[babaikram]

Are all premium brands of diesel the same? Some independent stations do sell premium diesels as well. Are they worth it?

[JLR1969]

Premium diesel is not the same as premium petrol, it won't increase power but does have cleaning properties so may be useful every now and again

[JOHNBMWM5]

Originally Posted by babaikram

Are all premium brands of diesel the same? Some independent stations do sell premium diesels as well. Are they worth it?

BP supply Sainsburys, the very same Diesel.
High powered cars like top fuel, diesels do not.

[HighlandPete]

Originally Posted by JLR1969

Premium diesel is not the same as premium petrol, it won't increase power but does have cleaning properties so may be useful every now and again

Don't forget the cetane rating is typically higher in premium diesel. Cetane does change the combustion burn. From my reading of technical papers, cetane benefits in several ways. A more complete combustion, can release more energy from the fuel, lower combustion knock, less smoke, less oil contamination at source. Also improved fuel consumption.

Personally observed premium diesel best improves mpg in steady state driving at low to medium loads. Such as cruising at 60 - 70mph.

[Pottsy]

20,000 miles on normal diesel: 48.8 mpg, then...
30,000 miles on Shell V-power: 47.1 mpg.

[JOHNBMWM5]

Originally Posted by Pottsy

20,000 miles on normal diesel: 48.8 mpg, then...
30,000 miles on Shell V-power: 47.1 mpg.

says it all.

[HighlandPete]

Originally Posted by Pottsy

20,000 miles on normal diesel: 48.8 mpg, then...
30,000 miles on Shell V-power: 47.1 mpg.

Much as I'd expect, a slight drop off, as other users have found.

You do know Shell V-power being less dense, has a lower unit energy than regular diesel?

Being a blend of petroleum based diesel and GTL (Gas to Liquid) synthetic diesel, it is much cleaner, so emissions will be lower, with less soot. But you can't expect the mpg, as the energy just isn't there in V-power diesel.

[Pottsy]

HP,

Yep, I am aware of the effects of GTL, and would expect a tiny drop in mpg. Those figures are slightly skewed by the use of winter tyres that have been on and off during the periods (17" wheels save around 3.8 mpg over the staggered 18"), but I continue with the premium diesel on the hope that tipping all those detergents down the engine will be a long term insurance policy. And it is a hope! I posted those figures just in case anyone thought they'd get better mpg by using premium diesel, which would be a duff premise.

[HighlandPete]

Originally Posted by Pottsy

HP,

Yep, I am aware of the effects of GTL, and would expect a tiny drop in mpg. Those figures are slightly skewed by the use of winter tyres that have been on and off during the periods (17" wheels save around 3.8 mpg over the staggered 18"), but I continue with the premium diesel on the hope that tipping all those detergents down the engine will be a long term insurance policy. And it is a hope! I posted those figures just in case anyone thought they'd get better mpg by using premium diesel, which would be a duff premise.

Same cleaner running reason as I ran BP Ultimate in my 330d. Certainly less muck in the EGR lines, than I expected, when I had a look.

Most who try premium fuels are looking for immediate advantages, mpg being the one measure most are seeing as value for money. Not many are looking to longevity, reduced oil contamination, or less maintenance, at higher mileage.

Let's be honest, how many users are thinking about injector life and efficiency after say 100,000 miles. (Car may be long gone by that mileage). May be saying, "I run on Tesco's cheapest and can't let the difference". Not ever thinking the high cost bill for new/refurbished injectors at 100,000 miles or so, could be related.

How many drivers consider using a cleaner running diesel, when they drive short trips, simply to keep the engine cleaner inside? Or driving in urban settings, they may be producing less emissions with the premium diesel?

[Pottsy]

Indeed. And to help, I'm even now looking for a square set of 18" wheels (much like on yours). The staggered wheels have a silly tyre size on the rear, meaning it's hugely expensive runflats, or hugely expensive runflats. Non-runflat 245's all round will help handling, economy, noise, ride and so on.

150k, here I come!