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I just finished a trip and a tank using some advice from this thread. Specifically, I throttled harder during the pulse phase. The vehicle is a, currently not very aerodynamic, diesel pick-up truck with manual transmission. The engine puts out some serious torque in a 1000 rpm band so the truck accelerates quickly even in steep inclinations when flooring it. Therefore I used p&g consistently even in inclinations despite the gliding phase suffering. Previously I used to keep a steady speed uphills.
Anyway, the net result was a very good improvement. I got 6.5 liter/10 km one way and 6.0 the other way. Previous figures for this run was about 7.4 when driving with a gasoline style p&g. For comparison, running on cruise control yields 8.7.
Now the question:
Since this vehicle is "a brick" and does not glide well, there are a pretty large number of acceleration phases for a given distance. The engine and turbo is larger than your average car so the turbo lag is significant. It takes a couple of seconds until the torque wave kicks in, especially in highest gear. This means I am flooring it without getting much in return a lot of the time.
Is this really the best way of applying power?
The built in fuel meter only averages consumption over longer time so I can't study this in real time. Anyone with knowledge on modern diesels that can say something about the typical engine mapping and efficiency before the turbo starts producing?
Should I gear down to reduce lag and have shorter pulses? (more rpm and transmission losses and more wear on tyres etc.)
Should I apply power more progressively and not floor it at once?
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