posh diesle vs common as much diesle

[jacksun1987]

Ive been putting the posh stuff in my 95 xantia 1.9 td. The total excerlince one. What ever its called at 145.9 i think. The normal stuff cost 137.9.
I havernt nticed any differnce. Ive only put 30 pund in. Same as what i normally put in.
I remenber putting it in my 406 1.9 diesle. It seem to rev higher. And it did seem to accerate a bit quicker. But thats bout it.
In my xantia havernt noticed that much differnce. When i put it in the 406. It was near the bottom on the light. Mabye thats why i noticed it a bit more.
In the xantia the needle was 1 notice from the resve line.

Have you lot noticed any differnce. Is it a con.
Or does it only make a differnce in new deisles hdis

[Northern_Mike]

145.9!

I have a TD, it has a Bosch pump. I run it on 90p litre veg from Costco. It runs better than it does on diesel.

In my experience, I've never noticed any difference on the rare occasion I've had to put the posh stuff in.

[CitroJim]

Diesel is diesel is diesel. There's no difference. I could go into a lengthy explanation involving diesel combustion theory but I won't for fear of boring you to sleep...

Zzzzzzzzz!

Just be assured that is the case... Cetane ratings mean bugger all in reality.

[Xaccers]

The only one I know that produces a minor improvement over normal diesel is v-power, but then they mix in their version of redex and some synthetic diesel.
Cassy runs best on veg from Costco though, KTC seems to be a bit better than the Pride stuff.

[Northern_Mike]

The only one I know that produces a minor improvement over normal diesel is v-power, but then they mix in their version of redex and some synthetic diesel.
Cassy runs best on veg from Costco though, KTC seems to be a bit better than the Pride stuff.

Yes, I find the KTC stuff better as well.

Just out of interest, what do you use to pour it in Xac?

I made a couple of these...



It's the KTC lid, with a hole made in it, and a Wickes toilet overflow spigot (£2.70) screwed through it. I just screw it on, pour it in. So much easier than messing about with funnels.

Of course, the Pride lids are slightly different, so I had to make two, one with each sort of lid.

[Xaccers]

Ooo going to make me one of those!
I use a funnel and a short bungee cord. With Cassy being an estate, I flip up the gutter access flap, hook the bungee around that, through the funnel handle and pour it in.
Think I'll be off to B&Q after work tomorrow though, that'd be much cleaner, but what do you do about air locks or does it just collapse the plastic veg container?

[Northern_Mike]

Well, it collapses the container, but as our recycling people take the containers away in the boxes, and I don't reuse them, I just use my penknife to make a hole in the top (bottom) of the container as it's emptying, then it empties faster.

[DickieG]

Cetane rating does make a difference as it improves combustion, I used to be able to easily buy Millers Diesel Additive and found that it both improved performance and starting on believe it or not a C15D to the extent that it payed for itself. With Millers special lotion it started instantly on the first turn of the key, without it would churn over a couple of cycles then fire up and after comparing consumption with/without Millers defiantly made a difference. With veg oil the cetane rating is lower than standard diesel so whilst an engine may appear to run better on veg the honest reality is likely to be somewhat different.

[Xaccers]

Well, it collapses the container, but as our recycling people take the containers away in the boxes, and I don't reuse them, I just use my penknife to make a hole in the top (bottom) of the container as it's emptying, then it empties faster.

That's what I used to do with the metal drums, rest the drum on the back of a dining room chair, then stab it with a screwdriver.

[CitroJim]

Cetane rating does make a difference as it improves combustion.

Yes, but only on a cold engine. The cetane rating is a measure of how keen the fuel is to go bang spontaneously at a lowish temperature and the higher the cetane rating the more keen it is so it follows that a fuel with a high rating will lead to easier starting. Once the engine is running and hot the cetane rating is totally and utterly irrelevant.

So yes, your observations are totally valid Richard. In fact DERV is formulated to have a higher cetane rating in winter to ease starting and I reckon your economy improvements seen were simply due to better starting and cold running due to less diesel being wasted in churning over and initial poor running. Every puff of grey or black smoke is effectively wasted diesel and it can be some miles-worth if properly combusted.

Some posh DERV I believe has some sort of injector cleaning additive. Clearly this can help enormously if they're a bit gummy and varnished...

Generally though you'd may as well save a few bob by using Tesco Fantastic Value diesel rather than Shell Super Carlos Fandango and chuck in a squirt of diesel additive every now and again to help keep the fuel system nice and clean...

[Xaccers]

Since 2001 the minimum cetane number of derv has been 51.
V-power has a cetane number up to 55.
The higher the cetane number, the more readily the fuel will burn so the longer the fuel has to burn through the compression cycle, so the more energy you get from it.

[CitroJim]

The higher the cetane number, the more readily the fuel will burn so the longer the fuel has to burn through the compression cycle, so the more energy you get from it.

Sorry Xac, I don't entirely agree. Come round for a cuppa and I'll explain diesel combustion

There is some mileage in the argument on a very modern diesel that can adjust timing on the fly to take advantage but it's minimal. It's all to do with ignition delay..

I guess I'd better put some words together to explain...

[DickieG]

I hear what you say Jim but the facts are that when using Millers diesel additive consumption improved by at least 2-3 mpg over a period of several years summer and winter using C15D's and Xantia TD's including my SX and VSX which were only used for long runs of 80+ miles, quite how a slight improvement in starting can account for the difference in consumption under those circumstances is beyond me. I carried out many tests of with/without Millers and every time I used it it made the same difference, if I still had a local supplier I'd use it now.

[CitroJim]

It just doesn't stand up to conventional diesel combustion theory as I understand (or mis-understand) it Richard...

Diesels generally run happily on anything containing enough weakly-bonded hydrogen and carbon atoms. A diesel would run on tarmac given you could heat it enough to make it runny enough to inject. Ships do, by and large... Bunker fuel is not unlike tarmac really...

My best theory over why these additives work is they must somehow improve atomisation of the injector spray perhaps either by keeping everything spotless or somehow modifying the chemical properties of the fuel to make it atomise better. Atomisation is the key to good diesel efficiency and performance.

You should be able to test the theory by running a tankful with the additive and then a tankful without. If the cleanliness theory is correct you should see no difference on the first additive-free tankful and then a slow deterioration with subsequent additive-free tankfulks as the injectors become a little mucky...

[DickieG]

Whatever the theory Jim Millers Deiselclean = an additional 2-3 mpg when used and 2-3 lower when not from tank to tank, forget theories and use real world experience. You're spending too much time reading and not enough doing real world testing