[Toobad]

I've always run Red Ken on Tesco diesel simply because they have a filling station and I'm there every week anyway. Nothing wrong with that, it's not biodiesel and it has a cetane rating of 51 so it meets the Mercedes engine requirements for any warranty claims. As I was heading off to Scotland for a week I decided to put a tank of premium grade diesel through the 220d engine to see if I could notice any difference. I went up on Shell V-Power Diesel and came home on Morrisons supermarket diesel.

I did 486 miles on V-Power and got 49.5mpg @ £1.227/litre and would have cost £54.75
I did 486 miles on Morrisons and got 47.8mpg @ 1.157/litre and would have cost £53.47

So to do the journey on the V-Power actually cost me an extra £1.29 overall. Shell say their premium diesel has a cetane rating of 53 and contains 30% more detergents than their standard diesel. I couldn't detect any difference in engine performance. I may now do the occasional fill-up with V-Power just to keep the fuel lines and turbo free from crud but convenience will probably dictate that I'll mostly run on the cheaper Tesco stuff. The premium being charged locally for BP Ultimate Diesel is unlikely to see me on a BP forecourt any time soon. Even Dick Turpin wore a mask!

Please chip in with your own experiences and observations. There's a much stronger argument for running super unleaded in high performance petrol engines. Is that what you 43 people currently do?

 

[Draven]

I've always made a point, rightly or wrongly, of using premium fuel in my cars. Previous petrol cars were always fed Shell V-Power and my X5 was given V-Power Diesel.

Since owning the 43 it's only been given Shell V-Power (which is really helping with my Shell points accumulation) and I've no intention of changing that any time soon. I have absolutely no mathematical or scientific evidence to back up this behaviour other than obviously it makes my car go faster :grin2:

 

[gb93616]

I normally buy "premium" stuff, just because it says premium, but as soon as companies start using phrases like "Dynaflex Technology" I start to doubt the benefit. Then they start including numbers against their "facts" :-

Use new Shell V-Power Diesel with boosted DYNAFLEX technology for our best cleaning performance5.

FYI 5 is :-

5. New compared to previous Shell V-Power formulations. Boosted compared to Shell's regular diesel fuel for cleaning functionality. Helps to clean key fuel system components such as fuel injectors from the build up of performance robbing deposits. Actual effects and benefits may vary according to vehicle type, vehicle condition and driving style1. See shell.co.uk/dynaflex for more information about DYNAFLEX technology.

Oh, I just notice a "1" inside the "5" explanation.

1. Designed to help clean and protect key fuel system components such as intake valves and/or fuel injectors from the build-up of performance robbing deposits. Actual effects and benefits may vary according to vehicle type, vehicle condition and driving style1. See www.shell.co.uk/vpower for more information.

Oh please! There's a "1" inside "1"

I think buying these fuels makes "you" feel better than it makes the car feel better #justsaying..

I'm going for a lie-down6

6) I'm not really, I'm at work...

Graham

 

[Visa]

My uncle was head of world wide development at Exon and according to him the premium stuff is full of goodies that looks after your engine but you only get a benefit if you stick to the same brand and use it for at least 5 to 6 fill ups (2000 ish miles)

He always uses premium but I tend to run normal grades unless the car manufacturer tells me otherwise, because I'm tight

 

[Toobad]

For premium diesel I'm with Graham, most of it is what the marketing world refers to as "advertising puff". They are vague unquantifiable claims which just stop short of unlawful deception. All diesel sold here must meet a European Standard called EN590 and any tweaking to this base formulation is done with an additives package. I've no doubt the extra detergents are good for the engine but if you change your car regularly it just seems like you are subsidising the next owner. I think I get a greater feeling of satisfaction from filling up at the supermarket for 7p/litre less. I see the Mercedes Euro6-compliant engine can't be run on cheap biodiesel. I believe this green alternative animal/vegetable oil is created from rendered down puppies and kittens blended with chip fat so my ethics force me to stay with the fossil fuel.

 

[romk1n]

I did 486 miles on V-Power and got 49.5mpg @ £1.227/litre and would have cost £54.75
I did 486 miles on Morrisons and got 47.8mpg @ 1.157/litre and would have cost £53.47

wow cheap prices, didn't see any premium diesel cheaper than £1.35 vs £1.22-1.23 for regular.

 

[Mercedes.AMG]

I tried all the fancy fuels in my previous GLA45, never noticed it make any difference apart from the price of course.

 

[K44ent]

When I get my GLC43 I will be using Tesco Momentum Petrol, only because I have a Tesco filling station just down the road from me.

 

[AndrewB]

I run my 43 on Tesco momentum as that is higher octane and the 43 is designed for higher octane , I haven't tried the standard stuff so I don't know if it would be any different.

Andrew

 

[Toobad]

Tesco Momentum is a good choice. It has a 99 octane rating rather than the 98 rating of many other super unleaded suppliers. Increasing the octane means the fuel will resist explosion for longer thus allowing a denser mix to be ignited. Modern German engines can automatically adjust themselves to take advantage of a fuel with a higher octane rating and as a result can produce more horsepower when run on it. We run our motorbikes and TVR on Momentum because it also has a lower ethanol content than regular 95 RON unleaded. With more and more ethanol being added to fuel these days, it tends to go off far quicker. I find if I leave regular fuel in a tank for more than 3 months it starts to turn to gel in the fuel lines and injectors and the engine is a pig to start and will run like a dog. I always leave everything with a full tank of Momentum over the winter months. Shell V-power has slightly less ethanol and slightly more detergents added than the Tesco fuel but then this is also reflected in the price of the stuff.

 

[Philamg]

I use BP ultimate, only 97RON but no difference to when I have used shell v power of Tesco momentum.

 

[Toobad]

Yup, there will be no perceptible difference, only to your pocket. Your V6 will have optimised itself for 97RON and will be running as sweet as a nut. You would have to put it on a dyno to verify the extra horsepower 99RON would release as I doubt you would be able to sense it from the driver's seat in the course of normal driving. Your decision as to which fuel really comes down to a trade-off between convenience and the price you are willing to pay. If only everybody could have these First World problems

 

[Philamg]

Only convenience to me, shell v power and tesco momentum is cheaper down here than bp ultimate.

 

[ometofu]

hate me.. with 3 decades of owning different MB products from C/E/ML and E AMG, i always put the lowest octane . i can't tell the difference and never had engine issue. plus if it is 1s lower because the engine has to compensate, it is fine with me. horsepower is for bragging only to me.. you're more likely have transmission and electric issue before issue with the engine because you use low octane gasoline.