Originally Posted By: dave5358
Fueding among product spokespersons aside, surely someone has a thought on measuring methodology for effectiveness (or lack thereof) of a fuel additive. Are we bested by an 11th grader?
You aren't going to like my suggestion, but you would never test a fuel additive's performance in the wild (but you might test other things about, it like corrosion). Just as you would never test a new type of spark plug, or a different type of fuel, or a new piston design, or anything when you are looking for the effect of one parameter.
Back when I was in school the way you tested stuff like this was with a one-cylinder test engine. You used the same fuel for all your tests and gathered your results. It was all corrected for any temperature and pressure variances. In this way, you can measure small changes
and most importantly you can attribute changes to the parameter under test. Out in the real world, there are just too many things that cannot be controlled and this will more than likely prevent you from attributing any measured effect to any specific parameter.
The only time you do real-world fuel economy testing is when that is the thing you are testing. For example, somebody may wish to compare the EPA fuel economy tests to real-world driving. In this case
what you are testing is real world driving. I found that article I referenced earlier:
http://www.motortrend.com/features/consumer/1401_real_numbers_mpg_101/
This article touches on the challenges of this test, and is where I got the 4% variance number for fuel. It was worse than I remembered though, they are claiming the difference from fuel from the same station (I thought it was from different stations). But note this test is to test real-world fuel economy, not to test some small change in some parameter for the engine.
I really think you would need a test engine in a laboratory for any decent measurements. It bugs me that an additive manufacturer would not publish any such results. Surely the have tested it like this; it isn't an expensive test. In my experience one is generally secretive about test results when they do not prove something you are trying to show.