Power Service vs. Pri-D Additives

litton · **Posted:** Thu Feb 22, 2007 7:41 pm

I've been bouncing back and forth between these two additives for ~3,500 miles. Most of the fuel has been ULSD and I can definitely hear a difference. The engine runs much quieter with the Pri-D. No noticeable difference in mileage.

I have no idea what makes it rattle less and I have no idea which is a better additive. Just thought I would toss this out. Perhaps some informed individual can enlighten me on the significance of "less rattle" in a diesel.....aside from the obvious of being less noisy. :twisted:

Some one was bound to say that. :twisted:

Is this a good, bad, or indifferent thing?

oldnavy · **Posted:** Fri Feb 23, 2007 9:05 am

litton wrote:

I've been bouncing back and forth between these two additives for ~3,500 miles. Most of the fuel has been ULSD and I can definitely hear a difference. The engine runs much quieter with the Pri-D. No noticeable difference in mileage.

I have no idea what makes it rattle less and I have no idea which is a better additive. Just thought I would toss this out. Perhaps some informed individual can enlighten me on the significance of "less rattle" in a diesel.....aside from the obvious of being less noisy. :twisted:

Some one was bound to say that. :twisted:

Is this a good, bad, or indifferent thing?

The ULSD is what is making the engine quiter most likely since most ULSD will be 46 cetane or higher. The additives are going to just help with lubrication of fuel system and some will help raise cetane levels, but not if supplier has already boosted the fuel with a cetane improver. I would stick with the ULSD and see how quite it runs, remember it will take a couple of tanks to get the LSD completely out of the CRD's system.

litton · **Posted:** Fri Feb 23, 2007 9:10 am

As I noted initially, virtually all the fuel I get is ULSD. No, there appears to be a differance attribitable to the additive. Of course 3,500 miles isn't that much....only 8 or 9 tanks so I'll keep alternating.

oldnavy · **Posted:** Fri Feb 23, 2007 9:27 am

litton wrote:

As I noted initially, virtually all the fuel I get is ULSD. No, there appears to be a differance attribitable to the additive. Of course 3,500 miles isn't that much....only 8 or 9 tanks so I'll keep alternating.

You don't understand, you can't be alternating and see the difference. The reason is if you fill up with LSD, then run tank down to 5 gal and add 15 gal of ULSD you do not have ULSD of 15 ppm sulfur, you have 100 ppm plus fuel and may have mixed 46 cetane fuel with 40 cetane fuel which may drop your fuel to 42 cetane and with that come the rattle. This is the reason that the government requires the fuel station to wash his fuel tank out with several loads till the testing shows that the fuel has become 15 ppm or less.

litton · **Posted:** Fri Feb 23, 2007 9:40 am

I guess I didn't make myself clear....I have been running ULSD, it's the additive I've been alternating. Perhaps one tank of the 8-9 has been LSD and that was quite some time ago.

BVCRD · **Posted:** Fri Feb 23, 2007 9:50 am

litton wrote:

I guess I didn't make myself clear....I have been running ULSD, it's the additive I've been alternating. Perhaps one tank of the 8-9 has been LSD and that was quite some time ago.

Mine hammers more on ULSD without ANY additive.

tulsa · **Posted:** Fri Feb 23, 2007 11:27 am

oldnavy wrote:

litton wrote:

As I noted initially, virtually all the fuel I get is ULSD. No, there appears to be a differance attribitable to the additive. Of course 3,500 miles isn't that much....only 8 or 9 tanks so I'll keep alternating.

You don't understand, you can't be alternating and see the difference. The reason is if you fill up with LSD, then run tank down to 5 gal and add 15 gal of ULSD you do not have ULSD of 15 ppm sulfur, you have 100 ppm plus fuel and may have mixed 46 cetane fuel with 40 cetane fuel which may drop your fuel to 42 cetane and with that come the rattle. This is the reason that the government requires the fuel station to wash his fuel tank out with several loads till the testing shows that the fuel has become 15 ppm or less.

oldnavy,
Is ulsd 46 centane including Shell? What is the range for USLD and LSD? What is the max centane obtainable using Power Service?
Lewis

DarbyWalters · **Posted:** Fri Feb 23, 2007 11:27 am

I think oldnavy is correct about additives and ULSD...they don't raise the cetane level beyond the already improved 46 (or whatever the higher level currently is at). They used to work on the old LSD but not the newer ULSD. I think some BioDiesel is the best additive to quiet down the CRD...just not available in San Antonio...I have to go to Austin to get any right now. Just wish we could get 50 cetane with a B10-B15 blend :twisted:

oldnavy · **Posted:** Fri Feb 23, 2007 11:47 am

tulsa wrote:

oldnavy, Is ulsd 46 centane including Shell? What is the range for USLD and LSD? What is the max centane obtainable using Power Service?
Lewis

When making ULSD the process leaves the final fuel product about 50 to 54 cetane, but trucking industry wanted it to be 42 and auto industry wanted 50 cetane and it was settled at 46 cetane then when put to finnal print the refineries could sell it as low as 40 or 42 under some conditions. I don't think we will find much of the ULSD under 46 cetane as the cost goes up to drop the fuel cetane level back down. I never understood the trucking companys demand for 40/42 cetane over the higher cetane that is cheaper, only thing I could thing why trucking industry wanted lower cetane was bad info.

Power Service vs. Pri-D Additives

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