Fourtrak MPG Mix up


There are many posts here about the Turbo Diesel Fourtrak average mpg.
Trying to figure it out, I come across these facts:

Fourtrak owners report some 25 to 30 mpg (sometimes up to 33 mpg, or even a lil more???).
The number of miles on a full tank seems to average at 250 to 300 miles/full tank.
The fourtrak tank capacity is reported to be of 55 to 60 litres (14 to 15 gallons).
So with a top 300 miles on a 15 gallons tank, the mpg should be something more like 20 MPG (300 / 15 = 20). Which is about what I get on my 98 TDX Fourtrak. And nowhere near 30 MPG.
So my question is, is there a number I am getting wrong, a calculation I am doing wrong, or is everybody else getting their math wrong?

Why don't we set the Fourtrak's MPG consumption straight once and for all.
This really confuses me.



Probably because its

Probably because its impossible due to the use and modfication of the vehicles. Weather plays an important role in fuel consumption also.

Well maintained, standard vehicles can easily attain 20-30MPG, some more if they do long journeys on motorways, those used mainly on short stop start journeys will do less.
Driving style is an important factor, how many people or goods are carried in the vehicle, weight decreases MPG, is it on road tyres or off road tyres, off road tyres increase consumption.

Is the vehicle modified? if so is it carrying additional weight, or has its gearing or drag been increased by fitting larger or wider tyres, these reduce MPG. How much time is spent towing or off road, this decreases MPG, particularly if towing the heavier loads for which it was designed.

There are so many different parameters to consider, there is no real typical use as it varies considerably, so it is down to what you find your vehicle does when used in the way you use it.

our 89 fourtrack must be

our 89 fourtrack must be pretty much a worst case scenario... its only used for sub 5 mile journeys , hasnt got a thermostat... (blew the head gasket some years ago and blows the water out but starts instantly whatever the weather) so is allways running cold.. ..anyway its doing a tad over 20 mpg.... our discovery which has a thermostat and gets more normal use.often laden or towing, but rarely does more than a twenty mile run gets a tad over 30, which is where i would expect a good condition fourtrak to be...
i cant do a lot to reduce the weight i carry ,but fuel use depends on the driving style.... all these big diesels dont like high revs in low gears... i rarely use over 2000 rpm except in 5th gear... any use of the brake pedal is basically converting fuel to waste heat... looking ahead and just lifting off the throttle pedal earlier can make a large difference .

I've had just about every

I've had just about every modle of 4trak going at one time or another. I haven't had one that does more than mid 20's per galon on mixed driving. I do tend to have off road tyres on, and freely admit to a heavy right foot. However I must admit also to the opinion that if you need to worry about fuel econamy, you need to get a second car. Keep the Trak for fun, towing, etc. and don't worry too much about the MPG. In fact when I had an F80 and did 8-10,000 miles per anom I did sit down and do the math properly. It worked out cheaper to have a second car (a Cavalier as it goes) and pay 2 lots of tax, MOT and insurance, than to run the F80 alone!!! And no the Petrol is no worse on fuel than the Diesel. At least not if you drive them hard most of the time, ie the Petrol is better on fuel when being caned than the TD is when the Terbo is screaming most of the time.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.

Hi. I must admit I have


I must admit I have never given the MPG much thought, except that when on the motorway, that when the turbo is in play, aprox above 2200 revs (aprox 55mph) fuel does seem to dissapear at an alarming rate, but then one cannot allow all these new style, never offroad 4x4's to have it all their own way, and the old girl was never built as a motorway cruiser any way, and she's about as aerodynamic as a brick. Thankfully I run a veg oil mix which reduces fuel costs.

I can understand the mix up re US gallons/UK gallons would give widely differing MPG's, is the mile the same ????

Any way I am going to do a check ,out of couriosity now.

Edward (ews) '91 Fourtrak 2.8 TDX

Addition:- LaBete, did you sort your hub problem out.

Edward (ews) '92 Fourtrak 2.8 TDX


I have just worked mine out for my 98 indy 2.8td, combined it is 27 mpg which i would say consisted of a lot of short trips using A roads.

I also thought the tank

I also thought the tank holds about 50 litres. I worked out roughly that mine would do 340 miles to a tank. I actually got to 339 on the mileometer after a long journey, I was starting to worry when it went past 300 miles, but I got home for 339. I didn't risk driving to a petrol station though, I put a gallon in from the jerry can. So 50l=10gallon, 340/10=34mpg? So about 35 MPG? The route home has a few very steep hills, I don't know the tank design, but if I was on fumes it would have drawn air in and cut out? So maybe there was a few more miles in her...

Mine is a 1990 2.8 non diesel F70. I don't always drive as carefully as I could, so it might just be possible to push it up nearer 40MPG.

Anyway, hope this helps.

Do a search to find my results

I did an accurate testing of the mpg for my fourtrak, came out at 37.5 mpg, BUT!! this is my vehicle, my driving, and you have a very small margin of error with this size engine and weight of vehicle, accelerating slowly will increase mpg, harder tyres will increase mpg, road tread will increase mpg, weight loss will increase mpg, driving at constant rev/speed will increase mpg, weather/atmosphere will increase/decrease mpg,flat roads will increase mpg, lots and lots and lots of variables!!!!!! no-one will have the same mpg!!!

Full of ideas but no time to do them!!
youtube: Redfourtrack

Foutrak MPG Mix up

I understand that different conditions (driving habits, tyres size and wear, road conditions, city/highway, load...) will affect the MPG in different ways. And that is fine.
So some report up to 38 MPG on their (turbo diesel??) Fourtrak.
35 MPG on a non turbo diesel 1990 Fourtrak.
And 20 MPG on a turbo diesel Fourtrak.
Different numbers. So far so good.
But it's the calculations that puzzle me.
50 liters to a tank = 10 Gallons? What Gallon Standard are you referring to? US Gallons or Imperial Gallons?
1 US Gallon = 3.78 Litres
1 Imperial Gallon = 4.54 Litres.
So, 50 litres is about what I get also on a full tank. 13.20 US Galllons or 10.99 Imperial Gallons.
And I get a maximum of 500 kilometers on that full tank, which converts to about 310 miles.
So in terms of Imperial Gallons, I get 31 MPG
In terms of US Gallons, 23 MPG.

So maybe that's the mix up. Imperial Gallons Unit .vs. US Gallons Unit?
It's all starting to make sense to me.
Imperial Gallons?
US Gallons?


If you're trying to get an

If you're trying to get an accurate figure then don't round up. By doing so you introduce a margin of error of nearly 10%. Stick to 4.54 litres as a (UK) gallon. Unless you are trying to do the maths in your head it really is no more difficult.


Yes the mile is the same Wink but don't forget that the speedo in these things is a cable driven affair off the gear box which I reckon on mine over reads by about 8% when checked against a GPS. This presumably means the odometer over reads aswell, so there is another source of error you can factor in to the equation. Don't forget that different sized tyres will also have a similar effect but probably only +- 2-3% unless you are running 32" plus.

The only reliable way work this out is to fill the tank to the absolute brim, zero the trip on a GPS, go for a long journey, fill up again to the absolute brim and then calculate the mpg using miles from the GPS, litres from the petrol (diesel) pump and 4.54 as your lites to gallons conversion factor.