Montana Owners Club - Keystone Montana 5th Wheel Forum - View Single Post

richfaa · 11-01-2008, 02:49 PM

I have read that the new Diesel motors require a cetene rating of 45..Consider this..

"Diesel at the pump can be found in two CN ranges: 40-46 for regular diesel, and 45-50 for premium. The minimum CN at the pump is supposed to be 45. The legal minimum cetane rating for #1 and #2 diesel is 40. Most diesel fuel leaves the refinery with a CN of around 42. The CN rating depends on the crude oil the fuel was refined from. It varies so much from tanker to tanker that a consistent CN rating is almost impossible. Distilling diesel is a crude process compared with making gasoline. Gasoline is more of a manufactured product with tighter standards so the octane rating is very consistent. But, the CN rating at the diesel pump can be anywhere from 42-46. That’s why there is almost never a sticker on a diesel fuel pump for CN"

So what are we getting in the ULSD 40, 42,46????My thought is there is no way to know. I am sure that the motor will run Ok at a CN rating of 40-42 but I'll bet it will run beter at a CN of 45-50. We have always used a additive in the 08 6.4l on the advise of several Diesel tech's that I figure know more than I do. Here in Florida we use Shell Premimum Diesel and I am convinced that this 08 runs better with the additive or the Shell premimum and gets a bit better MPG. IMO that is...

11-01-2008, 02:49 PM	#11
richfaa Montana Master Join Date: Jan 2005 Location: North Ridgeville Posts: 20,229 M.O.C. #2839	I have read that the new Diesel motors require a cetene rating of 45..Consider this.. "Diesel at the pump can be found in two CN ranges: 40-46 for regular diesel, and 45-50 for premium. The minimum CN at the pump is supposed to be 45. The legal minimum cetane rating for #1 and #2 diesel is 40. Most diesel fuel leaves the refinery with a CN of around 42. The CN rating depends on the crude oil the fuel was refined from. It varies so much from tanker to tanker that a consistent CN rating is almost impossible. Distilling diesel is a crude process compared with making gasoline. Gasoline is more of a manufactured product with tighter standards so the octane rating is very consistent. But, the CN rating at the diesel pump can be anywhere from 42-46. That’s why there is almost never a sticker on a diesel fuel pump for CN" So what are we getting in the ULSD 40, 42,46????My thought is there is no way to know. I am sure that the motor will run Ok at a CN rating of 40-42 but I'll bet it will run beter at a CN of 45-50. We have always used a additive in the 08 6.4l on the advise of several Diesel tech's that I figure know more than I do. Here in Florida we use Shell Premimum Diesel and I am convinced that this 08 runs better with the additive or the Shell premimum and gets a bit better MPG. IMO that is...