Diesel Fuel Additives

[billferg]

Is there any statistical analysis to support the cost effectiveness of fuel additives for diesel engines? Thanks for your response.

[More Power]

Yes, but that data was produced by manufacturers of the fuel treatment. There have been quite a few independent tests (magazine articles, individuals, web sites, etc.) that fall more into the category of anecdotal. It would be a big and expensive undertaking for even a magazine budget to produce a scientifically valid - statistically valid fuel treatment test that measured fuel economy.

I remember reading the results of fuel treatment tests produced by various fuel treatment manufacturers some years ago, where they evaluated fuel economy changes in fleets of diesels over many months (statistically valid) - some of the trucks ran with fuel treatment and some ran without (control group). They saw a few percent increase in fuel economy when using a fuel treatment that included a cetane improver.

Individuals have a much harder time seeing a fuel economy change because an individual just doesn't burn enough fuel over a short enough period of time. Changing conditions through the seasons and changes in vehicle operation (summer towing - winter grocery getting) question the validity of the data.

Jim

[Mark Rinker]

My conclusion (based on lots of miles, and lots of different additives tested) is that if you are looking for increased mileage / fuel savings to justify the expense - save your money.

However, the cost of fuel injector replacement in most modern diesel engines is high. It seems plausible to me that a fuel treatment regimine can extend the life of fuel injectors, and in the case of certain types of injector failures, even your piston crowns. Have most definately seen additives WORK to free injectors that were sticking and decreasing power and mileage. free up, clean up exhaust, and return mileage to normal.

Most over-the-road drivers swear by the stuff. Howes, Lucas, FPPF, Diesel Kleen...who knows...makes you feel good when you add it and go down the road, that I know because I have burned all of them at one time or another.

Never found one that measurably increased mileage. Never found one that wasn't expensive. Never found one that grew new hair on the top of my head.

Personally, I like Howes. Can economize when rolling on lots of miles buying a big jug, its formulated to be added in greater quantities / gallon of #2 than some other products, and to me that equals more likely to get correct and consistant mix when treating ~34 gallons of fuel at a time. Howes looks, smells, and feels like something that should burn in a diesel. See lots of it going into the big rigs. Seems to keep my Duramax injectors happy - but again, who knows.

[JohnC]

Mark's experience not withstanding, when I had my 6.5 I did tens of thousands of miles of comparison testing of Stanadyne additive and the conclusion I came to was that it netted a 5% mileage boost, just enough to offset the cost of the additive.

YMMV...

[Kennedy]

I run FPPF Total Power in all of my diesel fuel. Wouldn't have it any other way. The primary benefits are fuel system life and combustion. Minor MPG gains help offset the cost which is just pennies per gallon of fuel treated.

I buy my fuel 500 gallons at a time and store in an outside storage tank. I run Amoco Premier #2 non winterized whenever possible and treat myself with FPPF. My present batch is the afformentioned blend, but I'm getting low and will have to buy some winterized fuel by the looks of it....

[MacDR50]

Is a cetane improver required? I have read so much about this topic I am pretty much befuddled by it all. Some point to low cetane levels in ULSD, I have been told that Ford recommends a certain cetane level that is higher than that found in most USLD. I read that cetane levels are different based on whether you buy fuel that meets Canadian versus US specs.

What does GM say? After all they warrant the engine.

[More Power]

From a piece I wrote a while back....

"Opposite to octane, a cetane rating indicates a diesel fuel’s level of combustibility. A higher cetane number is generally better – better for cold starts, less smoke, more power, a small bump in fuel economy and less combustion rattle. ASTM D-975 currently sets the minimum cetane level at 40. Bosch tested diesel fuel around the U.S. during the summer of 2002, and found a cetane range of 44 to 57, though low forties are commonly reported by others. By comparison, Bosch found European diesel fuel tested at 51 or greater during the same period.

Commercial diesel fuel additive manufacturers offer products that improve the cetane rating by up to four numbers. While they closely guard their formulas, we know the compounds amyl and hexyl nitrates have been used to improve the cetane rating in diesel fuel."

As far as GM is concerned - and to answer your question, as long as you're using ASTM certified diesel fuel (commercially available pump diesel) you're fine as far as fuel quality in general and cetane in particular are concerned.

Jim

[Mark Rinker]

My conclusion (based on lots of miles, and lots of different additives tested) is that if you are looking for increased mileage / fuel savings to justify the expense - save your money.

On re-read, I failed to make the point originally intended...that is, adding fuel injector cleaner to each tankful is unlikely to provide a sufficient increase in mileage for that tankful, to cover the cost of the additive. However - adding cleaner over time is likely to keep injectors spraying freely, and avoid situations where mileage is negatively impacted, or lifespan of injectors shortened.

Bottom line - I am a believer in (quality) fuel treatments, but its very hard to measure your ROI in a repeatable or meaningful manner.

[DmaxMaverick]

As indicated above, short-term testing is of little value. However, in the long-term, mileage records can be very helpful to determine the usefulness of additives, from an economic point of view. I have used various additives, and combinations of additives, in the same vehicle (2001) over more than 100K miles. My conclusion is (and has been for over 10's of thousands of miles now), the additives I use do, in fact, pay for themselves, monetarily. I cannot attest to any component longevity advantage. That would require a fleet of like vehicles tracked over their lifetime with meticulous record keeping.

For a couple years now, I have been using Power Service (gray bottle) and Supertech (Walmart) TC-W3 two-cycle oil (formulated for liquid cooled engines, as opposed to hotter air cooled engines) at about 8 oz. each per tankful (20-25 gallons). I can see, feel, and hear a difference if I don't use either or both of the additives. The engine is more quiet, smoother, more responsive, and returns better mileage. Period. YMMV, but in my case, it's obvious to me.

[Mark Rinker]

>>> I can see, feel, and hear a difference if I don't use either or both of the additives. The engine is more quiet, smoother, more responsive, and returns better mileage. Period. >>>

Here is a reasonably scientific test - for illustration's sake:

1) Take two brand new, identically equipped Duramaxes off the assembly line, one that will run treated #2, the other to run only 'plain' #2 as a control;

2) We then take 50 Duramax owners (members of TDP perhaps), have them take each truck home for a week of varied driving, cold starts, etc., and after using both trucks - record the one that they believe was running treated fuel;

Hypothesis #1: ~25 would pick truck 'A', and ~25 would pick truck 'B' +/- 5%.

Hypothesis #2: The truck running treated fuel would average slighly better MPG over the entire test period, but its total fuel + additives bill would be higher than the truck running only straight #2, when adjusted for any variance in miles driven between both trucks.

Hypothesis #3: The truck running treated fuel, if these tests were extended to include (500 drivers * 2000 miles) = 100K miles, would be less likely to develop a 'stuck' injector, or encounter injector failure, while the control truck would be more likely to encounter decreased mileage at some point, or even stuck/failed injector(s).


Again, even with a control - its easy to see that BIG variances in driving by the 50 or 500 members, temperatures, terrain, and countless other factors would make an accurate, scientific test difficult if not impossible. With only one truck, its nearly impossible for any individual to make any scientifically sound conclusions - as there is no way to test against an accurate control...

[JohnC]

Gee, all I did was drive the same boring route day in and day out, day after day, week after week, month after month... and record every drop of fuel that went into the engine. My mileage calculations from tank to tank were remarkably consistent. Then I started using the additive and repeated the same process. I think I threw out tanks where I was on a long trip. Probably 20K miles without and 20K miles with.

[Mark Rinker]

- Were the 20K mile tests conducted during the same months, with the same weather? How many gallons of winter blend fuel were burned, vs. regular #2? Same fuel station? Same fuel quality and source throughout the entire 40K test?

- Every Duramax I've owned has recorded slightly better mileage, the older it got - as long as the injectors were in good shape. Never saw >20mpg unloaded with the 2002 until it was on the second set of injectors and nearing 200K miles on the clock. How could this observation effect your results, using your "20K without treatments, 20K with" method, as a control group - especially if you started the tests when the truck was relatively new?

- If you drove your truck 20K miles without any additives, its likely you then had deposits forming - that were lowering your mileage. Start using additives - and you will likely find your way back to your engine's MPG potential, in a few tankfuls. What if you could maintain your mileage potential by adding only one bottle every 3rd tankful? 5th tankful? Only when you begin to see a consistant, repeating decrease in mileage...?

IMO - Meaningful controls for an accurate test of fuel additive ROI are impossible with one truck - or even a fleet of 'similar' trucks.

[JohnC]

a) It was a 6.5, not a Duramax

b) The test was over several years. The truck had 28,000 miles when I started. For the first two years or so I did not use an additive. Then I used Stanadyne for at least the next two years, winter, spring, summer and fall. I did not stop using it. Fuel came mostly from one station over the entire period. Routes and conditions were almost always the same. I recorded every drop of fuel and what type of driving. My mileage was consistent and repeatable. I got (IIRC) 5% better mileage with the additive; just enough to cover the cost of the additive.

c) If the additive was reducing or preventing deposits, so be it. The mechanism is immaterial; the results speak for themselves.

d) I feel it is easier to get meaningful results with one truck doing the same thing over the same routes with the same load day in and day out than with a fleet of trucks driven by different drivers and pulling different loads to varied destinations.

e) I am a trained scientist with a BS, an MS and even an Associate degree, and am familiar with the scientific method. I have confidence in my results.

QED

[wmholden]

Today's diesel has horrible lubricity and one should always use additives in EVERY tank. "If you're running a diesel and you ain't putting something in your fuel you're an idiot" - owner of Turbo Shop in Louisiana. He rebuilds injectors for a living and has done so for decades. So I pour that cheap ($15 per gallon) red stuff in my LLY at every fill up. So far so good.

[trbankii]

Cheap red stuff? Considering that off-road diesel is typically dyed red, that could get you in trouble if anyone is checking for such things.

[Kennedy]

[EdHale]

I've been using Total Power ever since my truck was zero miles. It now has 191,000, runs great, 19-20 mpg when not towing and I've lost one injector in this entire time. So I'm a believer in the product, but what is the difference in the "Deluxe" version? My remaining stock isn't "Deluxe" as far as I remember. I buy it a case at a time and lasts me a long while. It was purchased from you also.

I guess it might be Deluxe and I have been using it for so long I don't remember.

[Kennedy]

I don't know that there is any not listed as deluxe, but if so it's just marketing.

[EdHale]

I have been using it for so long John I just don't look at the label anymore I guess. A case lasts me a long time now that I'm retired. When a bottle is empty I just grab another one off the shelf and keep going.

Thank you for keeping me supplied for all these years as well as with filters, etc.