Premium Diesel Fuels?

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A4Ultra

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Hey guys, I wanted to get everyone’s opinion on premium diesel fuels. I don’t know if it’s been mentioned before but I specifically bring it up because I contacted Audi UK a few times mentioning this and they said not to use any fuels which contain additives etc? I specified shell fuel and even the fuel system cleansing they offer at many of their branches but they said not to go for it unless I was advised by the service department. I found this strange considering I assumed they would want to push their own services?



Bought my A4 Ultra TDI with 41k on the clock on LL servicing and want it to last so I’m switching over to annual oil changes and also thus why I’m considering v power diesel/similar stuff? I always use basic supermarket fuels but thought that a premium fuel every couple of tanks or every so often would be good? But if they’re saying not to, I don’t want to damage my car.



Anyone got any experience on these fuels and more importantly, if they’re safe to use? I always thought they were a treat for your motor but maybe I’m wrong????
 
Apart from the supposed detergents added to premium diesels, they may also have Cetane boosters. The higher the cetane number, the shorter the ignition delay and more complete the burn. Most diesel fuel has a cetane number around 51-52. Optimum is around 60.

I'd avoid Shell V-power diesel. It has the detergents, it has a decently high cetane number, but because of it's synthetically derived content, it is almost 10% less energy dense than regular fuel, so mpg isn't great.

If you want to get premium fuel on the cheap, buy regular diesel and add Millers diesel additive. It's about £50 for a 5L can that'll do about 100 tankfuls for the equivalent of 2p a litre of fuel.
 
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^last time I looked into it (about 3 years ago) it was 54. Clean burn but less hydrocarbon to burn per litre.
 
Someone on an honest John thread shared the technical data sheets for comparison of a number of diesel types. Shell's standard fuel save diesel gad a higher Cetane number than the V-power stuff.

In Shell's own promotional info for V-power it tells you that about half tge blend is diesel synthetically derived from natural gas and has a lower average C number (average hydrocarbon chain length) than refined diesel. Theirs is marginally cleaner but is less calorific.

In my own experiences with a string of VAG 1.9, 1.4 and 2.0TDIs bought new, I've always had 10% less mpg with V-power than most other diesels. Generally had best mpg from BP and Sainsbury, but not enough better to pay the extra as BP stations are very expensive around Tyne and Wear. I generally fill at Costco or Morrisons and add 50ml of Millers to a tank.
 
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Thanks for the info guys. Did a short 120 mile round trip today and it's the first time I've used shell fuel as I always use supermarket diesel since it's closer.

Route was different today with lots of stop start and it's 26 degrees so the A/C was blowing hard. But the car showed 68-69mpg for quite a considerable distance. I am astounded. This is normal Shell diesel btw (fuel save). Is the difference really that much!?!!?

If it's not a one off I'm tempted to make the permanent switch. Very tempted to try a tank of V power diesel now too! (Will keep in mind the additives as well you mentioned)

Just to confirm though, is the V-power diesel safe since Audi say not to go near it?
 
A4Ultra said:
Thanks for the info guys. Did a short 120 mile round trip today and it's the first time I've used shell fuel as I always use supermarket diesel since it's closer.

Route was different today with lots of stop start and it's 26 degrees so the A/C was blowing hard. But the car showed 68-69mpg for quite a considerable distance. I am astounded. This is normal Shell diesel btw (fuel save). Is the difference really that much!?!!?

If it's not a one off I'm tempted to make the permanent switch. Very tempted to try a tank of V power diesel now too! (Will keep in mind the additives as well you mentioned)

Just to confirm though, is the V-power diesel safe since Audi say not to go near it?
Click to expand...

Just to put your improved mpg into context, what would it normally be with other fuels for a trip like that? Unseasonably warm weather helps diesel mpg a great deal - warm humid air expands a lot in diesel combustion.

Not sure why Audi don't recommend V-power. A while back when VAG TDIs moved to CR from PD (around 2009), they were advising not to use diesel with a high biodiesel content. Naybe they're categorising similarly, although V-power is derived from natural gas.
 
A4Ultra said:
Thanks for the info guys. Did a short 120 mile round trip today and it's the first time I've used shell fuel as I always use supermarket diesel since it's closer.

Route was different today with lots of stop start and it's 26 degrees so the A/C was blowing hard. But the car showed 68-69mpg for quite a considerable distance. I am astounded. This is normal Shell diesel btw (fuel save). Is the difference really that much!?!!?

If it's not a one off I'm tempted to make the permanent switch. Very tempted to try a tank of V power diesel now too! (Will keep in mind the additives as well you mentioned)
Click to expand...

Unfortunately unless you could do a back to back comparison with supermarket fuel in the same conditions (almost impossible) you wouldn't know if this was a real gain or not. Personally I think its more to do with the conditions and not the fuel. I never believe that top price branded fuel is much different to supermarket, it can only be additives as the base fuel is the same.
 
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V-power diesel is a total waste of money. The whole point in having a diesel is for fuel economy...so Shell develop a diesel fuel that's less calorific than regular diesel, to give worse mpg and no discernable performance gains unless your car's internals/injectors are gummed up and filthy (V-power will help clean them out).

Similar to those fools who fill their RON95 optimised petrol cars with RON98/99 fuel and think they're going to gain 40ps in the process because tge only difference between a Golf GTI and a Golf R is the sticker on the fuel flap telling you to fill your R with RON98, right?
 
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Thanks for the help chaps.

Just curious as to how this works. As I mentioned, bought the A4 with 41k on the clock and LL servicing so I imagine that an injector clean etc would be good? If you were to use it or similar (how often should it be used)?
 
Unless the last owner was filling up with red diesel from rusty old building site tanks, modern pumped diesel is very clean, and should keep your injectors clean too.

If you feel the need, maybe treat the car to V-power every 5 tanks for cleaning additives. Chances are it won't need it. Or run an injector cleaning product through a full tank.

You'll only really know if your injectors are clogged if the car isn't performing as expected. I generally fill with Costco or Morissons, although Costco is getting expensive because it beats its local Adsa price by a penny a litre and my Morissons is 3p a litre cheaper than the Asda at the Metrocentre that Costco undercuts.
 
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Gazwould said:
2-EHN .

https://www.ebay.co.uk/itm/Hydra-Fu...331195?hash=item3f59e83a7b:g:-iEAAOSwqu1avw~L
Click to expand...

This is the first time I’ve heard of 2EHN, I’ve been doing some reading and from my new understanding it’s basically a cetane enhancer which should apparently allow for the diesel to burn hotter and faster but produce more NOX.

Anyhow, I’ve used Asda fuel for 10’s of thousands of miles and have never had an issue. I just go for the cheapest stuff with diesels.

So does 2EHN make a considerable difference to MPG, and does it cause any long term damage?

I asked a chemical engineer friend today the above and he laughed and claimed it’s pointless.
 
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I was given 5L of 2- EHN and yes it's a bonifide Cetane number improver so I use it .

In my 1.9 tdi AVF I used JASO FB , 2 Stroke oil to which it halved my mot smoke opacity test
( several years of results ).
 
Gazwould said:
I was given 5L of 2- EHN and yes it's a bonifide Cetane number improver so I use it .

In my 1.9 tdi AVF I used JASO FB , 2 Stroke oil to which it halved my mot smoke opacity test
( several years of results ).
Click to expand...

I suppose your vehicle is an older diesel without a DPF filter so it can’t be relevant for long term DPF damage however, did you notice any discernible MPG gain?
 
smog c6 said:
This is the first time I’ve heard of 2EHN, I’ve been doing some reading and from my new understanding it’s basically a cetane enhancer which should apparently allow for the diesel to burn hotter and faster but produce more NOX.

Anyhow, I’ve used Asda fuel for 10’s of thousands of miles and have never had an issue. I just go for the cheapest stuff with diesels.

So does 2EHN make a considerable difference to MPG, and does it cause any long term damage?

I asked a chemical engineer friend today the above and he laughed and claimed it’s pointless.
Click to expand...

Your mate should sharpen up on his Kinetics & Equilibria and Thermodynamics as a chemical engineer.

The EHN increases the volatility of the diesel slightly, allowing a more complete burn in the ignition cycle as it starts marginally earlier and burns quicker. More complete burn = more mpg, smoother running and less soot generated. It's not snake oil.

I get about 5% more mpg and you can feel when you've forgotten to dose your tank after filling.
 
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Lol, you’ve given a great excuse to give him a snipe.

I meant he said it’s pointless using it, not that it doesn’t have an effect, we had a small conversation and he rambled on about stuff I didn’t really understand (My background is medical).
 
Thanks guys, after doing a bit more digging around also, it seems it may only serve some benefit to have V power diesel if you run it for 3 tanks as then it makes a difference I've read.

Doesn't seem worth it now, maybe in the future who knows.

Will continue to use shell basic diesel though and switch it with supermarket fuels every so often - starting to like the shell stuff a bit :)
 
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