# What is the ONE known variable that we know is different between Euro 335d and US?



## AirBull (Jan 1, 2014)

It's the lower level of quality of the diesel here in the US! 

I think the main reason that the gas companies get away with this is politics, and to a lesser degree, a an uneducated diesel consumer market. In some states like IL and MN, you now have minimum B20 and B10 biodiesel which is nothing more than a subsidy to corn farmers, and does nothing to help the quality of the diesel. Why are politicians in bed against diesel? A couple of reasons.

First off, nearly everything we consume is delivered to our grocery and retail stores via what? Diesel powered trucks and locomotives. And this is why the Federal gas tax is higher on diesel than it is gasoline - that increased cost is passed on to the consumer who have but no choice to pay it. Gas companies in the US are no dummies - they will produce the crappiest minimum diesel grade that the local laws will allow them to get away with. :flipoff:

Fortunately in metropolitan Texas communities, there is a State law that mandates a minimum of 48 cetane diesel. https://www.tceq.texas.gov/airquality/mobilesource/txled/cleandiesel.html

But travel to the Hill Country just outside and to the West of Austin, and you're out to the Federal mins.

So what do we do about it? First off, pay attention to your local politicians and get your state like Texas, to mandate better diesel fuel. The Fed (and the current administration in particular,) are clearly in favor of Hybrid vehicles, when clean-diesel technology is staring everybody in the face as the much better alternative in terms of costs and performance. Don't even get me started on the expense of replacing Hybrid battery cells every 7 years or so.

In the mean time, what can we diesel owners do to protect our investment in the diesel vehicles that we all know and love? The same thing all the big truckers have been doing for years: Make sure the diesel we put in our tanks is from a good source, and then supplement it with additives. Every time I fill my 335d, i get a chuckle out of the "no additives" BMW wrote on the fuel filler cap. Obviously, we got the Euro spec filler cap! :doh:

Here's the basics:

1) we need to protect our expensive diesel injectors from the crappy, unreliable US spec diesel
2) perhaps more of an issue in Bosch CP4 fuel pumps in the VW/Audi's, but we need to add back the lubricty that we lost when we went to the ULSD (B5 actually helps this a lot, but again, the quality of our diesel is so intermittent)
and every bit as important I believe, and especially so in our US 335d's: 3) we need to increase the cetane. :drink:

_Is the widely varying Cetane level of U.S. diesel fuel, as compared to European diesel fuel, a problem? How does the engine compensate for this difference? Although a Cetane level of 51 will produce optimum performance in BMW Advanced Diesel models, the engine software is capable of adapting to various Cetane levels._http://www.bmwusanews.com/newsrelease.do;jsessionid=7987445C07EB25A0CB16A1F04CF4CCD5?&id=4&mid=

http://en.wikipedia.org/wiki/Cetane_number

I've first ran Stanadyne 20+ years ago, in a used a 1990 Jetta Wolfsburg diesel that had about 55k miles on it when we got to it, and long before ULSD. I like Stanadyne because they make diesel injectors, but DieselKleen has got some great stuff now as well in the gray bottle. It's relatively inexpensive and is available at nearly every Wal Mart - you just have no excuse not to use at least it in your 335d. It helps clean injectors, add's lubricity, and even says it boosts cetane. http://www.powerservice.com/dk/

But it's the cetane level that I think is most important to our 335d's, and it's contributing to our CBU issues. BMW says it's preferable to have at least 51 cetane diesel, but you won't find that at ANY pump in the US, so they say their DME will compensate. In my opinion, with the carbon build up issues in our NA 335d's, I charge that it's entirely compensating. With higher cetane, you get a better combustion in your cylinder that amongst other things, produces LESS soot, which equates to less carbon build up. On our TDI Passat and Touareg, perhaps that's not as big of a deal, but gauging the BMW US spec 335d's and the number of CBU issues, I'd say cetane levels are often wholly insufficient for our BMW higher performance oriented diesel N57 engines.

But don't take my word for it, do your own research. Ford has been offering cetane boost for years now, advocating less EGR soot build up as a benefit to running cetane boost All the cetane boosters advertise the same benefits - less diesel soot around the EGR, (which means less carbon being produced.) http://www.powerstrokediesel.com/docs/GetMoreForYourDieselFuelDollar.pdf

So what is the best cetane booster out there? I did a little research and read one article that says 2-EHN is the way to go. Look at the MSDS of all the different cetane boosters, and see how much 2-EHN they put in there. http://www.oilem.com/what-is-the-best-cetane-booster/

Some say alkyl nitrates can break down and oxidize in storage, but ArchOil and Amsoil are pretty reputable. 
_Most cetane improvers contain alkyl nitrates which break down readily to provide additional oxygen for better combustion. They also break down and oxidize fuel in storage. This generates organic particulates, water, and sludge - all of which degrade fuel quality. The result is often a fuel which no longer meets even minimum requirements. (*Because of these drawbacks, nitrate cetane improvers are not used in Fuel Magic.)_
http://www.superfuelsaver.com/Cetane%20Booster.html

If I could get ArchOil 6800 in the US, maybe I'd go for it. But you know who also makes a 2-EHN based cetane boost? Amsoil. http://www.amsoil.com/shop/by-product/fuel-additives/diesel/diesel-cetane-boost/

I got a case of 12 shipped and delivered in two business days, for $101. 2oz per 10g equates to a +7 cetane boost, which coupled with TxLED 48 min cetane, should put well into comfortable Euro levels of cetane, as BMW always intended our engines to have.

Do your own research and draw your own conclusions, I'm not trying to sell anything. I bought a case of Stanadyne 8oz bottles and use them to mix my additives together, ready for fill at the pump. I'm now running 4oz of Stanadyne Performance Formula, 2oz of Stanadyne Lubricity, and 2oz of Amsoil Cetane booster. http://www.thedieselstore.com/template/productOutput.php?VehNum=&partNum=ADD38564C#.U-_GImNmj0c

Maybe that's overkill I dunno :dunno: , especially with 48 min cetane and TxLED areas, so maybe I only need like 1oz of the cetane boost since the Stanadyne has some cetane booster in it. All I can say is, at least I will drive my 335d with confidence that it's getting the best diesel I can give it, and I'm not producing any more carbon than necessary. I'm sure this won't solve or eliminate the CBU issue entirely, but I know it's better than doing nothing. :thumbup:


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## Pierre Louis (Oct 23, 2011)

View attachment Effect of fuel cetane number on a premixed diesel combustion mode.pdf


So you are, uh, an automotive chemical engineer?

From here. *Effect of fuel cetane number on a premixed diesel combustion mode* is a paper that implies the DDE is more the culprit if combustion becomes ineffective:



> CONCLUSIONS
> 
> Based on the results of this research work, several conclusions can be made about operating premixed diesel combustion with fuels of differing cetane number in the range tested within this study.
> 
> ...


Its more obvious that BMW wants a cetane of 51 simply because that is what the engine is designed to do. However, lower cetane apparently is acceptable, and probably has nothing to do with carbon buildup or system failures. Experimenting with aftermarket additives flies in the face of how diesel producing companies tailor their additive package to the base stock, which may be very different between regions and even brands.

PL


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## F32Fleet (Jul 14, 2010)

The euro 335d did NOT have to meet our stricter emissions requirements. As a result we have new DDE which basically included the circuitry for the SCR system. 

I suspect that the US models require more frequent use of EGR. That would be the biggest difference. 


Fuel spec may be an issue but it's with regards to detergents keeping nozzles clean and internal deposits at a minimum and not necessarily lubricity.


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## AirBull (Jan 1, 2014)

Pierre Louis said:


> View attachment 458889
> 
> However, lower cetane apparently is acceptable, and probably has nothing to do with carbon buildup or system failures.
> 
> PL


"Apparently" and "probably" are not exactly compelling terms. There are a lot of people out there claiming the positive effects of increasing cetane amongst other things, decrease deposit (soot) buildup of EGR valves, (namely Ford for one.)

http://www.powerstrokediesel.com/docs/EGR_Valve_Info_Sheet.pdf


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## Pierre Louis (Oct 23, 2011)

AirBull said:


> "Apparently" and "probably" are not exactly compelling terms. There are a lot of people out there claiming the positive effects of increasing cetane amongst other things, decrease deposit (soot) buildup of EGR valves, (namely Ford for one.)
> 
> http://www.powerstrokediesel.com/docs/EGR_Valve_Info_Sheet.pdf


Sorry to disagree with you. There are lots of threads that discuss the scientific validity of various claims.

PL


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## anE934fun (May 10, 2008)

BMWTurboDzl said:


> The euro 335d did NOT have to meet our stricter emissions requirements. As a result we have new DDE which basically included the circuitry for the SCR system.
> 
> I suspect that the US models require more frequent use of EGR. That would be the biggest difference.
> 
> Fuel spec may be an issue but it's with regards to detergents keeping nozzles clean and internal deposits at a minimum *and not necessarily lubricity*.


You don't think lubricity of the fuel (lack thereof) impacts injector wear?


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## Geotrash (Dec 22, 2013)

Pierre Louis said:


> 4. For the operating condition and test fuels used within this study, matching combustion phasing (be it location of 50 per cent MFB, or more likely for production implementation the location of peak pressure) yields predictable combustion and gaseous emissions. Using cylinder pressure feed- back control to maintain combustion at a desired phasing position should enable more robust implementation of this premixed diesel combustion mode. Not only will the use of feedback control yield operation compliant with various fuels, but will also compensate for changes to other critical engine variables.


Thank you for the post, Pierre. Point #4 appears to hold the key. Measuring peak ICPs at a sampling rate fast enough for engine management electronics and injectors to respond has, I believe, been the chief barrier to having enough control of the combustion cycle to optimize emissions and fuel economy.

According to this article, it seems that first-generation ICP sensors for automobile engines hit the market in 2007, with Mercedes and Opel incorporating them into diesels after that time.

It's logical that BMW incorporates ICP sensors now as well, and it makes me wonder if later generations of these sensors with presumably greater accuracy and shorter response times could be the key to fewer problems with EGR and CBU in the latest BMW diesels on the market here in the US.

Cheers,
Dave


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## F32Fleet (Jul 14, 2010)

anE934fun said:


> You don't think lubricity of the fuel (lack thereof) impacts injector wear?


Not in our case. I suspect it's deposits either internal or at the nozzle. Bio is so prevalent these days I just don't see lubricity being an issue today. That's not to say there won't be instances where a particular station has bad batch of fuel. That's why people say frequent busy stations.


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## FredoinSF (Nov 29, 2009)

Is it me or is this thread a retread of everything I've been reading about for two years since I fist considered the X5d?
If the fuel were the only difference (and don't get me wrong, I know the fuel is different) why are the X5's not having the same issues as the 335d? Surely it's not that the X5's are not driven as much or that their owners are too dense / don't care enough to find this forum.

Yes the fuel in the US is different from Europe, but the real question is why does the 335d emissions system appear to be so problematic and why the darn thing appears to be subject to CBU. And BTW, Euro diesel are having their own issues with clogged particulate filters. That situation did not exist before the particulate filter, before that he cars just smoked and went for 500,000km with few mechanical concerns.


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## F32Fleet (Jul 14, 2010)

FredoinSF said:


> Is it me or is this thread a retread of everything I've been reading about for two years since I fist considered the X5d?
> If the fuel were the only difference (and don't get me wrong, I know the fuel is different) why are the X5's not having the same issues as the 335d? Surely it's not that the X5's are not driven as much or that their owners are too dense / don't care enough to find this forum.
> 
> Yes the fuel in the US is different from Europe, but the real question is why does the 335d emissions system appear to be so problematic and why the darn thing appears to be subject to CBU. And BTW, Euro diesel are having their own issues with clogged particulate filters. That situation did not exist before the particulate filter, before that he cars just smoked and went for 500,000km with few mechanical concerns.


Ya. It is a retread but hey at least we have the OP our opinion instead of saying "use the search button "
Lol


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