Diesel Fuel Additives

[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