N52 3L mpg

One trip meter possibly with no navigation but definitely two with. The second one only comes up on the screen but not the instrument display.

I've tested the trip computer and it's usually within the next reading it jumps to so is accurate. A long, long term average will give an even truer picture but I like to reset mine each tank to keep an eye on it, helps spot any problems earlier. I pretty much know the longer term result as I know what I get each time, which is about 30.5-31.5.
 
My long term average is 32. Best long trip was around 43 measured at the pump with 18" wheels. Very boring I must admit. Roof down knocks off about 7% but worth far more!

High gear and low rpm without lugging is the best. The M54 engine can manage a 6th gear 1krpm cruise on the flat. Low rpm and high load creates the least amount of pumping losses and friction losses. Higher rpm with minimal throttle means pumping loss is high, as the engine is pumping a vacuum against a closed throttle plate, plus the engine is spinning more for the same distance travelled, both reducing efficiency.
 
EdButler said:
My long term average is 32. Best long trip was around 43 measured at the pump with 18" wheels. Very boring I must admit. Roof down knocks off about 7% but worth far more!

High gear and low rpm without lugging is the best. The M54 engine can manage a 6th gear 1krpm cruise on the flat. Low rpm and high load creates the least amount of pumping losses and friction losses. Higher rpm with minimal throttle means pumping loss is high, as the engine is pumping a vacuum against a closed throttle plate, plus the engine is spinning more for the same distance travelled, both reducing efficiency.

What does that mean in layman's terms? I don't speak car... :P
 
It means the engine has to pump air through it and the more times it spins round in a minute the more air it has to pump through it, which uses energy. Spinning faster also means the pistons travel further and they have frictional losses sliding up and down the cylinder bores. Slower engine speed equals less friction and more efficiency. Try sucking lots of air through a straw (closed throttle plate) compared to sucking it through an open mouth. One is a lot easier than the other...

It also means I was right when I said you can run 6th at 30mph on a flat surface no problem. I've driven our 330i Touring with the same engine as my Coupe, longer gearing and an instantaneous fuel consumption gauge which clearly showed changing up to 6th used less fuel.
 
very interesting @EdButler and @Steve84N for the 'translation' haahaha. Makes a little more sense.
 
Inspection II last Thursday and the MPG has increased from the 24/25 mpg.

Filled up on Friday and the apps were showing 25.38 mpg from the last fill up to this one.

From that fill until today I've done around 130 miles with about 50 of those being motorway speeds.

The car is now showing 27.7 mpg with the highest readout for the first 30 miles of 36.6 mpg and that was around town.

Will see what it's like after a week of going to work and back.
 
So my latest was showing 27.6mpg on the OBC when I collected it.

Drove 100+ miles home, did another 80 miles then a 400+ mile round-trip to Cheshire and the average speed has gone up to 28.8 from 25 ish and mpg is now showing 29.1!

So it seems higher average speed means better mpg! :evil:

Suits me just fine!
 
Mr Tidy said:
So my latest was showing 27.6mpg on the OBC when I collected it.

Drove 100+ miles home, did another 80 miles then a 400+ mile round-trip to Cheshire and the average speed has gone up to 28.8 from 25 ish and mpg is now showing 29.1!

So it seems higher average speed means better mpg! :evil:

Suits me just fine!

Pretty much what i find too. 50mph seems best mpg so far. Havent tried 40mph but dont think i could consistantly do that on the motorway.
 
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