Fuel additives test in latest issue of Diesel Car ...

TornadoRed

Full Member
Aug 22, 2004
184
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Saint Paul, Minnesota, USA
craig-pd130 said:
It's fairly unscientific but they test Millers against Unicat. Both gave very modest fuel savings (from memory about 1.5% more MPG with Millers, about 3% with Unicat).

In other words, they barely (if at all) cover the purchase cost .... but it wasn't a very scientific test, just 5 or 6 tankfuls with and without, then comparing the average consumption.
Generally speaking, fuel economy depends on the BTU content of the fuel. More BTUs = traveling further on a given unit of fuel.

AFAIK, there is no fuel additive that can improve the BTU content of diesel fuel.

Fuel additives MAY increase the cetane number, slightly improving the combustion efficiency. The engine will run smoother and quicker.

Fuel additives may also lubricate the injection system and keep it clean, reducing future repair costs.

Some fuel additives either remove water or mix it so thoroughly that it cannot gel in cold weather.

To summarize: Pick an additive that does what you want it to do, and try not to spend too much per tankful. And don't expect to save fuel -- if you do, it will only be a tiny percentage.