Grades of diesel...... your thoughts

[Eshrules]

Ok, i've heard that the grade of diesel differs quite a bit between different fuel stations.

at the moment i use tescos, never had any complaints as far as unleaded went as they use a higher grade i've been told, but the diesel doesnt seem to be up to scratch, im not getting the mpg i ought to and i've seen something called super diesel i think, on BP pumps, whats the difference between the standard diesel BP sell, their super diesel and the diesel at tescos? or is there not an ounce of difference? LOL your thoughts anybody...

[bluetwo]

don't know anything about the technical differences. The sainsburys/BP stuff seems slightly less pokey than others (maybe i imagine it?), but then i don't buy the premium stuff anywhere.

My gut feel is there is probably little difference between any of them, apart from the price and the marketing. Don't the main retailers all swap around anyway? i think most of the refinaries are joint owned.

Anyone run on Bio Diesel?

[Eshrules]

don't know anything about the technical differences. The sainsburys/BP stuff seems slightly less pokey than others (maybe i imagine it?), but then i don't buy the premium stuff anywhere.

My gut feel is there is probably little difference between any of them, apart from the price and the marketing. Don't the main retailers all swap around anyway? i think most of the refinaries are joint owned.

Anyone run on Bio Diesel?

less pokey? whats that then?

huweth runs his on biodiesel i think, hes got a passat estate me thinks

[bluetwo]

....less power on acceleration, worse fuel economy.


I'd be interested in trying the biodiesel, not too convinced it is produced to any consistent standard though (not that you can buy readily). Don't really want to risk shagging up the injector pumps on those long chain fatty acids...

[ian]

i know there is high octaine petrol and that makes a difference in your car but have never heard of it in a diesel before, try hitting the shell and BP web sites and see if you can find some info on there.
or you could email a few companies and see what they say.

let me know your findings mate, you have got me interested now !!


ian

[Huweth]

Yep, I am running 42% Biodiesel at the moment. (Just upped the mix from 30%). Can't really tell if there's any difference in MPG or power, but the engine is certainly smoother and quieter than with pure diesel. Exhaust smells better too. I'll probably increase to a higher percentage when the weather gets warmer. My supplier still has 100% Bio in his 2006 VW Caravelle.

The different fuel stations do supply different fuels. Supermarkets buy theirs from the big fuel companies. I've forgotten who supplies each of them, but the info is on the web.

Here's something for you. When you put "City Diesel" in your car, it is blended with BioDiesel to 5%. Not all places sell this, but it's quite common. The reason it's done is because Ultra Low Sulphur Diesel (ULSD, 15ppm sulphur), which is now the only diesel for sale at the pumps, has worse lubricity than the old Low Sulphur Diesel (LSD, 500 ppm sulphur). In short, the Biodiesel makes the ULSD run better in the car.

Legally, any type of Diesel sold in the UK can contain up to 5% Biodiesel and no-one has to declare it at the pump. You are probably already running on part BioDiesel. In France, it is a legal requirement that ALL Diesel contains 5% Biodiesel.
This means that all the Diesels in France and the UK can and do use Biodiesel some or all of the time.

As for the performance value's of Diesels, here's a bit of basic science.
While Petrol has an Octane rating, which prevents the fuel igniting early, allowing tighter timing, Diesel has a Cetane rating. The cetane rating shows how quickly/easily the Diesel will explode when it is made too. The higher the cetane, the more responsive the fuel will make the engine.

Now think about the different fuels again.
Normal Diesel contains more energy (BTU's) than Biodiesel, hence gives better performance and MPG. Biodiesel has a higher Cetane than normal Diesel, so explodes more readily. Therefore, a low concentration of BioDiesel in the ULSD will help it to explode and lubricate the engine better, giving you more response and MPG. At higher concentrations of BioDiesel, you get even more response, but less MPG and power due to the lower energy in the Bio.
It's a tradeoff between Cetane, BTU's, and lubricity.

I like driving about with a quieter, smoother engine that is only adding 58% of the CO2 to the atmosphere that it would be if it were on ULSD.

Sorry for the long post, I'm currently 'Preaching' Biodiesel to anyone who will listen. Most run away...

[mkpp786]

Ok, i've heard that the grade of diesel differs quite a bit between different fuel stations.

at the moment i use tescos, never had any complaints as far as unleaded went as they use a higher grade i've been told, but the diesel doesnt seem to be up to scratch, im not getting the mpg i ought to and i've seen something called super diesel i think, on BP pumps, whats the difference between the standard diesel BP sell, their super diesel and the diesel at tescos? or is there not an ounce of difference? LOL your thoughts anybody...

I dont know about the differences in grades etc. But from personal experience, after using BP, tescos, Sainsburys, Texaco and few other dreadfull stations, i have found that shell has been the best for me.

For me it gives the best MPG and for some reason it feels a lot more better when driving.. if that makes sense

[devonutopia]

I use the cheapest, and just add Millers additive to the tank. Currently on a tank of Tesco basic diesel. Needle moved off "full" when past 100 miles, and it currently tells me it's got another 450 miles to go. This is with a 45 litre tank too. I tried BP Ultimate Diesel (I think this is the stuff referred to by the OP) and I got worse economy, more smoke, and generally the car didn't feel as pokey.

Now, my car was remapped on basic diesel too, which "might" play a part in what fuel it likes to run on - however, as a general rule I just pick the cheapest stuff, and it runs the same on tesco, sainsburys, Shell, BP, Texaco.

[bluetwo]

good thread.

Huweth, i'll listen. Where do you get your fuel? Is it a buy it in bulk/need a tank set up? I've looked in to the process and the principles but haven't managed to find it very readily available, and home brew isn't where i'm at at the moment.

[NicholasP]

ive tried tescos stuff and BP Ultimate and I really notice the difference with BP ultimate..car is more responsive. Going to try Shell's stuff tomorrow...