Ask them to prove it at the station! This has been discussed many times on the TDI forums and folks have seen the same truck fill a "premium" tank and then go down the road and fill a 40 cetane diesel pump. There seems to be no law whatsoever covering what has to be in "Premium" diesel. My advice. Buy from a high turnover, reputable company. I use Esso (Exxon) diesel and always add Power Service Gray bottle in the summer and white bottle in the winter. Both increase your cetane ratin.
I don't see how diesel could have more then one blend, in regards to the cetane ratings. I think diesel is diesel anywhere you get it.
The main difference, in my opinion is the bio-blend diesel and however it effects the engine and supporting components.
I read that too much bio-diesel isn't a good thing, so I try to stick with reputable stations that don't display any bio stickers, just the typical 15ppm low sulfur stuff. If not available, I'll gladly pump 5% bio but anything beyond that just doesn't sit well with me, even though I'm forced to pump bio 20% a lot at truck stops around this great country of ours...
Shell's Pernis refinery makes some great diesel and they are very, very tight-lipped about how they do that.
There is such a thing as Premium Diesel in the USA.
There are such things as cetane improver additives but I've never seen then available at the retail level and I doubt they'll ever be available at the retail level due to what they're made of.
Tanker trucks can have more than one compartment, 4 is a very common number.
CARB diesel is its own different beast as well.
Cetane imprvers are all over the place at retail. Diesel Kleen gray bottle....gives a six point boost using ethylhexyl nitrate. You need to "bone up" on these if you have a diesel. They are advertised in all of the diesel magazines and can be found at WalMart, NAPA, AutoZone, etc, etc.
What are the benefits of such additives and is there proof that it actually works? I know your average fuel additive also promises a bunch of stuff but I've read they barely do anything and are mostly just gas.
I don't remember my owners manual saying anything about additives, so I've been running the Ram with just plain diesel. Is it really worth spending money on additives?
Cetane is simply an indicator of how fast the fuel will ignite in the cylinder. The higher the number, the quicker it will ignite under compression. Good for cold weather starting, good for emissions, not so good for fuel mileage. Theres a bit of a misconception that the higher the cetane number the better an engine will run....not totally true. Diesel engines are designed to run off of a set standard of fuel much like gasoline engines are designed to run off of a minimum octane. So long as you are running your engine with the proper fuel, there is no real benefit to adding any kind of cetane booster. in cold climates there is a winter grade fuel which will have an additive to boost the cetane content by a few points to aid in cold weather starting so generally speaking using additives with cetane boost are not necessary then either. The exception is a cold snap where it may drop well below "average" temps for the time of year, I may occasionally add some anti gel additive which coincidentally has a healthy shot of cetane boost as well...In all truthfulness it's likely not necessary but I live in a rural area and am on the road very early in the morning so I'd rather play it safe than end up on the side of the road with gelled fuel.
Personally, I'm more concerned with adding a good quality lubricant than anything, especially since I own older diesel engines with rotary style injection pumps.
I have seen some outlets that promote "premium diesel", but they did it via adding something like Schaeffer diesel fuel additive as part of the mix in the tanks. The other way, would be in the upper tier of the U.S., where #1 diesel is blended with #2 for cold weather flow properties. Other than this, i have seen no appreciable difference in diesel across the upper tier of the U.S. I go thru over 21,000 gallons of diesel, average, per year. I experience no difference between so called "premium diesel" outlets and the discount places. I guess because of that, the discounts I get by patronizing certain outlets, and the volume of fuel I use, cost to go with some sort of "premium diesel" is not worth it. The other day, I got diesel at $1.04 off the cash pump price of $3.86. I got the fuel for $2.72 a gallon. Nope, I am not going to pay an extra $1.04 a gallon for some "premium diesel' when I can put in the same additives they do for roughly $.03 cents a gallon.
There are certain conditions where additives are a good thing. A lot of folks focus on lubricity, but that is really a non issue with modern engines nowadays. It is the other stuff that can be of concern. Presence of water in diesel, microbes that want to set up house in your fuel tanks and cause problems, and is the case with common rail fuel systems on many new diesels, an excessive amount of heat the fuel is subject to that can lead to a condition called Asphaltine, where the fuel is "cooked" to the point where carbon chains are being produced that can cause issues. This hot fuel is returned off the rail to the fuel tanks and these asphaltine particulates can build up in fuel lines and filters. A good additive can help reduce this problem by breaking these down.
But, to each his own.
Bio is great for lubricity. Better than any additive on the market. And most diesel fuel stops for trucks already are blending bio in the diesel. So there is no cost to give it a try. I have been using various blend of bio in fuel for 6 years, 21,000 gallons of diesel per year average, and have never had any issues with it. It does have some cold flow limitations and can choke up a fuel filter quicker in cold weather, depending on micron rating of the fuel filter.
You do it right, and there is no more issues with bio blends than regular diesel. Running between 5 and 15 percent, I can go 20,000 miles on a fuel filter. Only change it then because of doing oil change also in my semi truck and fuel filter gets changed at each oil change.
In order to be classified as PREMIUM DIESEL, it must meet the following requirements (this is according to the National Conference on Weights and Measures):
Sulfur content less than 15ppm (The same as ASTM D975).
Cetane number 47 (vs 40 for ASTM D975).
Improvement in cold flow over un-additized fuel.(10th percentile minimum)
Thermal Stability rated at over 80% (vs no requirement in ASTM D975).
Lubricity no greater than 520 micron wear following HFRR test protocol (The same as ASTM D975).
The fuel may be additized at various places along the cycle coming from the refinery. Most often it is handled at the terminals or left to the individual marketer (fuel company distributors) to mix the additives on their own.
It was just announced that there will be a Top Tier diesel program. I stumbled across it recently on the Top Tier website when confirming that my regular fuel station is not Top Tier for my new gas vehicle.
"A TOP TIER™ Diesel Fuel program is being launched to benefit owners of diesel-powered vehicles and diesel-powered equipment. Today’s diesel engines typically utilize high pressure common rail (HPCR) technology where smaller tolerances and higher fuel pressures are seen. HPCR engines will benefit from the requirements stated in the TOP TIER™ Diesel Performance Standard, developed by a consortium of diesel Original Equipment Manufacturers (OEMs). Retailers offering diesel fuel and biodiesel blends meeting the TOP TIER™ Diesel Fuel requirements will display the TOP TIER™ Diesel Fuel logo at the dispensers or elsewhere in their stations starting October 2017." (http://www.toptiergas.com/top-tier-diesel-fuel/)