GMScott

I used to look out for & purchase fuel with a minimum 42 cetane rating - mostly Hess and some other truck stops. Since everyone switched to the ULSD I've noticed that the Hess stations I used to stop at have changed their minimum cetane rating down to a minimum of 40.
Most places don't even post their cetane rating but I was wondering if the ULSD is ONLY 40 or can you get a minimum of 42 cetane ULSD??
With my 04.5, the difference was noticable in both performance & fuel mileage. Now that I'm going to have to NOT use any diesel addititives in the 6.7l I would like to use the highest cetane available.
Anyone know??

DBLR

I've seen some post that claim that ULSD has a Centane of between 42 and 47 but I sure don't think it does being in the wintertime my local fuel stop has 45 Centane fuel and I can tell it it a good grade of fuel by how well it runs. I think what we have now is not much more then 40 Centane based on how my engine runs and sounds. I also saw a post by Morpar1973 that said we don't need any thing over 42 Centane except in the wintertime, but I disagree being Bosch who makes our fuel system wants us to be using 50 Centane minimum like they have over in Europe. IIRC our new ULSD has less BTU's when compared to LSD so that also gives us lower mileage from our fuel.

RyeThomas

Around here all BP's are 47 cetane minimum all year round. I dont know if you have BP out your way but if you do stop by and see what the pumps say.

DBLR

The one BP I had near my house before it closed and they never did have a Centane sticker on the pump and It has been a very long time that I last saw a Centane sticker on a diesel pump any where.

TAS

What is Centane? I picked up some Power Service yesterday so I could clean the injectors. It mentioned two different mix ratios for two centane levels.

I went w/ .32oz for the 100 gal mix ratio.

BarryG

They (the feds) have been talking about changing the requirements for diesel aside from the ulsd not sure if they have. Unlike octane they dont have to display a cetane rating which I think is ridiculous. If they do it must be at least that much. Also premium diesel fuel only had to meet 3 of 5 guidelines. Lubricity, cloudpoint, cetane (45+ I think), detergency and I forget the 5th one now. So you could have premium fuel with a cetane of only 40 which is the minimum.

I also would like to find some with 50 cetane. I think the higher the cetane the higher the btu output. However it does reach a point of diminishing returns.

GMScott

I have never seen a diesel pump with a posted cetane rating higher than 45.

coobie

I ALWAYS use a fuel additive like stanadyne performance formula or primrose 405(summer) or 409(winter) year around in every tank of fuel and have done so since the truck was new.Some folks think fuel additives are snake oil,to each his own I guess.Me I am a believer.coobie

RyeThomas

Yep both BPs I use are 47 cetane. Most others stations I see are 40. I have no idea what difference it makes for everyday driving, but I have a BP card so thats all I use.

rustyshakelford

cetane is to diesel what octane is to gasoline...kinda

brett

GMScott

I'll have to check out the BP's. The last one I ever bought diesel fuel at was down in Mississippi when we were running trailers down there for FEMA after Katrina. The BP was the only place within 200 miles that had fuel - it was VERY expensive, like over $4.00/gal and my 04.5 didn't do too well fuel mileage wise. I have a 98 gal. aux. fuel tank so I started planning my fuel stops elsewhere so I wouldn't get ripped like that. I never bought any more BP. Sort of like my own personal boycott against them for taking advantage of us who were down there trying to help out.
I believe cetane is like octane in gasoline - the higher the better. That's one of the reasons for using diesel additives to boost the cetane level when you get lousy fuel.

monnshyne

This is what I just Googled up on cetane ratings and I quote:

Cetane number

The cetane number of a diesel fuel refers to the ease with which a diesel fuel ignites. Don't confuse cetane ratings with octane ratings. Octane ratings refer to the slowing or controlling of the burning of gasoline. Cetane ratings refer only to the ease or speed of the ignition of diesel fuel. High cetane numbers mean that the fuel will ignite with relative ease or that it ignites well at low temperatures.

I found this on:
http://www.procarcare.com/icarumba/r...dia_fuels1.asp

Mark