when should i put it in 6th?

[jaz205gti]

Here’s a bit of a strange one when driven on the motorway Im always messing with the trip comp iv notice when having it in 5th at around 60 it does more mpg than when I have it in 6th how is this possible? its ticking over about 1.5k in 6th and just below 2k in 5th does the turbo play a part in this ?
When should I be using 6th?

 

[attila_tdi]

I'm guessing that's when you come up to a very light slope (usually not even noticeable). You can be doing a lower rpm in one gear and have a higher fuel consumption.

If you google "brake specific fuel consumption" and have a look at the images you can see the roundish area graphs which shows fuel consumption can be higher at lower engine speeds.

I've noticed it too on mine, I have used 6th at mid 40s on a flat and its fine...until it hits a slope.

 

[DEAN0]

Here’s a bit of a strange one when driven on the motorway Im always messing with the trip comp iv notice when having it in 5th at around 60 it does more mpg than when I have it in 6th how is this possible? its ticking over about 1.5k in 6th and just below 2k in 5th does the turbo play a part in this ?
When should I be using 6th?

I expect you will find that you are using less throttle in 5th than in 6th at 60.

I find that i get better economy round town if i stick to 3rd in 30 zones rather than 4th.

The throttle on the modern diesel is basically a fuel pump - the more you press it for a given speed the more fuel you put in.

 

[techathy]

At 1500 rpm you'll be making very little torque so putting a high load on the engine compared to the available power, this pushes the fuel usage up. Not only that but throttles are mapped to give a perceptive linear throttle response, this means a small input at low rpm could deliver you the equivalent of 70% or 80% butterfly opening on a petrol engine.

 

[chris4500uk]

I personally stick it in 6th when doing a steady 70mph or above (on private roads)