After driving around 12000 KM's I tried various settings and combinations for optimum performance of my Logan DCi and I feel that I have found settings which perfectly match to my conditions (may be change in hill area etc), which is as given below:

Gear Shifting & RPM:

• 1st Gear - 1500 RPM - Speed 15 kmph
  
• 2nd Gear - 2000 RPM - Speed 30 kmph
  
• 3rd Gear - 2000 RPM - Speed 45 kmph
  
• 4rth Gear - 2200 RPM - Speed 65 kmph
  
• 5th Gear - 2200 RPM - Speed 80 kmph

Fuel Consumption (Average):

• In City condition 4th Gear - 2500 RPM - Speed 60 kmph - 15 kmpl
  
• In City + Highway 4th & 5th Gear - 2500 RPM - Speed 80 kmph - 17 kmpl
  
• In Highway 5th Gear - 2900 RPM - Speed 100 kmph - 19 kmpl

Few Fuel Saving Tips:

• Quickly reach to topest gear with maintaining minimum RPM of 1500
• Release clutch as quick as possible, and apply as late as possible while stopping
• Don't try to go beyond 3000 RPM, change gears if required
• Maximum speed I tried is 150 kmph but recommended is around 110 - 120 kmph
• Try maintaining speed of around 80 - 90 with lowest RPM possible
• Always maintain required tyre pressure (matters a lot)
• Its a 48kw DCi engine, so don't try to takeoff like a jet. Shift gears and cruise normally

Also I have tried branded and normal Diesel, still unable to find any difference between them. If you feel any differences do let us know.

Suggestions are also welcome about your experience, so don't wait to share yours.

PS: All figures are tested for Logan 1.5 DCi (DLS) 48kw - Diesel only, settings for petrol versions may be different.