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NAVARA D40 - Whats going on with my MPG?

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813 views 9 replies 8 participants last post by  Davipon  
#1 ·
What on earth...

So, highest mileage I've uncomfortably got from my d40, is 427 miles (UK).

Now... here's an example tally of my recorded miles per £ or Litres of fuel:

£10 @ £1.39 p/l - 7.148 litres- 55 Miles.
£15 @ £1.41 p/l - 10.135 liters - 96 Miles.
£20 @ £1.38 p/l - 14.54 litres - 136 Miles.
£40 @ £1.38 p/l - 28.8 litres - 169 Miles.
£102 @ £1.38 p/l - 76 litres (full tank with leftovers) - 427 miles.
£102 @ £1.42 p/l - 71.78 litres - 360 Miles.

Yet... at 80litres, full tank, I average get 380-400 miles of mixed driving. Similar routes every day, various lands but never anything above 100kg, or towing. Same tyre pressures, average temps for this year.

I was thinking maybe the weight of 80l of fuel is reducing the MPG - however the calculations that come out range on average of 27-29mpg regardless of load/drives. It seems anything above 25 litres, the usage plummets?

If I'm getting 50-60 miles from £10 of fuel, at an average of £1.39 with 7.14 litres. X 10 that would be 500-600 miles @ 71.4 litres of fuel?

Confusion??

Cheers

John
 
#2 ·
These things are not bought for fuel consumption i don't check much anymore as they are quite poor on fuel consumption but i know i use about £20 a week for about 100-120 miles a week driving to work mostly through lanes i am happy with that as was using more but have changed scv,maf etc and i see less unburnt fuel(black smoke) out the back now
 
#3 ·
I used the Fuelly app for a couple of years, full tank to full tank, to track my mpg. I found a consistent 28-29 mpg regardless of driving style, once or twice got 31 or 32 on a long motorway run if I kept to 70. I was a little upset about this as when I bought it the manufacturer was quoting something like 41, a complete and utter lie.
 
#8 ·
My 22 year old D22 always averages 37mpg, I once got just over 40mpg!
Things I have done to up the mpg's.
Remove cooling fan
Fit free wheel hubs
Block EGR
Fully synthetic gearbox oil
Truckman top, you'll be surprised how much drag an open buck body generates!
Ensure tyre pressures and wheel alignment are always correct, 1/2" out on WA is the same as dragging the truck 90' sideways for every mile travelled!
Probably a couple of other things done, I have forgotten in
 
#9 ·
Now I have fixed the engine issues I had when I bought the Navara, i have done the following and get 450miles to 60ltrs of fuel ( 32mpg) running around locally. Not done a motorway run yet.

2007 plate 6 speed manual 145000 miles on the clock

New turbo
Boost control solenoid ( 1st boost control solenoid packed up after 4000 miles)
suction control valve
Recon injectors
EGR delete
New road tyres to replace the horrible all terrain tyres that were so noisy
try to keep the revs below 2000rpm.

Hoping to get 40mpg on the trip to south of France later this year.

It does have a snug top fitted

Better than my shogun this has replaced