I started eco-driving only since a few weeks on my manual 11 years old diesel, so I don't have a lot of data to backup my saying. As I have a diesel I tried to change gears before 2000rpm, but then I was under 1500rpm and the ICE wasn't happy...
Before eco-driving I was using half low-grade and half mid-grade diesel. I changed to high-grade diesel and felt a noticeable change after half a tank : the ICE wasn't so unhappy to be under 1500rpm. After 1.5 tank, now the ICE can accelerate from 1200rpm
High-grade diesel contains different additives than mid-grade and this is certainly a better cleaning additive that is permitting my ICE to run better at lower rotation. Even if high-grade is 6% more expensive, I calculated on the first tank each km cost me 9% less
Currently these two high-grade tanks are permitting me to have a better mileage, but these are in fact doing a better/complementary maintenance than my mechanic is doing.
In a few tanks I will come back to low/mid-grade diesel and monitor how the ICE runs at 1200rpm to know when to have a couple of high-grade tanks.
Have fun,
Denis.
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