I aint sure on this .......need someone that knows ya know"give:

yeah this is gonna get interesting i think. :pc::numb:

so in the winter cetane boost is a bad thing is that what you are saying WHITMOORE. I thought that cetane helps burn the fuel better for less black smoke and moore power

Someone correct me if I'm wrong, but I thought cetane was the burn rate of fuel?

The BTU content probably varies from one to the other, but I think the main reason they seem to "work" is they make the rate of burn faster...

steved

You are exactly right and I don't know all about winter blend fuel having higher cetane rating causing poorer milage. What I do know is the ambient temps outside will effect milage of your diesel. I drive from OK to MN in December for christmas and it could easily be 60* here when i leave and I"m getting around 17 mpg...as i approach MN, the temps are closer to 0* and I can't get above 13 mpg....and its all the same fuel....i left OK with 130 gallons so i didn't have to buy any fuel untill my return trip.
Then when i return to warmer climates, my milage returns. This is a simple observation but it was consistent with temps and seemed like for ever 25* drop in temp, i lost about 1 mpg.
My best milage comes in the summer when its 90*-100*... I get 18-19 mpg then.

I cant really tell ya thats why I said we needed someone who knows whats going on here

your still speaking as if cetane is an ingredient in the fuel, like an additive, it is not. It is a rating system or value of that fuel that tells you the burn rate.
Certain other things such as kerosene cant be added to diesel to give it a different cetane rating.

I've left PA at -25*F getting 12mpg...ended up in NM getting over 20mpg. I know all about that temperature thing! :U:

And another thing that completely makes this a moot point is the fact that suppliers add their own concoction of additives to the fuel they put out at the pumps...so we might not even see the effects of the fuel itself, but the additives within that fuel.

steved