Cetane rating specific gravity. 44

rbdjr

rbdjr

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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?
 
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?
 
HacksawMark said:
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?
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15 years ago, 43 was the standard for # 2 passenger vehicle diesel, now I cant find anything over 40? weird
 
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
 
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
 
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?
 
HacksawMark said:
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
Click to expand...

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.
 
rbdjr said:
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?
Click to expand...
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.
 
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