon its likely to make it run smoother. Saying that though on the current car I have (An 06 Astra) Ultimate was lovely up until I had it serviced and had the engine flushed, after that the engine used to hesitate and end up using more fuel since then I have used normal BP or Shell and the engine has been fine ever since.