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I got all this good information about Diesel fuel Cetane numbers.
But, the fuel stations in my area, west KY, have no idea what the diesel fuel cetane number is of the fuel they are selling.

So having the knowledge of diesel fuel ratings is worth squat.

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Do any of you guys know the fuel requirement of the Dodge 5.9 engine

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Cummins Fuel Recommendation:
A Cetane rating of at least 40 is recommended at temperatures above 32 degrees.
A Cetane rating of at least 45 is recommended at temperatures below 32 degrees.

gmcsmoke wrote:

remember the days when we just filled the tank up and drove.


Man I miss those days.

maxwell11 wrote:

I got all this good information about Diesel fuel Cetane numbers.
But, the fuel stations in my area, west KY, have no idea what the diesel fuel cetane number is of the fuel they are selling.

So having the knowledge of diesel fuel ratings is worth squat.

However, i did find out that some big diesel fuel stations offer two different cetane fuel ratings. But then you have to know the the diesel fuel cetane rating requirement of your vehicle before that informantion is of any value to you. My vehicle is a 2005 Dodge diesel pickup 5.9 engine and I have no idea its fuel cetane requirement.

Do any of you guys know the fuel requirement of the Dodge 5.9 engine?

So I kinda wasted my time requesting the informantion.

so far have not found the fuel cetane rating of the diesel at my local BP station and have made a second request for the information, guess they think I will just go away and quit bothering them, wrong. ____________________________________________

a cetane number which is too high may cause too short an ignition delay period. This changes the timing of the pressure peak, resulting in loss of power. When this happens, many of the performance problems associated with low cetane fuel will result. While the problems due to low cetane largely disappear after the engine warms up, with too high a cetane, these problems will persist even with a hot engine.

Cetane number is a measure of the ignition quality of a diesel fuel. It is often mistaken as a measure of fuel quality. Cetane number is actually a measure of a fuel's ignition delay. This is the time period between the start of injection and start of combustion (ignition) of the fuel. In a particular diesel engine, higher cetane fuels will have shorter ignition delay periods than lower cetane fuels.

There is no benefit to using a higher cetane number fuel than is specified by the engine's manufacturer. The ASTN Standard Specification for Diesel Fuel Oils (D-975) states. "The cetane number requirements depend on engine design, size, nature of speed and load variations, and on starting and atmospheric conditions. Increase in cetane number over values actually required does not materially improve engine performance. Accordingly, the cedtane number specified should be as low as possible to insure maximum fuel availability." This quote underscores the imnportance of matching engine cetane requirements with fuel cetane number.

Diesel fuels with cetane number lower than minimum engine requirements can cause rough engine operation. They are more difficult to start, expecially in cold weather or at high altitudes. They accelerate lube oil sludge formation. Many low cetane fuels increase engine deposits resulting in more smoke, increased exhaust emissions and greater engine wear.

Most cetane improvers contain alkyl nitrates which break down readily to provide additional oxygen for better combustion. They also break down and oxidize fuel in storage. This generates organic particulates, water, and sludge - all of which degrade fuel quality. The result is often a fuel which no longer meets even minimum requirements.



"University of Idaho scientists have conducted tests to determine the timeline and percentage of degradation of stored diesel fuel #2. The results of this testing was that the petroleum diesel fuel #2 degraded 26% after 28 days of storage."

so getting fuel from a high volume station is a good idea.

This statement by BP is false as octane and cretane are not the same thing. and your engine will not benefit from having more Cretan than the mfg requires the engine to have.
"BP Ultimate Diesel is suitable for use in all diesel vehicles and in independent tests* demonstrated benefits over ordinary diesel with ongoing use. Importantly, the new fuel is guaranteed to deliver above the minimum Australian standard cetane rating. Cetane is to diesel what octane is to unleaded fuel. The minimum Australian cetane rating standard is 46. BP Ultimate Diesel has a guaranteed minimum cetane rating of 50."http://www.bp.com/genericarticle.do?categoryId=9008681&contentId=703 7038

Definition: The Cetane Number (abbreviated CN) refers to the combustion quality of diesel fuel. It represents the time delay between the start of injection process and the the point where the fuel ignites.

This value is determined by the % volume of cetane or
hexadecane (C16H34) in isocetane that provides the identical ignition delay of the measured fuel sample.

While gasoline's octane signifies its ability to resist auto-ignition (also referred to as pre-ignition, knocking, pinging, or detonation),

Using diesel fuel with a higher cetane rating than is required for a particular diesel engine design yields no bonuses. Cetane number requirements depend mainly on engine design, size, speed of operation and load variations--and to a slightly lesser extent, atmospheric conditions. Conversely, running a diesel engine on fuel with a lower than recommended cetane number can result in rough operation (noise and vibration), low power output, excessive deposits and wear, and hard starting.

Normal modern highway diesels run best with a fuel rated between 40 and 55. Following is a list cetane numbers varying grades and types of compression ignition diesel fuels:
Regular diesel--48
Premium diesel--55
Biodiesel (B100)--55
Biodiesel blend (B20)--50
Synthetic diesel--55