Are all diesel’s equal?

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Rank Amatuer

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I do notice an improvement in mpg when I use Shell premium fuel in my FL2 compared with BP’s premium, which in turn is better than supermarket stuff.

Is there any hard and fast evidence regarding which brand of diesel is best a) for your pocket and b) for your engine?
 
There are only six (I think) working refineries in the UK at present, so in general terms, yes all diesel is equal. What is not certain is the amount, type and quality of the additives that each supplier then adds. :)
 
I do notice an improvement in mpg when I use Shell premium fuel in my FL2 compared with BP’s premium, which in turn is better than supermarket stuff.

Is there any hard and fast evidence regarding which brand of diesel is best a) for your pocket and b) for your engine?

I've been testing my works van since @1988smithy and I were discussing real world results and achievements for our petrol vehicles.
Vehicle is a 2018 Peugeot Partner van, no idea of engine size but it goes like a rocket.
4 tanks of fuel;

#1) 47.8mpg on regular diesel
#2) 50.1mpg on first tank of Esso premium
#3) 52.4mpg on second tank of Esso premium
#4) 53.7mpg on the third tank of Esso premium

So the results are in that the Esso premium diesel has reduced consumption and from day to day driving it does feel a touch more responsive, I'm 2/3 way through the 5th tank and will report back but as for difference between actual brands and their premium, I have no idea.
 
As I understand it; internal combustion engines are basically "heat" engines. The more heat (within reason) it can develop the more energy you will get out of it. Heat is measured in calories and calorific value is proportional to the weight of the fuel. Diesels run on "heavy oil" and so get more energy output than a petrol engine for the same volume of fuel hence they get more mpg. So how many mpg you get is less dependant on the brand and more dependant on the weight of the fuel. Maybe that esso premium is slightly heavier than ordinary diesel and so you get a few more mpg because you need to use the loud pedal less aggressively? Just a thought.
 
There is a huge difference in price between supermarket fuel and say BP. I would need to get about 6mpg better consumption to make it worthwhile using BP and my average figures don't show any difference between the two in terms of fuel consumption. What the cheaper fuel is doing to my engine I can't say. Generally, I put one tank of super premium in per 4 tanks of supermarket fuel.

Col
 
There is a huge difference in price between supermarket fuel and say BP. I would need to get about 6mpg better consumption to make it worthwhile using BP and my average figures don't show any difference between the two in terms of fuel consumption. What the cheaper fuel is doing to my engine I can't say. Generally, I put one tank of super premium in per 4 tanks of supermarket fuel.

Col

Screw the supermarket junk, I run my little Pug on super unleaded and nothing less, better in every way, when the Discovery is back up and running it too will get premium diesel, no point worrying about MPGs with my tyres and lift etc, so long as it's not terrible then it's good enough, or it'll get a V8 :D
 
I find out of all fuels, diesel and petrol, Shell Vpower is the best. When I had my Astra SRi, I got on average 4mpg more than tescos and Morrisons. I havent had the chance to run decent fuel in my 200tdi yet, just a tank of Esso. But when I put Vpower diesel in my old 19J, it would run miles better, and I tended to get an extra 2mpg on average.
 
Screw the supermarket junk, I run my little Pug on super unleaded and nothing less, better in every way.

I have the same opinion regarding unleaded in my RRC. I'm always dubious of SM fuels in an older vehicle as those engines don't have the computerised ignition timing to cope with variations in octane quality.
 
Modern LRs aside, these trucks were designed to be used in 3rd world countries where you need a tea strainer to get the twigs and gravel out.
OK, that is a slight exaggeration, but diesels up to and including the TD5 were designed to run happily on relatively poor quality fuel. They will not have an issue with SM fuels, all of which conform to strict standards. You might get a few more mpg with the posh stuff, but not enough to offset the additional cost. A hotter burn might reduce exhaust carbon and give you a cleaner EGR, but only marginally so and this is probably balanced by a slightly increased risk of head gasket failure, particularly if coupled to an aggressive remap. Overall, if you want to maximise the life of the engine, then IMHO posh fuel has minimal benefit compared to regular oil changes with good quality oil.
I use SM fuel and have no issues.
 
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