One of the reasons I asked that was Fuel Quality. If you have a good local supplier, then it's fairly easy to stock your tractor with decent fuel. Unless you are pulling a tanker, you have no choice but to deal with variable fuel supplies while driving long distance.
But I can read and I do value objective experimental evidence and discount anecdotal evidence.
It's not clear to me to what extent you have worked on fuel systems. Did you understand the significance of what I posted in #116 ?
What I read is that companies like Cummins (I do believe they produce at least a few road-going diesels) specifically recommends against using additives. I read that BMW specifically recommends against consumer additives and at least for some diesel models has a sticker on the fuel door telling you not to add anything to the fuel.
Perhaps not BMW, but Cummins would have been signatory to the EMA letter calling for a lower wear-scar limit in diesel fuel than what Big Oil bought in Washington. Do you understand the technical significance of this trade-off ?
There are bad practices still out there today. I for one, would never dump ATF into a fuel system; but there are people that still persist in dumping ATF into $100,000+++ machines. Organizations and many individuals like simple, lowest-common-denominator rules. Mostly, corporations are run by Finance and Legal Depts - They alone have enough clout to drive a No Additives edict, attaining the Lowest-Common-Denominator ease of warranty denial.
I can also "read" the utter lack of compelling experimental data on either MPG or longevity published in reputable engineering journals to support the claims of additive makers.
Nothing wrong with "reading", it is ONE source of useful information, and I do quite a bit of it myself. But, I also do my share of wrenching, and talking directly (in the real world) with diesel mechanics and injector repair shops.
Speaking of reading - Did you read what I've already posted ? I have zero expectation/requirement for MPG increase ! As long as an additive does not decrease my mileage, I DON'T CARE !
If you insist.... let's break that down...... Do you understand how life tests are done ? A manufacturer will use calibrated reference fuel, from a top tier supplier. Perhaps you do, but I don't have access to that kind of fuel. Lab tests and real world performance often differ.
Do you understand how injector performance degrades with deposit formation ? While some additives will change the combustion characteristics of fuel, mileage claims (again - which I don't care about) mostly relate to cleaning action. If you use an additive on a brand new vehicle, will you see a magic 5mpg increase ? Of course not. Put 130,000 miles on that same engine with varying quality fuel sources - chances are there are mpg affecting deposits in place that need cleaning.
One popular additive claims 8% improvement in MPG? Do you believe that? Why? Do you generally just accept uncritically or with anecdotal evidence the marketing claims of business? If so, PT Barnum has something he'd like to sell you.
There are other good additives out there, but to name one..... Do you understand what business Stanadyne is in ? The are a huge supplier of fuel injection hardware components. Do you honestly think they would jeopardize their profits in that business sector and risk long-term damage to their reputation by supplying additives that would cause harm to injection systems, or at best Do Nothing ?
Some people (like the OP) are looking for ways to improve the longevity and reliabiltiy of the expensive machines they own. I've done my research, made my choices, paid attention to the results I've achieved, and been happy with the performance of what I've used for additives.
I've worked in and with a lot of technical organizations. Out of all those people, I'd only put 5 of them on a Trusted list. And, even they only get Trust, but Verify. So No, I'm not an Easy Sell.
Some people hang out in threads like this to Listen, Think, and Learn. Other people show up with different agendas.
Between the Schizophrenic Thread Drifting, and the Non-Listening-Rhetoric-Spouting-Aspersion-Casting that's going on here, I dropped out of this thread for a while. Probably will again, as it's reminding me too much of the FP forum, instead of a technical one.
Rgds, D.