Supermarket fuel any good?

goldspanners

!!!!!! wrote: »

Yes which is why I only filled up once at each of the locations.
3 different Morrisons cause poor engine running (albeit all in the same region - common supply depot?) Never mentioned to the places I filled up mainly because I wasn't returning to them for about another 6 weeks. Seemed very non-MSE to make a special trip to tell them.
Tesco & Sainsbury cause a 5-7 drop in MPG. These fuels were used anywhere between Cambridge & Edinburgh so not a regional thing.

People can quote placebo, psychological or any other in vogue buzz word they like, but until they can prove categorically that there is absolutely no difference between the fuels and it is my driving style, I will continue to use other brands that I know work well with my vehicle. It is no skin off my nose, I can always find fuel as cheap, if not cheaper, than the ones that I boycott.

im still really curious about how it ran rough. was it idling erratically,was it not giving you as much power,was it not starting, and what did you do to correct the problem?
i regularly fill up a merc vito (which as anyone who has ever had or driven one will know) they have very sensitive fuel injection systems and i have had no trouble with poor running ever and on 120k miles and mostly filled on tesco diesel.

Conor_3

!!!!!! wrote: »

Ah the answer to everything when a valid response can not be thought of or something can not be disproved.

Ah the typical response when trying to justify the fact you've bought the marketspeak.

It has been disproved as I mentioned earlier on. Retro Ford did a proper test involving rolling roads producing torque and BHP graphs as well as road testing.

Conor_3

shandypants5 wrote: »

Is anyone who is reporting better mileage from better fuel actually logging the numbers on paper?

I logged mine. I can make Shell and BP diesel return as little as 52MPG and I can make Asda and Tesco diesel return as high as 59.7MPG.

Which proves its all marketbollox unless you own a performance car (200BHP+)where fuels like V-Power and Ultimate DO make a difference with a lot of that down to the fact the engine management can advance the timing to take advantage of the higher RON rating. For your average shopping trolley/family hack, they don't.

Conor_3

!!!!!! wrote: »

Ah the answer to everything when a valid response can not be thought of or something can not be disproved.

From EVO magazine article...

95 RON (Standard Unleaded)
"Supermarket 95-octane couldn't be included in the final results for the reason that supply is not consistent, so testing a batch would merely be a snap-shot. A spokesperson for ASDA, which sells unleaded at just 85p per litre, told us that it draws fuel from no fewer than seven suppliers, including Esso, Texaco and BP. Out of curiosity, we did test 95 from our local ASDA [Corby] and Tesco stores in Northampton and Wellingborough which, according to a spokesperson, might have been bio-ethanol as these branches do get it 'but not 100 per cent of the time', The ASDA fuel [which we were told was drawn from an Esso depot] was storming stuff and a match for BP 95."

High Octane results

Tesco 99

Price paid 93.9p/litre
Max power 212bhp @ 5500rpm
Max torque 242lb ft @ 2400-3500rpm

Highest octane rating of the pump fuels didn't quite give the top results. Massive gains over our sample of Tesco 95. Doesn't deliver like BP Ultimate low down but then gets ever closer before matching its power and staying stronger for longer, A fine result, and it's part bio-ethanol.

SHELL OPTIMAX

Price paid 95.9p/litre
Max power 209bhp @ 5500rpm
Max torque 242lb It @ 2500-2900rpm

Shows useful gains compared with Shell 95. Compared with other higher octane fuels, it's on a par with Tesco 99 low down but lacks its mid¬range [and that of BP Ultimate) with torque fading slightly earlier.

BP ULTIMATE

Price paid 100.9p/litre
Max power 212bhp @ 5300rpm
Max torque 252lb ft @ 2400-2500rpm

Level-pegged with Tesco 99 on peak bhp but significantly out-performed it and every other pump fuel in terms of torque [and even matched the race fuel into the mid-range!.

NOTE:
In order to benefit from the higher octane fuels, you need an engine with a compression ratio high enough to take it to the knock limit of 95 RON AND an engine management system that can adapt to take advantage.

System

goldspanners wrote: »

im still really curious about how it ran rough. was it idling erratically,was it not giving you as much power,was it not starting, and what did you do to correct the problem?

Lumpy running and reduced power. As already said, after having the same effect from 3 different locations, I stopped using it. No more lumpy running or low power.

One brand caused it 3 times from 3 different petrol stations. The cheapest option was to stop using that brand. No point in getting a mechanic involved at £xx per hour.

AdrianHi

Conor wrote: »

NOTE:
In order to benefit from the higher octane fuels, you need an engine with a compression ratio high enough to take it to the knock limit of 95 RON AND an engine management system that can adapt to take advantage.

Most modern petrol cars with engine control units (computers) controlling the engine fall into this category, 91 to 98 RON range is typical. The 102's etc. are a waste of money for nearly everyone and of questionable value considering the price on the high performance cars that can make use of it.

From another thread about diesel fuels which some people may or may not disagree with, results typical with people running 100bhp to 200bhp+ diesels:
Here are the requirements of EN590 the standard diesel fuel must meet in Europe:
http://en.wikipedia.org/wiki/EN_590
First on the list is the Cetane number which must be at least 51, no upper limit is given. There is more to measuring a diesel fuel quality than Cetane number alone, but this number is a measure of how well the fuel burns. A Cetane number above 55 gives no further benefit, Cetane number of diesel will vary by refinery, time of year, batch, colour of the underwear worn by the oil engineer etc. (OK the last one is not true ). When all else is equal (weather, driving route, driving habits etc.) a higher Cetane number fuel will result in better fuel economy, more power output and smoother running. The differences while often noticeable are never dramatic.
So guaranteed minimum (typically higher, especially in winter) Cetane numbers:
Regular diesel (super market and otherwise): 51
Shell regular diesel: 53 (once known as Shell Diesel Extra)
Shell V-Power diesel: 55
BP Ultimate Diesel: 55
Total Excellium: 53
Regular "51" diesel vs. BP Ultimate Diesel "55" and I measure a 5 to 7% improvement in fuel consumption.
Using an additive like Millers Diesel Sport 4 increases Cetane number by 4, so you always get 55+ regardless of which fuel used costs 2.5p per litre more and I measure the same 5-7% improvement.
Additives and premium fuels also have detergents and lubricants which have been shown to keep the engine cleaner over time.

For reasons I cannot find an explanation for I did used to measure a drop in economy *sometimes* on super market fuel, but with so many variables it's hard to blame that fact it's supermarket fuel for the drop.
These days I use Millers in what ever the cheapest regular diesel I can find.
Shell or discounted supermarket fuel (5p off per L with £50 shopping deals etc.) would be best value for money if you don't want to muck about with additives.

Conor_3

AdrianHi wrote: »

For reasons I cannot find an explanation for I did used to measure a drop in economy *sometimes* on super market fuel, but with so many variables it's hard to blame that fact it's supermarket fuel for the drop.

Which pretty much falls into line with my ability to get just short of 60MPG out of supermarket fuel or low 50's out of brand fuel with very minor changes to the driving style.

Most people would benefit from doing an economical and defensive driving course. Doesn't half improve the economy as well as reducing journey time which at first sounds the complete opposite of what it should do but once you do the course, it becomes clear why it does.

AdrianHi

Conor wrote: »

Most people would benefit from doing an economical and defensive driving course. Doesn't half improve the economy as well as reducing journey time which at first sounds the complete opposite of what it should do but once you do the course, it becomes clear why it does.

Reduced journey time = engine running for a shorter time = less fuel used I would guess.
Your getting very impressive MPG from, what was it a Mondeo TDi 140bhp?
Got any info. or quick tips from this economical and defensive driving course?

Conor_3

TDCi 130.

Yeah..
Here's a few:

1) When approaching roundabouts and traffic lights try to time it so that you don't come to a complete stop. If you keep a good gap from the person in front, you have control over your deceleration, not them. Remember time spent using engine braking is fuel free travelling whereas driving up to something to the point where you have to brake to stop isn't.
2) When exiting a motorway, let off the accelerator at the 300 yard markers and use engine braking to the end of the sliproad rather than driving down it. All that distance is completely free mileage. Same applies to roundabouts, junctions and traffic lights. Depending on the speed of the road, you can get 1/2 mile or more of fuel free motoring for every exit and roundabout.
3) Never coast in neutral. Modern engines are designed to completely cut off fuel on overrun (engine braking) whereas leaving them idling in neutral uses fuel.
4) Try and reduce the number of gearchanges.
5) Maintain speed up steepish hills, don't accelerate up them.
6) Smoothness and anticipation is very important. Driving along then reacting to events wastes fuel as you end up driving when you could've been using engine braking.

A good exercise is to create a route with urban and rural driving that has a few roundabouts on it. Drive it normally, noting the time it takes, the amount of gearchanges and the MPG you get. The end goal is to drive the same route with half the number of gearchanges in a quicker time with a lower MPG. A lot of the time is saved at roundabouts and traffic lights by entering them without stopping thus saving fuel used on idling and getting the vehicle moving again which most people have to do as well as regaining the lost speed from setting off from stationary.

There's a bit more than that if you want to take it to the n'th degree but you start getting into technical data, basically the graph of wind resistance vs. speed for the specific vehicle you drive and deciding which is an acceptable ratio whilst considering the impact on journey time. For the lorries I was doing it for, the speed hit was only 2KPH which reduced the ratio of resistance to speed significantly whilst having a minimal impact on the journey time but exceeding the speed limiter setting of 90KPH by 2KPH resulted in a dramatic increase of the ratio of wind resistance:speed for very little gain and one hell of an economy hit. It's not about pottering around everywhere at 45MPH by a long shot but finding a nice balance.

AdrianHi

Conor wrote: »

TDCi 130.

Yeah..
Here's a few:

1) When approaching roundabouts and traffic lights try to time it so that you don't come to a complete stop. If you keep a good gap from the person in front, you have control over your deceleration, not them. Remember time spent using engine braking is fuel free travelling whereas driving up to something to the point where you have to brake to stop isn't.
2) When exiting a motorway, let off the accelerator at the 300 yard markers and use engine braking to the end of the sliproad rather than driving down it. All that distance is completely free mileage. Same applies to roundabouts, junctions and traffic lights. Depending on the speed of the road, you can get 1/2 mile or more of fuel free motoring for every exit and roundabout.
3) Never coast in neutral. Modern engines are designed to completely cut off fuel on overrun (engine braking) whereas leaving them idling in neutral uses fuel.
4) Try and reduce the number of gearchanges.
5) Maintain speed up steepish hills, don't accelerate up them.
6) Smoothness and anticipation is very important. Driving along then reacting to events wastes fuel as you end up driving when you could've been using engine braking.

A good exercise is to create a route with urban and rural driving that has a few roundabouts on it. Drive it normally, noting the time it takes, the amount of gearchanges and the MPG you get. The end goal is to drive the same route with half the number of gearchanges in a quicker time with a lower MPG. A lot of the time is saved at roundabouts and traffic lights by entering them without stopping thus saving fuel used on idling and getting the vehicle moving again which most people have to do as well as regaining the lost speed from setting off from stationary.

There's a bit more than that if you want to take it to the n'th degree but you start getting into technical data, basically the graph of wind resistance vs. speed for the specific vehicle you drive and deciding which is an acceptable ratio whilst considering the impact on journey time. For the lorries I was doing it for, the speed hit was only 2KPH which reduced the ratio of resistance to speed significantly whilst having a minimal impact on the journey time but exceeding the speed limiter setting of 90KPH by 2KPH resulted in a dramatic increase of the ratio of wind resistance:speed for very little gain and one hell of an economy hit. It's not about pottering around everywhere at 45MPH by a long shot but finding a nice balance.

Some of the things listed here I have been doing for a while and they do make a noticeable difference, around 2mpg on a 47mpg diesel for me.
On the trip home and back to work since yesterday afternoon I've paid attention to more engine breaking and trying not to stop, timing arrival at junctions and roundabout to keep moving. Extracted another 1mpg from the car according to the OBC, which is good considering the drive is no less enjoyable, actually more enjoyable, less gear changing and effort :cool:
If I did more motorway miles I might get to the mid high 50's.