I was wondering if anyway has found an improvement with the running of their car on Premium Diesel Fuel as opposed to the standard Diesel Fuel. In Melbourne Australia we are just getting the premium fuel appearing in our petrol stations. Just put premium in mine for the first time recently. So far seems smoother and less black stuff out the back!

Marketing scam. Only difference is more additive to increase cetane.

It's only a scam if the cetane isn't increased. More cetane is useful and should bring a bit higher price, although hard to know when the price increase is logically proportional.

This doesn't sound like snake oil :-

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

I will be trying it out .

I like Shell "Super" diesel and Sunoco "Gold" diesel. The premium grades sell for the same price as Premium gasoline (91 octane) in Toronto.

Personally I feel the engine runs smoother with premium.

Your spanking new C350 CDi should have zero black smoke with any auto diesel fuel, premium or not. Take the car back to the dealer if it blows soot.

Your car must be a flyer. 400 foot pound of torque in a C body. We do not get that in North America.

Perhaps diesel particulate filter not required in Australia?

My 2008 Australian W 204 220 CDI does not have a particulate filter.I am pleased as there is one less item to go wrong. I have soot deposits on the rear bumper & a grey haze from the exhaust when accelerating hard.

My previous car , a diesel Peugeot used to blacken out the oncoming traffic if the turbo charger was caught out with heavy acceleration

I have been told that particulate filters have two sensor pressure lines measuring differential pressure across the filter for regeneration.

Check your exhaust to see.

Thanks Guys, yes loving the 350CDi.

I have had the same thing happen to mine as "Carsy." Soot coming out the back up the bumper and boot, and even discolouring the inside of number plate covers. I have definitely noticed less soot coming out the back since using the the Premium Diesel. The car does not put clouds out the back under hard acceleration as much either. I have been using the premium diesel for about 4 weeks now. So for me, whilst it might cost a little more, I am continuing to use it. I have bought it from Caltex stations...

Are your exhaust tips bent or straight like a gaser? The older MB diesels have bent tips so the soot will hit the ground after exiting the system. You are lucky to have diesel MBs without the filter. What is the power output? I am sure both output and fuel economy are marginally better.

Do you have low sulfur diesel (LSD) or ultra low sulfur diesel (ULSD) in Australia? More of the yellow stuff, more power and lubrication. There is a penalty to be paid for "clean" diesel engines.

My chipped 1999 VW Jetta TDi blew black smoke too under hard acceleration too! I like it.

No, the exhaust tips are straight but a good point to think about. The tips seem adjustable so can he moved out but then there is a danger with rear parking mishaps.

The C 220CDI is 125 KW @ 3800 rpm & 400NM of torque @2000 rpm.

Australia's new regulations allows 10 parts per Million Sulphur in the diesel fuel.

Wrong. Sulfur is a contaminant that has zero benefit to being in the fuel.

Correct.

Higher Cetane Diesel Fuel is going to yield more complete and smoother combustion pressures resulting in a quieter,smoother engine and improved MPG -VS- low Cetane US garbage fuel.

100% True !!

Well, not exactly. There are two sides to sulfur.
Sulfur can increase acidity, but other additives should control the acidity - to ATSM standards.
Sulfur is a lubricant, and that property is largely lost with ULSD. Again, the ATSM standards now specify a minimum level of lubricity, so fuel suppliers must have an additive package to bring that lost lubricity back up.
As of 12/1/2010 all retail outlets in the US can't sell anything BUT ULSD. So whether your like or dislike the new emission controls, whether you are hooked on 2006 technology or prefer the new technology, it's what we have.

BP in virginia carries 47 Cetane. I have yet to find higher, and have even poked around the tdiclub forums to see if anyone else knew of stations in my area that are higher. On a positive note, I filled up today and 47 Cetane in Charlottesville, VA was cheaper than premium!

That is false information.

Also false information. The process of removing the sulfur is what lowers lubricity, sulfur itself has no beneficial qualities.

ALL retailers have been selling ULSD since 2006. 12/1/10 was the deadline for getting their equipment certified to dispense it without risk of contamination from residual LSD fuel deposits.

That cannot be determined or verified as an accurate statement. There is no standard for cetane level and it varies greatly from shipment to shipment. Also, station clerks have little to no knowledge of the fuels they dispense, he was likely just blowing smoke up your butt to make you stop asking questions.

Well, not exactly. The molecular associations formed with sulfur increase lubricity. So, sulfur does increase lubricity, if only indirectly.
You are partly correct in saying the process of refining out the sulfur reduces lubricity, but it's the loss of the associated aromatics, with their energy content, that is the real culprit here.
Whatever the case, removing sulfur reduces lubricity (and bacteria growth inhibitors), which must be restored by the producer.
Costs increase both by the removal of sulfur and by the measures needed to restore the lost lubricity and reintroduce bacterial growth inhibitors.
The earlier solution to addressing sulfur in fuel consisted largely of neutralizing acid and acidic products of combustion - a much cheaper approach than is now required by removal, especially when the ramifications are considered.
It's a matter of semantics as to whether sulfur was advantageous. But removing it has its disadvantages, too.

That is false information.

Also false. If sulfur has beneficial properties, why does sweet crude (oil with low sulfur) command nearly 3 times the price of sour crude?

Incorrect. Sulfur was necessary to remove for efficient catalytic devices to be implemented. The cost of sulfur-resistant catalytic devices that are able to meet current emissions limits would be far greater than the cost of removing sulfur from the equation, both from a materials cost and emissions (mining the precious metals).

Incorrect. Contamination, by definition, has no advantage.

Also incorrect. The only disadvantage was the cost of retrofitting refineries.

OK, 240 - Here's your chance to show everybody how much you really know!
Line by line, Name Your Peer-reviewed Sources!

He's correct on all points.

You present your "data" first.

Ok, let's address some of 240's misinformation one at a time. This will take a while, but here's a start:

Truth: Sept 27, 2010 article http://www.petrolplaza.com/news/indu...c0NCYmMQ%3D%3D

USA changes diesel fuel standards in December

Source: Datamonitor | Posted / Last update: 27-09-2010
Gasoline stations are upgrading their diesel fuel to comply with the new EPA standards
In three months, all U.S. gasoline stations must sell Ultra Low Sulfur Diesel (ULSD) fuel, which has a maximum of 15 parts per million of sulfur. This fuel will replace Lower Sulfur Diesel (LSD), which has up to 500 parts per million of sulfur.

The change to ULSD begins December 1 due to new regulations by the U.S. Environmental Protection Agency taking effect. The agency lowered sulfur levels in diesel to improve air quality. Diesel engines in 2007 model year or higher need ULSD fuel to drive correctly.

Currently, only 80 percent of highway diesel fuel made in the United States has ULSD, but the regulations will change that to 100 percent. Many gasoline retailers have started making the change. For example, the New Jersey Gasoline-C-Store-Automotive Association has found that around 800 of the 2,800 N.J. gasoline retailers already offer ULSD fuel.

“Diesel engines get better gas mileage than normal gasoline engines, the turn off is that they also produce more pollutants,” said Nick De Palma, the association’s spokesman. “But because they’re dropping the sulfur level to 15 parts per million, this diesel fuel is good for the environment and will earn better miles per gallon.”

Civil penalties of up to $32,500 daily for stations not complying with ULSD fuel standards could be assessed by the EPA. In June, the agency clarified labeling requirements for diesel fuel.

Three times? All other things being equal, sour sells for roughly 80-90% of sweet crude. Here is a chart that not only shows relative prices, but page 2 discusses various factors that enter into the pricing of oil delivered to the "receiving agency."

http://www.paalp.com/_filelib/FileCa...ry_20_2011.pdf

API gravity (light / intermediate / heavy, where "light" is greater than 40.0) plays a major role in market price, as you can see from the chart.

I actually have references to support what I have written with one exception. Unfortunately they are in the form of papers from the Institution of Mechanical Engineers U.K, Chevron, Conoco, Cummins and the like. Hundreds of pages.
I really don't have the time to scan them and post them, but I will try to find links to the docs so you can visit them on the web.

In the meantime, my challenge to 240D is to share his wisdom with the rest of us.
A reference here and there that supports his "that's false information" mantra would benefit us all!

If his references are credible, then we can discuss the differences in informatoin.