Cetane rating
07-18-2005, 07:03 PM
#1
Registered User
Thread Starter
Cetane rating
I've had my 99 since new and apart from an evap core rot and some paint problems It's the best buy I've ever made.
My question, I see 40, 42 and 45 cetane fuel. I've run full tanks of each without seeing any real difference. I live in Virginia so cold isn't realy been an issue. what is the difference? TDR forums never gave me any info. It seems the truck stops that have the freshest fuel carry the 40 (much cheaper) and the neighborhood service(?) stations carry the 45 for the VW TDIs but who knows how long that stuff has been underground growing green stuff.
My question, I see 40, 42 and 45 cetane fuel. I've run full tanks of each without seeing any real difference. I live in Virginia so cold isn't realy been an issue. what is the difference? TDR forums never gave me any info. It seems the truck stops that have the freshest fuel carry the 40 (much cheaper) and the neighborhood service(?) stations carry the 45 for the VW TDIs but who knows how long that stuff has been underground growing green stuff.
07-18-2005, 07:37 PM
#2
Registered User
I can't really explain it, and the web page I bookmarked that did, is not gone, so here's other links that may help. I don't really worry about cetane in my trucks.
http://dodgeram.org/tech/dsl/FAQ/diesel_fuel.htm
http://www.mda.state.mo.us/FuelQuality/e1d.htm
http://www.prime-mover.org/engines/G...es/octane.html
Chris
http://dodgeram.org/tech/dsl/FAQ/diesel_fuel.htm
http://www.mda.state.mo.us/FuelQuality/e1d.htm
http://www.prime-mover.org/engines/G...es/octane.html
Chris
07-18-2005, 07:38 PM
#3
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cetane is diesel's octane equivelant, octane is an 8 base unit molecule, cetane is a 7 unit one, the rating refers to a percentage of purity, not sure if it is a 100 scale like percentages or 200 like proof. seeing racing gas over 100 octane make me think its not a straight 100 scale.
07-19-2005, 08:53 AM
#4
Registered User
My memory may be fading but I think I recall reading that the minimum standard is 40 and that there are no additional benefits above 50. The higher the number the higher the btu contentI may be wrong on the btu content) and higher performance. (performance not only includes engine performance but the performance of the fuel as well, such as starting in cold weather, mileage etc).
In addition unlike gasoline, diesel pumps are not required to post the cetane rating of diesel(unless mandated by the state specifically which the vast majority do not). If they do post, it must meet that rating. And premium diesel does not necessarily mean higher cetane. Premium diesel has what they refer to as the 2 of 5 rule. It can be called premium if it meets 2 of 5 criteria. Cetane is only one of those criteria. Cloud point, lubricity, cetane, detergancy and one other that I cant remember are the 5 criteria I think. So when you buy premium fuel you are not sure of what you are really getting(not that you are sure what you are getting when you buy non premium either) and it may change from one tanker load to the next and still be premium.
Warning Will Robinson Warning!(as my arms are flailing) Additive Sales pitch to follow
With that being said I do not spend the extra on premium fuel even when I can find it. However I do use an additive. There are many out there and my personal choice is called Amalgamated. I think the one I use is called the w-tdr blend but they have many. Unfortunately you cannot buy it over the counter. You have to buy direct from them in a 5 gal pail. (5gals will do 1880 gals of fuel, 50 for the pail and 40 for shipping even with shipping it works out to be about 4.7 cents per gal of treated fuel) Kind of a pain to deal with but worth it in my imo.
http://www.amalgamatedinc.com/news.htm
I would suggest you call and talk to them (Gary Pipenger) about additives and fuel qualities. They have many independant studies published about their additives and additive blends. As with any independant tests supplied by a vendor you sort of have to read through the propaganda and look at the test results for yourself but after you do I think you will find a wealth of info and that many of the over the counter ones do not do what they say or are misleading in their wording of what they say it will do. Sorry didnt mean to turn this into a sales pitch for my additive of choice I just found their test info very interesting.
I am in no way connected with Amalgamated other than a user.
In addition unlike gasoline, diesel pumps are not required to post the cetane rating of diesel(unless mandated by the state specifically which the vast majority do not). If they do post, it must meet that rating. And premium diesel does not necessarily mean higher cetane. Premium diesel has what they refer to as the 2 of 5 rule. It can be called premium if it meets 2 of 5 criteria. Cetane is only one of those criteria. Cloud point, lubricity, cetane, detergancy and one other that I cant remember are the 5 criteria I think. So when you buy premium fuel you are not sure of what you are really getting(not that you are sure what you are getting when you buy non premium either) and it may change from one tanker load to the next and still be premium.
Warning Will Robinson Warning!(as my arms are flailing) Additive Sales pitch to follow
With that being said I do not spend the extra on premium fuel even when I can find it. However I do use an additive. There are many out there and my personal choice is called Amalgamated. I think the one I use is called the w-tdr blend but they have many. Unfortunately you cannot buy it over the counter. You have to buy direct from them in a 5 gal pail. (5gals will do 1880 gals of fuel, 50 for the pail and 40 for shipping even with shipping it works out to be about 4.7 cents per gal of treated fuel) Kind of a pain to deal with but worth it in my imo.
http://www.amalgamatedinc.com/news.htm
I would suggest you call and talk to them (Gary Pipenger) about additives and fuel qualities. They have many independant studies published about their additives and additive blends. As with any independant tests supplied by a vendor you sort of have to read through the propaganda and look at the test results for yourself but after you do I think you will find a wealth of info and that many of the over the counter ones do not do what they say or are misleading in their wording of what they say it will do. Sorry didnt mean to turn this into a sales pitch for my additive of choice I just found their test info very interesting.
I am in no way connected with Amalgamated other than a user.
07-19-2005, 02:08 PM
#5
Registered User
Thread Starter
Roger that.
That's pretty much what I thought.
I've been using Amsoil cetane boost in the winter and Diesel Fuel Modifier in every tank.
The specs say good things about lubricity and pour point but I notice less white smoke on startup. So I figure cheap insurance and My wife doesn't complain about the smell in the morning.
That's pretty much what I thought.
I've been using Amsoil cetane boost in the winter and Diesel Fuel Modifier in every tank.
The specs say good things about lubricity and pour point but I notice less white smoke on startup. So I figure cheap insurance and My wife doesn't complain about the smell in the morning.
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