You didn't see what coming; that some people do not understand statistics?

Wouldn't say I don't understand statistics, a masters and final year of a PhD may suggest otherwise. Apologies for the slight speed reading induced oversight.

The zinc thing is slightly worrying. Interesting to see that cetane rating did raise slightly...think I may be sticking with Shell and millers or a 2-EHN cetane booster after all.

Thing with that article though, where benefits were evident they played them down somewhat.

You're not kidding! SLBOCLE result on EN590 totally glossed over.  

Note that in figure 1, a higher bar is worse than a lower one, but in figure 2 it's t'other way round.

 

Hmmm.

You're not kidding! SLBOCLE result on EN590 totally glossed over.  

Note that in figure 1, a higher bar is worse than a lower one, but in figure 2 it's t'other way round.

 

Hmmm.

Err - they are totally different test results from different tests - one is expressed in g and one in micrometers - so it's not entirely unusual that one would have high values as a pass and one as a failure.

The tiny gap between the error bars is expressed in the text as 'negligible' so hardly glossed over.

You're not kidding! SLBOCLE result on EN590 totally glossed over.  

Note that in figure 1, a higher bar is worse than a lower one, but in figure 2 it's t'other way round.

 

Hmmm.

 

Not that it's in any way relevant since 3500g is arbitrarily chosen as a conservative limit since there is no fuel specification written for it.

@ wja:

I wasn't suggesting that the scales were inappropriate to the tests, just that an 'at a glance' skim down the results graphs might make you miss the significance of the EN590 comparison in fig 2.

One result (fig 1) insignificant, one significant. Which gets more coverage?

 

@sepulchrave, it's a test of lubricity, so how is it irrelevant, pray?

Edited 4 January, 201610 yr by Wino

@sepulchrave, it's a test of lubricity, so how is it irrelevant, pray?

 

Because there is no official specification written for it, therefore the fuel additive packs are not designed for it. Nobody knows what an acceptable result looks like since no formal specification has ever been written.

 

It's a completely different type of test to the HFRR test, its results would be highly relevant for an engine oil, but not for a fuel.

Wouldn't say I don't understand statistics, a masters and final year of a PhD may suggest otherwise. Apologies for the slight speed reading induced oversight.

It wasn't meant personally; more an observation that most people probably would not understand that the effect of 2-smoke oil on South African diesel fuel lubricity is negligible and that the graphs show that.

Except the second graph which doesn't show that.

I agree, I once used supermarket diesel and found the lack of performance, I stick with Shell.

 

DB.

 

I do a lot of miles and fill up pretty much every week and log all my MPG etc. The only time I have ever noticed a difference with fuel is when using Texaco - I got virtually no smoke when booting it after cruising along at low revs. With any other fuel (Shell included) I get a cloud of black smoke when accelerating after a lot of relaxed driving. Can't understand why. Never noticed a lack of performance, poor MPG, rough running etc. with different fuels.

I do a lot of miles and fill up pretty much every week and log all my MPG etc. The only time I have ever noticed a difference with fuel is when using Texaco - I got virtually no smoke when booting it after cruising along at low revs. With any other fuel (Shell included) I get a cloud of black smoke when accelerating after a lot of relaxed driving. Can't understand why. Never noticed a lack of performance, poor MPG, rough running etc. with different fuels.

That is a weird one, would like to know what's making that difference with Texaco, suppose we'll never know.

It wasn't meant personally; more an observation that most people probably would not understand that the effect of 2-smoke oil on South African diesel fuel lubricity is negligible and that the graphs show that.

 

 

Except the second graph which doesn't show that.

It does. It shows no significant difference between the two sets of South African market diesel. There is a significant difference on the European low-sulphur diesel (3700+/-500) vs the European low-sulphur diesel plus two-stroke oil (4900+/-500) but not on the South African diesel. More interesting is the fact that the refinery diesel fails the arbitrary 3500g test limit with or without two stroke so it's the additives in the European and South African market diesel that make a REAL difference in lubricity, not the two stroke oil.

Now, if you look at the effect of the two stroke oil across the three fuels, if there really was a benefit you'd expect to see a consistent improvement across the board, but there isn't. It's just on the EN590 low sulphur diesel and it's a small significant difference (200g in 5000g) so 5%-ish vs nothing on the other fuels. And only on that one, unaccredited test method. There is no significant difference on the official test.

So do I think, on balance of probability, that the unaccredited test is wrong? Yes. But if you REALLY want to put two-stroke in your engine, go for it. It'll make f-all difference and you can probably convince yourself that it's REALLY beneficial.

Unimpressed by the scientific rigour of that study. I don't claim to want to put 2SO in any diesel cars, just pointing out that the data in that study isn't exactly clarifying things.

The author's reluctance to discuss that 'inconvenient' (EN590, the most relevant type for us) result is odd; immediately talking about measurement errors and weird stuff about paraffin?

Edited 4 January, 201610 yr by Wino

Unimpressed by the scientific rigour of that study. I don't claim to want to put 2SO in any diesel cars, just pointing out that the data in that study isn't exactly clarifying things.

The author's reluctance to discuss that 'inconvenient' (EN590) result is odd; immediately talking about measurement errors and weird stuff about paraffin?

I think they didn't have to include a non-standard test in the study. They did. It's thrown up what you describe as an inconvenient result. They didn't have to publish that result.

And that's patently not the full report, it's just an abstract for the layman.

Personally, I'd rather have the inconvenient result in some sort of replicated parametric study than an urban myth perpetrated by caravanners.

Do the same test with Petrol then, how come petrol cars aren't going BANG due to lack of fuel lubrication, they use high pressure common rail direct injection systems as well, and turbos, and sustain far higher combustion chamber temperatures than diesels.

 

It's NONSENSE, you need the detergents in the additive packs to keep the system clean, not zinc to clog the injectors.

 

None of this makes ANY sense at all, you want to put something in the fuel that your engine simply doesn't need because internet morons say so?

Sooo... Without adding fuel to fire... and reading 3 pages.

Should we all use cheap supermarket fuel and stick in some diesel additive such as millers or redex time to time? I did just buy a large bottle of redex for £5.00 at Halfords :P

Edited 4 January, 201610 yr by hutchysrs50

Sooo... Without adding fuel to fire... and reading 3 pages.

Should we all use cheap supermarket fuel and stick in some diesel additive such as millers or redex time to time? I did just buy a large bottle of redex for £5.00 at Halfords :P

Basically, yes! If you go the additive route then it should lessen any negative effects of supermarket fuel that have been experienced by some (although not all). Shell is more tried and tested for me and tends to be a fuel I can rely on, will put some v power in whenever I see any. In the meantime I will get through this bottle of millers and then try this neat 2-EHN stuff to ensure I'm optimising the burn. I'll do this whatever fuel I put in as apparently over 55 cetane makes bog all difference anyway?

Oh and whilst 2 stroke may help quieter running and less smoke, it doesn't appear to have any effect on lubrication or emissions, and if it's got zinc in it it may have a detrimental effect on the injectors specifically. Thanks for the input everyone.

Edited 5 January, 201610 yr by YellowCar

For those who might misunderstand or yell at me, here's a little timeline of my thoughts on this thread:

 

1. See OP, think "oh great, more snake oil"

2. Read the linked thread with all the typos and think "hmm, not convinced by that"

3. Come back later and see Chorlton's link to the paper, think " Great, there's some science that refutes the snake-oil!"

4. Glance at figure 1 in the study, think "oh, no difference with the 2-stroke, actually it makes lubricity slightly worse (though insignificantly so)"

5. Glance at figure 2 and mistakenly judge the EN590 result the wrong way and think "haha, even worse with that test!"

6. See YellowCar's comment about how they don't really give much coverage to the results that do favour the 2-stroke oil use, think " I didn't notice any of the those" so go back to the study to check

7. Spot the 'other-way-round' scale of figure 2, check text for their interpretation of this (EN590, positive effect) result from a test that they did "to further understand the lubricity effects" only to find they don't really seem to take away any further understanding at all, they dismiss it. 

8. Post my "You're not kidding!" reply to the thread.

9.Start to get flak from people who think I'm supporting the snake oil, just because I'm questioning the way the study's data is presented...

10. Knob-up and wrongly accuse Ken of being wrong in what he claimed- sorry Ken!

 

Morning everyone.

Edited 5 January, 201610 yr by Wino

The paper I quoted does has have some slightly questionable results from the SLBOCLE test, perhaps more tests should have been carried out (the number of tests was not stated) and more explanation was required by the Author.  However, the SLBOCLE test is not noted for its repeatability.

 

Taken from Ref [1] below....

 

'With every analytical test procedure, the information obtained can sometimes vary from one laboratory to the next.   Further, the information obtained can vary from one lab technician to the next in the same laboratory using the same analytical test equipment. 

 

Some companies report compensating for this variation of the SLBOCLE test by allowing a +/-300g range from the target weight.  The repeatability of the SLBOCLE is +/-900g and the reproducibility is +/-1500g.  A similar effect, although with a smaller range is noted for the HFRR test where the repeatability of the HFRR is +/-0.8mm (+/-80 micron) and the reproducibility is +/-0.136mm (+/-136 micron).'

 

The above errors on repeatability and reproducibility are also backed up in Table 1 of Ref [2] below.  The error bars shown on the graphs in the paper from my first post refer to repeatability (or standard error).

 

The SLBOCLE test requires more operator input than the more automated HFRR test, which is probably the source of error.

 

The results do show that the effect of adding two stroke to be small, certainly when compared to the addition of a properly formulated Lubricity Improver.  Additionally, all diesel in the EU can have up to 7% by volume of biodiesel, which further improves lubricity (see Ref 2).  So I don't really see the point of adding anything else such as two stroke. 

 

The remapped PD engine in my fabia has now done 155000 miles without any replacement parts and I rarely use 'special' fuel such as v-power, only using it if all the other pumps are busy.  I generally use fuel from Sainsburys and occasionally BP and Shell.  I have noticed no discernible differences either in performance, soot, engine noise or mpg.

 

REFERENCES

1. http://fpc1.com/test_reports/public/University/Lubricity/Biodiesel%20Lubricity.pdf

2. https://www.dieselnet.com/tech/fuel_diesel_lubricity.php

100ml per tankful should be sufficient. The cost of oil per tankfull must put you up towards Super Diesel prices. To the original poster, look up 2-EHN, which is what Millers, Rhino etc is - but they just dilute it with bulking agents such as kerosene. You can buy it pure off Ebay and add 60ml per tank.

approx 200-1 and I got 2 5l cans of comma mineral oil for less than 30 quid. Can't think what it equals but in the 2 tanks I've used without it the back of the car is black with carbon and there is a puf of smoke on start were now I've filled with 250ml of oil and 55l tesco diesel I get no smoke at all on start and it's quieter.

Also idles smoother too.

To me it's worth it.

Edited 6 January, 201610 yr by billy2981

The missus previously worked in a Tesco petrol station and use to chat to the fuel delivery drivers so I got her to ask them about the difference in fuel between brands.

They told her that when filling the tanker they sit in a queue with all the other different tankers i.e might be Shell in front, Esso behind with Asda behind that etc etc

They pull up to the same pumping station and connect the same hose to the tanker as all of the other brands use, so unless there is some behind doors secret switching of fuel supply/tank behind the scenes they are all using the same fuel.

I obviously cannot collaborate this but sounds like the sort of thing that would happen in rip-off britain, you are paying more for the brand name but actually getting the same thing just paying more for it!

I doubt there would be any interest from government departments in investigating as long as the tax money keeps pouring in.

If I was minted I would get some random samples tested, but I'm not so I won't

You are correct.

But

What you haven't mentioned is though it's the same fuel it's not the same mix of additive that goes in. Each tanker is filled at the same time as the extra additives go in depending on the retailer specifications.

So altho it's same fuel it's additives are different

Thanks again Chorlton, interesting reading, particularly the first reference and the positive impact of a small proportion of biodiesel in the mix.  

 

You say: "So I don't really see the point of adding anything else such as two stroke".

 

I agree, especially with the zinc revelation.  I think in practice, a lot of the perceived benefits of after-pump additives are a figment of the user's imagination, generated by their feeling of being more in control, because they, themselves are being 'active' in 'improving' their fuel. Not to mention having spent extra money that they need to justify to themselves.

The zinc was definitely one of the key turning points for me, I read that it was a case of 'nuff said.

You are correct.

But

What you haven't mentioned is though it's the same fuel it's not the same mix of additive that goes in. Each tanker is filled at the same time as the extra additives go in depending on the retailer specifications.

So altho it's same fuel it's additives are different

 

It was mentioned further back in this thread that the tanker driver adds an additive pack as the source fuel pumped into the tanker is the same, I don't know any Esso/BP/Shell tanker drivers so cannot verify that but it would seem to be the only possible way that the fuel gets it's additives (if it actually does!),

Yea I saw that it was on the next page after Ide replied.

I know it's not in my head that 2t oil makes a difference. I'll try it ill get the wife to fill the tank a few times and say pop some in on on or 2 and leave it out random.