fuel lubricity data- with and without additives.

Tin Man said:

The fuel pump is very easy to get at on a CDI. Its right at the front of the crankshaft, staring at you. It costs $800 to replace (parts). I will ask the mechanic if this is a good idea to do at the next service.

Insurance? At least normal insurance is proven to pay. Additives? Not.

TM

Click to expand...

so- at least $1200 installed?

as far as increased lubricity paying for itself, see first post for improved lubricity proof, and links to the Bosch presentation for photos of pump component damage (CR too!) by lubricity deficient fuel.

tditom said:

so- at least $1200 installed?

as far as increased lubricity paying for itself, see first post for improved lubricity proof, and links to the Bosch presentation for photos of pump component damage (CR too!) by lubricity deficient fuel.

Click to expand...

We disagree as to what constitutes "proof" as can be understood in my posts and replies.

Oh, and I would just have the mechanic look at it, not replace it.

TM

you honestly don't see the direct benefit of the additive for lubricity with before and after measurements using the same fuel? what about the Spicer Test (also linked in first post)? All those additives that helped? (and I will also point out that some seemed to do nothing, or even make it worse!) point is, some work and some don't. go with one of those that has a demonstrable benefit.

tditom said:

you honestly don't see the direct benefit of the additive for lubricity with before and after measurements using the same fuel? what about the Spicer Test (also linked in first post)? All those additives that helped? (and I will also point out that some seemed to do nothing, or even make it worse!) point is, some work and some don't. go with one of those that has a demonstrable benefit.

Click to expand...

I trust the fuel companies to put the correct mixture in. The tests are with base fuel, which I don't buy. Adding an aftermarket fuel modifier would be just as likely to make it worse than improving things in a useful manner. The manufacturers of the additives have not been forthcoming with real data on their products nor have they shown any real effect on longevity. Its clear to me that additives have no proven preventive benefit.

Respectfully,

TM

i guess we're going to have to agree to disagree on the "correct mixture" . Bosch and all other FI mfr say they allow no more than 460 micron wear scar, ASTM says 520 (actually they allow 560 and then retest)

the last two Power Service test sheets (what is "real data" btw?) in post #1 show additized fuel (pump diesel). both fuel distributor additized fuels are well above the Bosch standard of 460. One is at 570 and one at 540 micron wear scar before adding DFS, and 395/410 respectively after PS is added. Spicer test shows the same result for several additives. biodiesel- my additive of choice- has consistently shown substantial benefit.

good luck.

There needs to be a study that shows:
1. Reproducibility/consistency of the test results
2. Results in real usage not just in a laboratory environment
3. Scope of effect i.e. does it prolong the life of a fuel pump from 750,000 miles to 800,000 miles or something different?
4. Reasoning used to arrive at the recommended standard: it is in the best interest of the pump manufacturers to set the standard too high. Are they looking for better profits in manufacturing pumps to a lesser standard? Are they trying to cover the variability range in assembled pump quality? Will Mercedes or VW go after them if there are multiple pump failures in some way or just fire them?

The ASTM meeting that determined the standard that differs from the pump manufacturers - how was that arrived at?

TM

Tin Man said:

I trust the fuel companies to put the correct mixture in.

Click to expand...

Bad idea.

Tin Man said:

...The ASTM meeting that determined the standard that differs from the pump manufacturers - how was that arrived at?

TM

Click to expand...

my answer to this comes from this excerpt from the ASTM meeting notes (see post #1 of this thread):

Here is a summary of ASTM's process for arriving at 520 micron max wear scar.

Quote:
Originally Posted by excerpt
...Revision of D 975-02 Specification for Diesel Fuel Oils to include a lubricity specification

PLEASE READ THIS NOTE AND THE SUPPORTING DOCUMENTS BEFORE VOTING.
...¸ Most members believe that we need to adopt a lubricity specification at ASTM to protect injection equipment from excessive wear.
...¸ The CRC Diesel Performance Group has committed to conduct a research program to provide additional supporting data to adjust this level if necessary, especially for the new high-pressure common-rail injection equipment.

Data and Discussion Supporting the Proposal: One technical supporting document for the proposed level is an SAE Technical Paper 2001-01-1928. An interpretation of the data in Table 5 by Ken Mitchell results in an average scar diameter of 517 microns for a passing pump rating of 3.4.

Since the lubricity correlation is not an exact science at this time, we also can find documents that conclude HFRR at 550 or HFRR at 500 microns. The proposed level of 520 microns based on the above document is a reasonable technical compromise to ensure proper protection for injection equipment.

It is worth noting that, although the correlation between SLBOCLE and HFRR is not close to perfect, most supporting documents and field data indicate that the proposed 520 micron HFRR level does not result in lower lubricity when compared to our previous proposal of 3,100 gram SLBOCLE level. In many cases it should provide better fuel lubricity.
...

Steps Beyond the current Proposal: This proposed specification will provide a starting point that would protect the injection equipment without creating harmful side effects and unnecessary cost to the fuel suppliers. ...

Click to expand...

I rest my case. The standard is clearly not one that has significant differences in real life save for the numerical ones.

TM

tditom, you're in a dead-end argument comparing apples to oranges with Tin Man.

You’re arguing a Bosch rotary injection pump which uses fuel for lubrication. Tin Man is quoting a CR equipped car. CR technology is rather immune to fuel lubricity.

Tin Man's anecdotal evidence with respect to his MB is invalid to VWs that use rotary injection pumps. He is also smart enough to know the difference but chose to quote the car with the CR technology to support his point. Even the pre-CR MB's have inline injection pumps that use engine oil for lubrication, so any comparison to any MB is invalid. He would have done better to use his NB as his example.

As time marches on and more CR technology comes into production, the lubricity issue will fade. When the GTL fuels come online there will be no lubricity issues. Any arguments about fuel lubricity are an interim issue, so enjoy the debate while you can. Time is going to render lubricity issues irrelevant.

BKmetz said:

.... CR technology is rather immune to fuel lubricity. ...

Click to expand...

not according to Bosch. look at slides 17&18 for CR system damage from poor fuel lubricity. maybe the more modern systems are less sensitive to it, but some certainly are. I don't see how you would generate those pressures without very tight tolerances. Some of the moving parts of the CR pump are only going to be seeing diesel fuel

The reason ULSD presents a lubricity issue at all is that sulphur is a lubricity enhancer, and was traditionally added to diesel fuel to this end. (Note that diesel will naturally have some sulphur content depending on the well it came from)

The introduction of ULSD for emissions purposes demands the introduction of other additives to preserve lubricity levels at the relevant standards. ASTM D975 requires a wear scar of 520micron, EN 590 (equivalent European standard) requires 460 microns. EN 590 allows the addition of fatty acid methyl ester (biodiesel) up to 5% without having to disclose this fact (known as blind blending); this biodiesel must meet EN 14214. The most common reason for this low level of blending is to add lubricity. It is also the reason European diesel engine manufacturers will allow B5 to be used in their engines. I am not familiar enough with the ASTM standard to know if it allows biodiesel addition in a similar fashion.

Companies will always do the bare minimum to meet standards, because this is invariably cheapest. So at best, the US fuel companies are going to meet the ASTM standard of 520 microns. This presumes they are fearful enough of being caught and scolded to even bother. Standards are only as good as the enforcement put behind them. Again, I don't know how good ASTM are at enforcing their standards: they might be very good, and have very strong punishments for transgressors, but they might not. If enforcement is poor, say goodbye to any hope of the fuel routinely being to spec.

The injection equipment manufacturers are going to demand a specification that prolongs the life of their equipment. Premature failures could be attributable to several factors, one of which is lubricity. But that's not always easy to prove when a pump fails, so the FIE manufacturer may have to foot the bill for a warranty claim that's caused by something out of their control. If they say that fuel has to be 460 micron hfrr, and the user puts in 520 micron, then they could justifiably say that it was operated outside of specification and get out of the warranty obligation.

I think it's a misnomer to say that CR systems don't need lubricity from the fuel. The injectors are still lubricated by the fuel and are a very high precision device with tiny tolerances. It may be that fewer components depend on fuel lubricity, but some still do.

tditom said:

not according to Bosch. look at slides 17&18 for CR system damage from poor fuel lubricity. maybe the more modern systems are less sensitive to it, but some certainly are. I don't see how you would generate those pressures without very tight tolerances. Some of the moving parts of the CR pump are only going to be seeing diesel fuel

Click to expand...

And they are designed to do so. If you can't buy/build/design a better one, why are you worried about it?
The fuel you can buy at the local pump will suffice. Drive more, worry less.

Bill

It would be very interesting to compare static timing clouds from various ALHs and see if there is any correlation with fuel.

40X40 said:

And they are designed to do so. If you can't buy/build/design a better one, why are you worried about it?
The fuel you can buy at the local pump will suffice. Drive more, worry less.

Bill

Click to expand...

why thanks for your helpful advice, Bill

i have every intention of buying a CR diesel in the future. I will just always insist on using fuel that the designers intended for us to use in it- not something that has had specifications compromised.

as far as local pump fuel sufficing- i don't see how you can come to that conclusion- but feel free to hold onto it.

BKmetz said:

CR technology is rather immune to fuel lubricity.

Click to expand...

I see the confusion. I guess I should have said 'more' instead of 'rather?' My context was in comparison to VE rotary injections pumps. Either way I never meant to say CR injection systems are 100% completely and totally immune to fuel lubricity, simply less so than a rotary injection system.

tditom said:

why thanks for your helpful advice, Bill

i have every intention of buying a CR diesel in the future. I will just always insist on using fuel that the designers intended for us to use in it- not something that has had specifications compromised.

as far as local pump fuel sufficing- i don't see how you can come to that conclusion- but feel free to hold onto it.

Click to expand...

Well gee whiz, Tom.

I plan on driving for several years more and also plan on several new cars that I hope will be diesel powered.

I do hope to buy fuel at the local fuel station.... it would really cramp my style if I had to get it anywhere else.

Maybe we can all just import some good GERMAN designed fuel for our german designed and mexican built cars? LOL

The food you eat, the clothes you wear and the medicine you take to save your life is the result of a series of COMPROMISES as is everything else in your life, your parents' lives and your childrens' lives.

Compromises in fuel specifications are small potatoes.



Bill

40X40 said:

...The food you eat, the clothes you wear and the medicine you take to save your life is the result of a series of COMPROMISES as is everything else in your life, your parents' lives and your childrens' lives.

Compromises in fuel specifications are small potatoes.



Bill

Click to expand...

couldn't agree more, Bill. but...errrr..... we ARE in a car forum discussion here...so....what is the relevance of your post?

tditom said:

couldn't agree more, Bill. but...errrr..... we ARE in a car forum discussion here...so....what is the relevance of your post?

Click to expand...

The relevance is that you condemned all commercially available fuels as bad for our cars simply because they are the result of COMPROMISE. I tried to point out that compromise is ubiquitous and is no cause for alarm.


We must not panic the newbies... It takes years to calm them back down, we once had a fellow sitting in his driveway trying to hold 3,000 rpm in park thinking he was following DBWs break-in sticky.... So, I am sure you will see why we must be careful what we post as it is sure to be taken out of context.

The fuel at the pump will be good enough for ME, and I will occasionally use fuel additives.

YMMV.


Bill

i'm not trying to scare anybody into doing anything. i am sharing my concern, which has caused me to take precautions. people can take it or leave it, but they need to do so knowing the facts.

tditom said:

I'm not trying to scare anybody into doing anything. i am sharing my concern, which has caused me to take precautions. people can take it or leave it, but they need to do so knowing the facts.

Click to expand...

Unfortunately, you have little in the way of facts, or scientific logic, to back up your cautious behavior. I am merely pointing out the paucity of information, including from the pump manufacturers. You may be satisfied with what data is available, I am not.

Ironically, we seem to trust the fuel manufacturers enough to put their fuel into our cars, but somehow we cannot trust how much additive they use. I would recommend using a major supplier for diesel, since they have the most at stake and will more than likely overdo their use of additives to protect their market share. Fleet owners of expensive diesel machinery may have quite an influence on their livelihood should pump failures begin to occur. I personally don't trust some suppliers over others and feel that the major oil companies have more resources to taylor their additive package to the available fuel.

Somehow, aftermarket additives seem to have no "side effects" with daily preventive use. Historically, there have been cases of adverse effects with certain additives to fuel or oil. This is why most car manufacturers routinely recommend against them except for specific purposes like fuel gelling etc. You even acknowledged that in one "study" the most popular additive of all actually decreased lubricity. This point was also in one of my posts.

I agree with others that find this issue relatively unimportant, especially with the idea that a compromise was established. It annoys me how authoritative some seem to be, however, in claiming it to be unwise to not use aftermarket additive with every fill. Somehow the additive makers get more credit than the car manufacturers and fuel suppliers - why trust one group over another - they all have a financial stake, and the additive makers want you to believe their magic elixirs are better than sliced bread! Car manufacturers tend to be very cautious with issues such as engine oil specs etc. and are known to change recommendations retroactively if they find a problem. Even GM recommends specific brands of gasoline due to their quality. So if you base your mistrust on past behaviors, I would tend to trust Mercedes if not VW for proper advice over some guy on the Internet or some snake oil sales pitch.

My 2002 NB TDI went 156,000 miles and its fuel pump (and rest of the motor) was working perfectly when I sold it. No additives either. No fouling of intake and only 2 glow plugs needed to be replaced the entire time. The CDI made that wonderful car sit in the driveway.

TM

Here's the logical progression that should have happened if aftermarket additives were necessary, at least for precautions:

1. Fuel suppliers and pump manufacturers get together and petition ASTM for suitable standards.
2. ASTM decides on best overall standard but cautions that not enough data exists as to true endpoints such as pump failures, not just lab benchmark data.
3. ASTM comes up with preliminary or temporary recommendation to use aftermarket additive as a precaution until more is known.
4. Known principles of additive technology allow car manufacturers to specify which brands and types are recommended and a list is available at the dealer.

This didn't happen.

There are a number of reasons why, not the least of which may be that different pre-consumer additives will mix with different base fuel and different aftermarket products unpredictably. ASTM doesn't even have enough information, I surmise, to even recommend aftermarket stuff. They apparently could only agree on an endpoint of scar diameter under laboratory conditions and did not determine how such an endpoint can even be achieved other than by the fuel makers.

TM

Here's the logical progression that should have happened if aftermarket additives were necessary, at least for precautions:

1. Fuel suppliers and pump manufacturers get together and petition ASTM for suitable standards.
2. ASTM decides on best overall standard but cautions that not enough data exists as to true endpoints such as pump failures, not just lab benchmark data.
3. ASTM comes up with preliminary or temporary recommendation to use aftermarket additive as a precaution until more is known.
4. Known principles of additive technology allow car manufacturers to specify which brands and types are recommended and a list is available at the dealer.

This didn't happen.

Click to expand...

ASTM will not concern themselves with recommending additives or specific components of a fuel. They will specify parameters that the fuel must conform to such as cetane, calorific value, lubricity, etc. and they will specify the methods used to test for these properties.

The testing methods are going to be standardised laboratory methods so that different fuels can be compared on a level playing field. The limits are chosen in consultation with the relevant stakeholders based on their opinion of what is acceptable. As has already been shown, this is going to be a compromise between the demands of the different stakeholders, and it may not be the ideal solution.

At the end of the day, the ASTM (or any other standards agency) will issue a specification, and it's up to the stakeholders to comply with it as they see fit. They will not get involved in endorsement of specific products, nor will they give direction on how the specification should be met. The manufacturers of fuel will submit a fuel formula for testing, and if it passes all the tests listed in ASTM D975, then it can be sold as diesel fuel in the US.

ttt
http://forums.tdiclub.com/showthread.php?t=268198

You have got to read tditom's link above. I can't wait to see the comments after all the additive naysayers read the report about HPFP wear due to poor lubricity US-based diesel fuels and what many of us have thought all along and took the appropriate action. It's OK to admit you may have been wrong about additive importance since the 2009 engines have come out and that those of us using OL, PS, Stanadyne, etc. made a wise investment and continue to do so every fill-up A few bucks per tank is a very small price to pay when you compare it to an $8-10K repair bill

Please sticky this post. MANDATORY reading!

Link to how biodiesel improves lubricity.

www.biodiesel.org/pdf_files/fuelfactsheets/Lubricity.PDF

Great read..thanks knapp! Just reinforces what many of us already knew and how important lubricity is in the new engines and why additives are so important if Bio is unaccessible.

securityguy said:

Great read..thanks knapp! Just reinforces what many of us already knew and how important lubricity is in the new engines and why additives are so important if Bio is unaccessible.

Click to expand...

Know what? Truth is you don't know and neither do I. I guess you just keep taking your vitamins, herbs, fruits and nuts everyday and remember that small piece of chocolate before bedtime..............and the aspirin tablet and all will be well.................................................or just eat healthily (purchase quality diesel) and be done with it.

For every product out there someone has found a reason you have to have it otherwise no one would buy it. First create a potential problem............than make a cure............and you'll become rich. How easy is that.

The drug companies have been doing this for years........

Happy New Year everyone.......
Dan

GTIDan said:

Know what? Truth is you don't know and neither do I.
...

just eat healthily (purchase quality diesel) and be done with it.
...

Click to expand...

hi dan-
i'm not sure if you are disputing the fact that adequate lubricity is needed, or that biodiesel provides adequate lubricity. both of these are proven facts

As far as quality diesel taken care of the problem, that is exactly what we are trying to do- additize the subpar diesel available at the US pumps so it is adequate fuel . if biodiesel is not available for this, then a proven additive should be used.