BP Diesel Fuel

VACRD · **Posted:** Sun Apr 05, 2009 10:50 am

I have read in the past that BP diesel fuel had a higher ocatane rating.

I have found a couple of stations that sell it for around $2.19 per gallon and started using it for my CRD.

Last fill up for my CRD I got 27 mpg at 50% hw and 50% city. 27 mpg is the highest I have ever got in mixed driving over 53,000 miles.

Was wondering if anyone else had similar results with BP diesel fuel?

I also have a 2009 Jetta TDI with 3,000 miles - have averaged 44 mpg on 100% highway driving. Can not wait till it gets broken in.

BVCRD · **Posted:** Sun Apr 05, 2009 12:06 pm

They probably just switched back over to summer fuel. That'll help mpg's. Their site says they sell 47 cetane. No biggy.

http://www.agland.coop/images/E0173401/bpulsds_pi.pdf

MOSFET · **Joined:** Sat Feb 25, 2006 11:40 pm **Posts:** 295

When I was down there I would always get B20 at the Quarters K station near the Pentagon.

https://www.nexnet.nexweb.org/pls/nexjobs/nx_display_facility?p_facility_no=089

The big mpg change is probably due to the winter/summer switch.

DarbyWalters · **Posted:** Sun Apr 05, 2009 2:00 pm

Not higher Octane Rating which is for gasoline...higher octane makes it more resistant to detonation.

You mean higher Cetane which is for Diesel...higher Cetane makes it less resistant to detonation...so it burns easier...better for Diesel.

Joe Romas · **Posted:** Sun Apr 05, 2009 5:44 pm

Actually 47 cetane is a biggie when most claim 40 :shock:

But 50 as in Europe would be better :lol:

BP in Ohio used to be Sohio that had Diesel Supreme that was a etter fuel but in central Ohio it has not been available for years even though some dealers still have diesel supreme signs :roll:

BP is now calling their gasoline Ammoco because their products had such a good bad reputation :cry:

You won't see the best mileage on you jetta till it's broken in at around 20,000 miles :lol:

My 99.5 jetta averaged 49.6 mpg mostlly highway for 114k miles :lol:

BVCRD · **Posted:** Sun Apr 05, 2009 6:38 pm

Most in America claim in the 40's. It's not like it gives us any more power.

UFO · **Posted:** Mon Apr 06, 2009 1:42 am

BVCRD wrote:

Most in America claim in the 40's. It's not like it gives us any more power.

That's correct. My biodiesel is 50 cetane, and the mileage drops a little.

nursecosmo · **Posted:** Mon Apr 06, 2009 2:51 am

UFO wrote:

BVCRD wrote:

Most in America claim in the 40's. It's not like it gives us any more power.

That's correct. My biodiesel is 50 cetane, and the mileage drops a little.

Well of course it gives more power. That is why the MPG goes up with premium fuel. It gives a longer smother burn which improves the torque. However the bump in MPG does not usually offset the difference in price.

FYI UFO, BD has aproximatly 130000 BTU per gallon whereas D2 has aproximatly 140000. But the Drop in MPG if any, (some engines get better MPG with BD) does not correspond to the BTU value because of it's increased Cetane.

BVCRD · **Posted:** Mon Apr 06, 2009 8:25 am

The way I read it, it gives better ignition of fuel, and smoother running, but no more power. It also contains additives that MAY clean things and add
lubrication. Might be best to just mix your own though.

ARE BOTTLED ADDITIVES A GOOD DEAL?

Generally yes. Premium diesel is 5¢ to 15¢ per gallon higher than standard. You are assured of good quality in one to five important properties of diesel fuel. Additives cost 2¢ to 4¢ per gallon to assure good quality in one important property of diesel fuel: to remove water, to clean injectors, to lower pour point, to boost cetane three numbers, or to add lubricity. Combination additives assure good quality in several important properties of diesel fuel, and cost 5¢ to 10¢ per gallon. In most cases - but not all -- you’ll get more benefit for less money by using bottled additives.

UFO · **Posted:** Mon Apr 06, 2009 11:29 am

nursecosmo wrote:

UFO wrote:

BVCRD wrote:

Most in America claim in the 40's. It's not like it gives us any more power.

That's correct. My biodiesel is 50 cetane, and the mileage drops a little.

Well of course it gives more power. That is why the MPG goes up with premium fuel. It gives a longer smother burn which improves the torque. However the bump in MPG does not usually offset the difference in price.

FYI UFO, BD has aproximatly 130000 BTU per gallon whereas D2 has aproximatly 140000. But the Drop in MPG if any, (some engines get better MPG with BD) does not correspond to the BTU value because of it's increased Cetane.

I'd like to see that documented. Cetane is not an indication of how much energy is in the fuel. I was using biodiesel as an example.

nursecosmo · **Posted:** Wed Apr 08, 2009 10:05 pm

UFO wrote:

I'd like to see that documented. Cetane is not an indication of how much energy is in the fuel. I was using biodiesel as an example.

It's very difficult to find any research available for public viewing without paying for it. When I was in college I could get copies of any study ever performed on anything in the universe. Boy do I miss that. Anyway I have found some indirect evidence of power increase with high cetane fuels. By high cetane I refer to cetane numbers of 50-60. Here is a nice study by the Oak Ridge National Laboratory. Page 15 shows a significant increase in low temp heat release and corresponding decrease in peak temp and pressure spike. Temperature and pressure spikes in a combustion engine are wasted energy as much of the spike becomes lost to the coolant and pressure to engine flexing. http://www1.eere.energy.gov/vehiclesand ... unting.pdf

A premium high cetane fuel usually has a higher energy content than the cheap ULSD now sold. The desulfurization process removes more of the aromatics, which decreases the density of the fuel and leaves a higher percentage of alkanes in it. Most ULSD D2 ranges fromC10H20 to C15H28, with C12h23 being the average. Hexadecane (cetane) has a chemical number of C16H34, having a higher heat value per molecule. In fuel with higher natural cetane, the usable BTU value is higher.

In larger slower rpm engines, cetane has little effect on power output because the the fuel is completely combusted by the time the piston is through the power stroke. However, in small high speed engines like ours, without dynamic timing adaptability, the shorter ignition time delay caused by increased cetane value, causes the main burn event to initiate at the beginning of the power stroke vs the middle of it. This translates to higher torque and hp and is the reason why diesel dragsters need high cetane premium fuel.

In the most modern varieties of diesel engines such as the VM Motori Panther, the CPU senses when ignition occurs through the glow plug and can dynamically advance or retard the timing in accord with the ignition characteristics of each tank of fuel. This kind of engine benefits very little from a higher cetane number fuel.

here is some further reading.
http://books.google.com/books?id=yzhgRq ... 3#PPA99,M1

http://books.google.com/books?id=FHtgXj ... t&resnum=7

UFO · **Posted:** Thu Apr 09, 2009 11:39 am

I can accept that a higher cetane diesel fuel may impart more power or better efficiency than a lower cetane petroleum diesel fuel. Perhaps if you can compare two fuels with identical energy content, differing only in cetane, you might find the higher cetane gives the advantage. My only point remains that cetane number alone is not responsible for whether the fuel in question will give more power or better mileage. It's not, as I said, biodiesel can be added for higher cetane, and still impart less mileage/fuel efficiency. It would seem to be a moot point anyway, as no fuel distributor reveals the cetane rating on pumps anymore, so who knows what you are getting.

warp2diesel · **Posted:** Thu Apr 09, 2009 1:25 pm

Of course the closer we can get to 50 Cetane the better.
By doing ORM or SEGR we supply more oxygen to the burning process and in a back handed way come closer to the burning characteristics of 50 Cetane fuel with the junk we have in the US.
Older diesels would have to have the timing very slightly retarded to compensate for this. Since the Off Road and Heavy Duty Over The Road Diesel Owners have a strong lobby to keep it the way it is so they don't have to readjust the timing, we loose. If we had more light duty diesels like Europe and an automotive industry that had some guts, we would have 50 Cetane fuel in the pumps. Add the Wack Job Junk Pseudo Scientists grasping onto their Fairy Tail Nitrous Oxide into the mix, we have the mess we are in.

In a lot of gassers with marginal to poor designed combustion chambers that have hot spots and sharp edges (not all engines are Hemis), the EGR acts like a Pseudo Octane Booster. Disconnect an EGR on a gasser and you may put holes in the pistons, disconnect the EGR on a Diesel, it will run much better.

nursecosmo · **Posted:** Thu Apr 09, 2009 3:04 pm

warp2diesel wrote:

Older diesels would have to have the timing very slightly retarded to compensate for this.

You ADVANCE the timing for a low cetane value, but I hear what you're saying.

warp2diesel · **Posted:** Thu Apr 09, 2009 7:11 pm

nursecosmo wrote:

warp2diesel wrote:

Older diesels would have to have the timing very slightly retarded to compensate for this.

You ADVANCE the timing for a low cetane value, but I hear what you're saying.

To run on 50 Cetane OLDER diesel engines need to have the timing retarded. I was discussing 50 Cetane in the previous sentence. Why would you think I was referring to any thing else other than 50 Cetane?

nursecosmo · **Posted:** Fri Apr 10, 2009 1:33 pm

warp2diesel wrote:

nursecosmo wrote:

warp2diesel wrote:

Older diesels would have to have the timing very slightly retarded to compensate for this.

You ADVANCE the timing for a low cetane value, but I hear what you're saying.

To run on 50 Cetane OLDER diesel engines need to have the timing retarded. I was discussing 50 Cetane in the previous sentence. Why would you think I was referring to any thing else other than 50 Cetane?

My bad. I guess I should have got that.

BP Diesel Fuel

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