Cetane rating specific gravity. 44

[rbdjr]

Has anyone measured the cetane number on the fuel they been getting, GM recamends cetane number of 44, I cant seem to find anything over 40, then I played with the sample fuels I have and added Archoil, Amsoil, Hotshot, and added 1oz of the Archoil, 1oz of the hot shot 3 oz of the amsoil to 2 quarts of diesel fuel to see if any of them raised the cetane number with my OTC diesel fuel Hydormomiter. Did any of the factors affect the measured specific gravity number to increase the cetane number? Is this normal, as they all say they raise the number 4/8 numbers, no change on all? I'm not a chemist but was hoping to see maybe 1 cetane point higher, not sure how additives raise cetane ratings, note I have NO Top Tier diesel stations within 3oo miles of where I live in NJ. 20 years ago when working at a gm dealer we would not diagnose any diesel if we did not have a rating of 43 or higher? Has fuel quality dropped? Been teaching auto at a VoTech High School, and we are testing different samples of fuel seems 40 is the highest? It is mid-April here in NJ. I'm thinking the winterized fuel is gone, as all 4 samples I have taken from busy stations.
Anyone else check the cetane rating lately?

 

[HacksawMark]

I don't have a diesel fuel Hydormomiter so I haven't checked mine. I use Opti-Lube XL and XPD to raise cetane and lubricity when on road trips. At home (western Oregon) I always fill up with renewable diesel which is supposed to have higher cetane than diesel #2. I've been using XL for lubricity. Seems to run smoother than just diesel #2. So the question is: are these additives just placebos or do they work?

 

[rbdjr]

I don't have a diesel fuel Hydormomiter so I haven't checked mine. I use Opti-Lube XL and XPD to raise cetane and lubricity when on road trips. At home (western Oregon) I always fill up with renewable diesel which is supposed to have higher cetane than diesel #2. I've been using XL for lubricity. Seems to run smoother than just diesel #2. So the question is: are these additives just placebos or do they work?

15 years ago, 43 was the standard for # 2 passenger vehicle diesel, now I cant find anything over 40? weird

 

[DubVBenz]

There's one station in my town that sells 47, and you see all sorts of diesel enthusiasts filling up there. When I lived in the DC area, BP's that had Amoco Gold fuel had 50 cetane. I pay extra for the 47 in my Mercedes and LZ0

 

[HacksawMark]

I try to find renewable diesel when I can. It's cetane numbers are supposed to be in the 75 -90 range. I can find it at the local Circle K and 76 stations. It's the same or lower price than diesel #2

 

[rbdjr]

I just spoke with a GM Diesel Tech I worked with. He said GM now says a 36-39 Cetane rating is okay.
I now teach at an Automotive Technical High School, and our Book states 45 Cetane. Now our book is copyrighted from 2023, it could be outdated. The reason would maybe be the higher fuel pressures used today, as high as 35K PSI, the previous pressure used to be around 600PSI. Maybe the acceptable lower Cetane Rating is directly related to the Higher fuel PSI(35K).
I'm still on the search for a Higher Rating of diesel fuel rating, anything above 39?

 

[DubVBenz]

I try to find renewable diesel when I can. It's cetane numbers are supposed to be in the 75 -90 range. I can find it at the local Circle K and 76 stations. It's the same or lower price than diesel #2

You mean biodiesel? Not sure I'd want to run that in a modern diesel. Maybe if it's being sold by a gas station it's extremely well filtered and regulated? What's the cost? I've never heard of it coming from a gas station vs refining it yourself.

 

[DubVBenz]

I just spoke with a GM Diesel Tech I worked with. He said GM now says a 36-39 Cetane rating is okay.
I now teach at an Automotive Technical High School, and our Book states 45 Cetane. Now our book is copyrighted from 2023, it could be outdated. The reason would maybe be the higher fuel pressures used today, as high as 35K PSI, the previous pressure used to be around 600PSI. Maybe the acceptable lower Cetane Rating is directly related to the Higher fuel PSI(35K).
I'm still on the search for a Higher Rating of diesel fuel rating, anything above 39?

40 is the bare minimum in the mid-atlantic area, I've never seen anything below that and I've been driving diesels for 25 years.

 

[HacksawMark]

You mean biodiesel? Not sure I'd want to run that in a modern diesel. Maybe if it's being sold by a gas station it's extremely well filtered and regulated? What's the cost? I've never heard of it coming from a gas station vs refining it yourself.

No, renewable diesel is not the same as biodiesel. Renewable diesel and biodiesel have different chemical compositions. Renewable diesel is a much cleaner fuel to use than biodiesel.

Unlike pure diesel, biodiesel is a mix of diesel and biofuel. The most common biodiesel is B20, which contains between 6% and 20% biodiesel mixed with regular petroleum diesel. Another standard blend is B5, which has 5% biodiesel and 95% regular diesel. I've seen it advertised in the past as B20 on some Chevron stations along the Oregon coast although I wouldn't be surprised to see that they now have switched to renewable diesel.

Renewable diesel is produced from organic sources like cooking oils, waste animal fats, and even microalgae via hydroprocessing. The process used to make renewable diesel is similar to regular diesel, which makes it chemically identical to petroleum diesel. Some refineries will use soybean, canola, and carinate oils in making renewable diesel.

Biodiesel is made from vegetable oils, yellow grease, used cooking oils, and animal fats. It’s produced through transesterification, which turns fats and oils into two products: biodiesel and glycerin. I have actually met people who were making their own biodiesel in their garage, but that was 15-20 years ago. They would go to local restaurants and pick up their used cooking oil to use in the process. One guy had some very large vats in their garage. I never thought to ask what he did with it all afterwards.

Renewable diesel performs better in freezing temperatures without gelling issues due to its chemical similarity to petroleum diesel. Whereas biodiesel has a higher cloud point and can solidify at higher temperatures than renewable diesel.

I would never put biodiesel in my truck.