View Single Post
Old 07-03-2003, 12:50 AM
BoostnBenz's Avatar
BoostnBenz BoostnBenz is offline
Benötigt Mehr Druck!
Join Date: Aug 2002
Posts: 1,855
Best diesel fuel stations? Cetane levels. Premium diesel. (long)

Hi all,
I've been wondering these kind of things for a while now, it seems as if no fuel stations post their cetane level of the diesel fuel. Every station I've went to before and asked the attendant they looked at me all confused and reply that they don't know. So what did I do? I emailed the corporate websites of my two most common stations. I also read up on some older threads to find a few opinions that;
Sunoco doesn't yield as good as fuel mileage, not very good fuel.
Cenex is yields better than average fuel mileage.
Amoco makes a premium diesel with much higher than normal cetane levels, however it comes at a cost and is sort of hard to find.

After emailing Marathon Ashland Petroleum (CMS, Marathon, Speedway) they replied that:

Marathon Brand doesn't actually sell a premium diesel in Michigan. Sometimes the supplying jobber will do their own thing and sell it by blending an additive with our fuel. We don't have any specific information on premium diesel. There is an industry standard from the National Conference of Weights & Measures definition of Premium Diesel. Here it is:

[quoted from email, from NCWM's website]
NCWM's Premium Diesel Fuel Standards & Tests
The following are the five performance properties that comprise the National Conference on Weights and Measures (NCWM) Premium Diesel Fuel Standards. A Fuel marketer must meet at least two standards in order to be able to advertise "Premium Diesel" in states that adopt the NCWM standards.
Energy (Btu) Content: The fuel must have at least 138,700 Btu, as measured by ASTM D-240
Cetane Number: The fuel must have a cetane number of at least 47, as measured by ASTM D-613.
Fuel Injector Cleanliness: The fuel must either pass a CRC rating test with a 10.0 or less, or it must have a flow loss of 6.0% or less on the Cummins L-10 test.
Low Temperature Operability: The fuel must provide cold-flow performance down to ASTM D-975 tenth percentile minimum ambient air temperature charts and maps for the region and time of year where the fuel will be sold. This performance must be proven through use of the Low-Temperature Flow Test, also known as ASTM D-4539, on the Cloud Point Test.
Thermal Stability: The fuel must get at least an 80% reflectance measurement using a filter in the Octel F21-61 test.
After researching further at that site I found that in order to be claimed diesel it must meet two of those criteria. BP/Amoco hasn't yet replied, maybe I'll give them a call if they don't soon or I don't gain enough info here. Do you notice better mileage with any certain stations? Do you notice worse with some?

My own observations:
Sunoco is decent fuel, yields decent mileage
CMS is good fuel, yields decent mileage
SpeedyQ is poor fuel, yields OK mileage
BP is good fuel, yielded me my record mileage of low 30s on winter blend.

My biased opinion, I like BP because they have pay at the pump in my area and they pumps pump very very quick. Neither CMS or Sunoco use pay at the pump and both pump mediocre. SpeedyQ pumps the slowest, but uses pay at the pump. While biased opinions are fine, I wouldn't mind seeing some stats or facts, especially if you get better fuel mileage on one brand vs another.
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k
Reply With Quote