40 cetane diesel

I have an X5d on order so I've been scouting around my local area for premium diesel, I found that most were rated 40 cetane. I'm a little worry about taking out-of-town trips and having to hunt down a 45 cetane pump in area I'm not familiar with. Have anyone once in awhile pump 40 cetane diesel and did you see any immediate afffect using it?

Why are you concerned? All of the documentation with our X5d makes zero reference to cetane requirement. The only requirements BMW has for the diesel used is that it is ULSD and has a max bio-diesel content of 5%.

I have a 35d on order too and I'm not familiar with having to purchase diesel either. I searched around some and from what I can tell, stations aren't required to post the cetane rating. How did you determine the cetane rating of the diesel from your various stations?

During my searching, I found a reference to the following documents:

http://www.tceq.state.tx.us/implemen...eandiesel.html
http://www.tceq.state.tx.us/assets/p.../txled_q&a.pdf

I live in Austin. It appears that quite a few Texas counties are required to have a cetane rating of at least 48. Austin's county, Travis, is included in the list, so I should be able to purchase diesel anywhere in the area and I'll be good, right?

However, like you said, how in the heck do I know what diesel to buy when traveling? The anecdotal evidence that I see from most posters on the web show that letters from retailers only "guarantee" a cetane rating of 40, but "much of it is higher". Oh that helps.

Here are some posts to various forums that I found quotes from letters from gas companies (except HEB, that was just opinions):

Exxon/Mobile (2009): http://forums.tdiclub.com/showthread.php?t=249770
Shell/Chevron (2010): http://www.bimmerfest.com/forums/sho....php?p=5051598
Valero (2009): http://oldforums.tdiclub.com/showthread.php?t=247254
HEB (2010): http://forums.tdiclub.com/showthread.php?t=258365

Originally Posted by jpeytonii

Why are you concerned? All of the documentation with our X5d makes zero reference to cetane requirement. The only requirements BMW has for the diesel used is that it is ULSD and has a max bio-diesel content of 5%.

At a Press Conference, BMW made the following comments:

-------------------------------------------------------------

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...

... How will you cope with the wide variety in Cetane ratings in ULSD fuels across the US, Canada, Mexico?

The systems will adjust up to certain ranges but buying fuel from a clean and reliable source is very important.
------------------------------------------------------------

So perhaps he is concerned because he'd like "optimum performance."

jpeytonii, you're right! I had just assumed that the X5d would requires premuim diesel. I looked at the manual again and it does not say anything about premium cetane rating.

barbja, thanks for the info, the stations that I went to did had cetane rating on it, I had just assumed that it's standard to post it like octane rating...I guess its not.

I have owned four VW Diesels and the manual states for the use of a diesel fuel with a minumum of 45 cetane. I always tried to find a BP Station with BP Premier Diesel.

My only point was that BMW does not specify a cetane requirement and that you are not going to dmage your vehicle by running a 40 cetane diesel as long as it is ULSD and non-biodiesel (B5 or lower). Personally I always buy name brand premium fuels (Shell, BP, etc.) if available.

Here in Illinois the bigger concern is the biodiesel content. There is a tax incentive to sell B11 or higher so many stations sell that rather than petro diesel. Also the cetane rating is rarely displayed.

1. There is no BMW requirement to use "premium diesel" in the documents provided with your vehicle. These are the ONLY documents that 'count'.

2. Any statements to the contrary, by BMW in other types of communications are (a) not binding and (b) possibly motivated by other than 'what is essential for your car.

3.l There is a LARGE push by refiners and fuel companies to prey on consumers fears with the same kind of marketing that they use with 'super' ratings on gas. Indeed many of the 'premium diesels' do not even specific cetane, but are just regular diesel with a few proprietary additives with unproven benefit. Buying "premium" diesel is no guarantee you are getting any specific cetane rating (although each state has their own laws on labeling)

OP, I would not worry about cetane issues at all. I've never checked to see what the cetane rating is at the stations I use, and I have not noticed any performance issues whatsoever. The only thing I refrain from doing is to fill up at truck stops along the highway, just because I heard (and therefor am not sure of) that they might carry some really lower grade diesel (agricultural) that should not be used in passenger vehicles. Again, I'm not sure of the validity of this claim, but regular stations carrying regular diesel fuel are ubiquitous enough, and they all carry diesel that should be just fine for the X5d.

Thanks for the information guys. It put my mind at ease, now the hard part is waiting till May for my X5d.

Originally Posted by Marwan

OP, I would not worry about cetane issues at all. I've never checked to see what the cetane rating is at the stations I use, and I have not noticed any performance issues whatsoever. The only thing I refrain from doing is to fill up at truck stops along the highway, just because I heard (and therefor am not sure of) that they might carry some really lower grade diesel (agricultural) that should not be used in passenger vehicles. Again, I'm not sure of the validity of this claim, but regular stations carrying regular diesel fuel are ubiquitous enough, and they all carry diesel that should be just fine for the X5d.

I would check your source regarding the "lower grade diesel" being sold at highway truck stops. First of all agricultural, or more accurately "non-road use" diesel, is not necessarily lower grade (though it could be). The main issue with it is it is not taxed for road use and is therfore illegal to use in an on-highway vehicle. It is dyed red to identify it and will stain the tanks and fuel systems that it is used in. The only "lower grade" issue I am aware of would be the fact that the requirements for ULSD in off-higway diesel are a few years behind on-highway requirements so it is more likely that an off-highway diesel would be only LSD rather than ULSD.

Given the above issues do you really believe the station operators are going to risk selling an illegal fuel and the trucking companies/owner operators are going to risk damaging their $100K trucks with $30K engines by running the wrong fuel? I don't.

Originally Posted by jpeytonii

I would check your source regarding the "lower grade diesel" being sold at highway truck stops. First of all agricultural, or more accurately "non-road use" diesel, is not necessarily lower grade (though it could be). The main issue with it is it is not taxed for road use and is therfore illegal to use in an on-highway vehicle. It is dyed red to identify it and will stain the tanks and fuel systems that it is used in. The only "lower grade" issue I am aware of would be the fact that the requirements for ULSD in off-higway diesel are a few years behind on-highway requirements so it is more likely that an off-highway diesel would be only LSD rather than ULSD.

Given the above issues do you really believe the station operators are going to risk selling an illegal fuel and the trucking companies/owner operators are going to risk damaging their $100K trucks with $30K engines by running the wrong fuel? I don't.

Agree 100%.

Nobody will be selling Ag fuel from a pump to the public- too easy to get caught. First trucker to see red fuel would say "not in my truck" as he is making the phone call....

A

I agree, but truck stops sell the cheapest fuel they can get. Truckers don't want to pay any extra for premium diesel fuel. BMW does say to use 51 cetane, but lower centane will work, you won't get the performance of premium diesel fuel with a higher cetane.

Craig

Originally Posted by Craig B

I agree, but truck stops sell the cheapest fuel they can get. Truckers don't want to pay any extra for premium diesel fuel. BMW does say to use 51 cetane, but lower centane will work, you won't get the performance of premium diesel fuel with a higher cetane.

Craig

They do not "say" this in any document that makes it an "official recommendation".

At best there is a few comments published here and there, and a concerted effort by gas companies to create confusion around the concept of "premium diesel" so they can sell regular diesel, with their additives in it, for a handsome profit to worried car-diesel owners.

Originally Posted by ard

They do not "say" this in any document that makes it an "official recommendation".

At best there is a few comments published here and there, and a concerted effort by gas companies to create confusion around the concept of "premium diesel" so they can sell regular diesel, with their additives in it, for a handsome profit to worried car-diesel owners.

Well, this may not be an "official recommendation," but it was issued by BMWNA and list a contact at BMWNA:

http://www.bmwusanews.com/pdf.do?id=4

Originally Posted by Penguin

Well, this may not be an "official recommendation," but it was issued by BMWNA and list a contact at BMWNA:

http://www.bmwusanews.com/pdf.do?id=4

Yup, I've been in contact with their 'contact' over some other issues....

But first, please parse that document. The ONLY thing it says, relating to cetane, is:

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.

So this is NOT even a recommendation from BMW that you use 51 cetane. Period.

(Even more troubling, the wienies at BMW do not give a minimum cetane rating as I recall.)


Back to my contact with BMW. The only legally binding "instructions" for the vehicle are those that are (a) affixed to the car, (b) in the Owners manual, (c) in the other documents provided at purchase. No other press release, website posting, or dealer instruction can modify those items (without a recall!)

A

A group of stations where I live sells premium diesel for the same as regular diesel fuel. Cetane rating 49-51...

Craig

Originally Posted by ard

The only legally binding "instructions" for the vehicle are those that are (a) affixed to the car, (b) in the Owners manual, (c) in the other documents provided at purchase. No other press release, website posting, or dealer instruction can modify those items (without a recall!)

A

I am not suggesting that 51 is required, or that BMW will give anyone problems for using 40 cetane.

I am suggesting that the engine will likely perform better with diesel fuel that has a cetane higher than the US minimum of 40, and that is a legitimate reason to consider seeking-out higher cetane diesel fuel.

Folks in California- the minimum cetane for ANY diesel sold in an automotive pump (ie not a large truck nozzle) will be 48. THis is set by Calif Air Resources Board regulation.

So no need to buy any premium diesel.

Originally Posted by Penguin

I am not suggesting that 51 is required, or that BMW will give anyone problems for using 40 cetane.

I am suggesting that the engine will likely perform better with diesel fuel that has a cetane higher than the US minimum of 40, and that is a legitimate reason to consider seeking-out higher cetane diesel fuel.

I know- there are a few conversations going on. Someone did intimate that BMW said higher cetane is a 'recommended'.


I run 100 octane in the 996TT, which is modded and has programming to use the octane. Is it worth $7 a gallon? Yup. But that is 50hp or more difference! It would be interesting to see how much 'performance' BMW really is talking about.... anyone wanna run some Dynos?

A

Originally Posted by ard

Folks in California- the minimum cetane for ANY diesel sold in an automotive pump (ie not a large truck nozzle) will be 48. THis is set by Calif Air Resources Board regulation.

So no need to buy any premium diesel.

Here is Missouri, the average is 47 cetane for regular diesel...

Craig

Not to be argumentative, but "average" is different than "minimum allowable by law".