Diesel Fuel Performance

T

TonyS

Well-Known Member
Joined
23 Feb 2003
Messages
616
Location
Southampton, UK
Visit site
I have been very surpried to find that changing to Shell diesel from the diesel I bought at Tesco (Esso?). That the fuel consumption reduced on my diesel Honda CRV from 45 MPG to 51.5 (over 1000 miles of mixed driving). I also met someone else who confirmed the same so I e-mailed Honest John at the Telegraph and he confirmed that he had found the same, saying it was due to the cetane value (whatever that is) and better detergent in Shell. Will this improvement also happen in the VP 2030 on my boat? Have other Forumites the same experience?
 
I have observed a similar increase in performance, but this happened with the fuel I bought at Tesco's. So it might be that the fuel characteristics have been changed by many suppliers. I am not sure I'd notice the difference on my boat engine though... I always hope to use wind!
 
There was a thread on the Moody Owners' forum about this in relation to red diesel (more properly, "Gas Oil") last week. I posted a link from it to Jet/Conoco's UK fuel specs. Gas oil's cetane rating spec is unquestionably inferior to that of road diesel. In the case of my own engine, the obvious differences are that I need more pre-heat for starting and I quickly collect a film of soot over the transom (whereas the exhaust is clean if I use road diesel). More important, that suggests to me that we're more likely to get carbon build-up on the valves and the scraper rings, and more soot in the lube oil if we use gas oil. Also, gas oil contains about 40 times more sulphur than road diesel, which leads, I think, to much more rapid acidic contamination of the lube oil, and that causes, amongst other things, corrosive pitting of the main and big-end bearing surfaces. Having said all that, the economics are probably in favour of using red diesel unless you use only a few gallons a year.
http://moodyowners.org.uk/infoboard/messages/5/2159.html?1126044585
 
Thanks very much - some of us do use only a few gallons a year!

For example, I have an ancient MD2 of 15 hp installed in a 37ft gaff cutter. I reckon to use the engine for three hours each weekend, to get on and off the mooring which is at the top (narrow and crowded) end of a small estuary.

I probably use between ten and twenty gallons a season.

I want the engine to last, and I dislike scrubbing oily smuts off the topsides under the counter. If I used Shell's, or BP's, or Sainsburys', finest road diesel, and the engine became easier to start, had less acid in the luboil, and smoked much less, I reckon I might be on a winner.

Am I right?
 
That's interesting. For the last year or so I've taken to using diesel from a garage in my 1GM, as I only get through a half dozen gallons a year at the outside, and then only if it is a windless summer.
The point is that it starts much more readily than ever before, to the extent that I now disregard the starting advice, i.e. set the throttle to maximum, and usually start it after a couple of turns in tickover. I had put that down to all the recent mods and repairs post diesel bug, and water in the fuel, which is why I started using garage fuel (and Soltron) in the first place. I never really considered that (a) marina diesel could be so much worse or (b) a 1GM7 would notice the difference. Maybe it it is the fuel after all, but I'm not going back to the red rubbish to find out!
 
One of the characteristics which differentiate diesel fuels is the density ... diesel engines really run on mass (weight) and not volume. The density can vary from 0.82 to 0.845 for diesel, and up to 0.860 for gasoil. That is a possible range of almost 5%. Cetane number is another issue. Cetane is the diesel equivalent of octane. Higher CN is better for a diesel. Shell Optimax, and BP ultimate have higher CN than the minimum requirement which is 51 for Euro IV diesel.

Unfortunately, it is impossible to know the density or cetane number of the fuel sold in a particular garage - Shell, for instance will only refine the diesel bought in the NWest of the UK. Around London, it will probably come from BP Coryton, and in Southampton, from Esso Fawley. Perhaps the density should be declared at the pump?

Supermarket brands are likely to be inferior, as they will have a lower cost additive package than the majors, and arevlilely to go for a minimum density.

Having said all that, I tend to buy my diesel from the supermarket, as it is generally cheaper.
 
Thank you. Very helpful. So Shell Optimax and BP Ultimate are the same stuff, and they really are different to regular grade stuff.

The old boat is switching to BP Ultimate (nearest garage!) from now on, as I've just done a quick calculation of the cost of a bottle of additive vs using good road diesel, and on our consumption there is no contest!
 
[ QUOTE ]
Thank you. Very helpful. So Shell Optimax and BP Ultimate are the same stuff, and they really are different to regular grade stuff.

[/ QUOTE ]Yes same refinery depending on where you are.
[ QUOTE ]
The old boat is switching to BP Ultimate (nearest garage!) from now on, as I've just done a quick calculation of the cost of a bottle of additive vs using good road diesel, and on our consumption there is no contest!

[/ QUOTE ]Be careful! many older engines will not run on ULS diesel , well at least not for very long as the pumps and injectors rely on the higher Sulphur content as a lubricant, there can also be a problem with "rubber" seals. I would check with your engine manufacturer giving the age and serial number of the engine and pump etc before changing from red diesel which is much higher in Sulphur content than any road diesel.

This was a major issue with the road transport operators, haulers and bus companies etc when the govt pushed the oil companies into producing ULS (Ultra Low Sulphur) diesel for road use.

If you go the MBM red diesel forum you will find a few threads on the subject.
----------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
 
Ooooh errr!

Thanks. Suspect 37 year old injectors and pumps come into that category!

Rats! Another Cunning Plan bites the dust!
 
Re: Ooooh errr!

Maybe maybe not although I would suspect they would fall in the "can't use ULS" type same as mine on my Bukh DV24 but always worth checking cos a replacement pump and injectors would be the equivalent of what? a couple of thousand gallons of diesel (difference in cost between red and white)
----------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
 
Re: Shell Optimax is petrol

[ QUOTE ]
So Shell Optimax and BP Ultimate are the same stuff, and they really are different to regular grade stuff.

[/ QUOTE ]
Shell Optimax is 98 Octane Unleaded Petrol. BP Ultimate can be either Unleaded Petrol or Diesel.
 
Re: Shell Optimax is petrol

You are quite right .. Shell's "expensive" diesel grade is called "Diesel Extra". That is what I was referring to - the higher cost grade of diesel.

BP use the same brand name for the "higher performance" grades of both gasoline & diesel, whereas Shell use different names.

Given the number of people who use the wrong pump in BP garages, I think Shell may have got the marketing right, by using different names.
 
Re: Thanks very much - some of us do use only a few gallons a year!

I think it proves you get what you pay for. The cost of removing the sulphur from diesel to make it ultra low sulphur is partly meet by a tax concession long eaten away now by the high cost of crude oil.
On the point of LSD not having the lubricating sulphur, shell and and I am sure others as well add an anti scuff additive and each tank of fuel is checked that it will not damage your engine before it leaves the refinery.
So if we get forced to use the LSD road fuel in our boats we will not have to worry about it affecting our engines just our wallets.
Trevor
 
Re: Thanks very much - some of us do use only a few gallons a year!

[ QUOTE ]
On the point of LSD not having the lubricating sulphur, shell and and I am sure others as well add an anti scuff additive and each tank of fuel is checked that it will not damage your engine before it leaves the refinery.
So if we get forced to use the LSD road fuel in our boats we will not have to worry about it affecting our engines just our wallets.
Trevor

[/ QUOTE ]Unfortunately they don't add additional lubricants or anti scuff additives. Modern pumps and injectors were designed not to need the sulphur / lubrication but unfortunately you will have to have your pump and injectors overhauled / converted to use the ULS if you have an "older" engine or you will have to but the additives separately. I believe it is mainly a case of changing some seals and a couple of other modifications for the pumps and a replacement job for the injectors.
----------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
 
Re: Diesel Fuel Performance .... PeteMcK and others .....

Where did you get that info from .... ???? M<ust have been from some amateur fuel guru ????

Sorry but get it right please ....

Road Diesel as you call it is 50ppm (0,05%) Sulphur, soon to reduce to 35ppm.
Red Diesel is 0.2% Sulphur ....

Cetane value yes is less in Red but not enough to really worry about in the average clonking boat engine.

Second who said Tesco is Esso Diesel ?? In fact it went from a Blending Co. that is one of my clients to another who is DEFINITELY NOT Esso ... I will not name them - as I am held by Commercial Confidentiality ...

As to grade / quality .... a) stop mixing words about ULSD (Road Diesel / City Diesel) and Red ..... they are different animals .... for completely different engines / jobs ...
 
Re: Thanks very much - some of us do use only a few gallons a year!

No ... as ULSD is less lubricant quality and has to supplemented by ester based lubricity agents. Your old MD is designed for Red and that is what you should use till no longer available.
Once it is no longer available - company's such as mine will be injecting various additives into ULSD to make it better for old clonking engines such as mine and yours ....
 
Diesel supplies ....

If anyone thinks that UK refinerys cater for full reqt's of UK market - they are mistaken ....

A significant %age of fuel used in UK is produced outside UK and shipped in for blending to UK spec. That is Diesel, Gasoil and Gasoline.

How do I know .... I happen to inspect for quality and Quantity ......

So forget all that marketing hype about one co. better than another, one area gets from ex refinery etc. etc.

Tsk Tsk !!
 
Re: Thanks very much - some of us do use only a few gallons a year!

<<shell and and I am sure others as well add an anti scuff additive and each tank of fuel is checked that it will not damage your engine before it leaves the refinery>>

Very interesting - so I shall be out of a job then ?? NO refinery adds additives to road spec that I know off ... unless own market ...

Because fuels are blended so much now with different sourced products - the additives are added by companies such as mine when ships load at port for shipment out LONG after refinery and before blending.

The reason Refinerys generally do not add additives - is they do not knopw where a batch will go ... export, local or other ... each having its different spec's to meet ... NO refinery is going to pay for Lubricity or CFPP agent unless on a steady priced contract ....
 
Additives ARE used ... who said not ????

Sorry but EU and International Specs .... EN590 for example mean that additives ARE added for various reasons .... >

Lubricity
CFPP
Cloud
Cetane

to name but a few ....
 
You must log in or register to reply here.

Share this page

Top