Most winter diesel fuels include some cetane. Some more than others. What I have read online most diesel fuel has about a 40 cetane number out of the pump Never really less than that. The most improvement that can be made is about 8 cetane numbers more by double dosing which gets you to about 48 cetane with 50 cetane being about the most to be used wisely. I have noticed a very pronounced better running starting and the sound of my 99 24 valve when I double dose Total Power It doesn’t die going into gear please see my recent post on that. I really only need to do this in the winter time. And then there’s the cost of doing it also. So my big question is can I over do cetane use and additive use and what would be any bad results. Also I’m open for any good discussion on cetane and it’s use. -12 f this am in Anchorage Alaska