Poor fuel economy 80 series Landcruiser

Q. I’m a recent convert to the ways of diesel having sold my 1FZ-Fe 80 Series LandCruiser due to growing petrol prices. I ended up spending a total of $3000.00 buying a 1HZ 80 on top of what I sold my old 80 for – pretty good to basically have an engine swap for $3000.00 I reckon! Even better, the new truck has less kilometres on it, so I’m happy. I’ve swapped all my gear over to it, including bullbar, rear Kaymar bar, roofrack, drawers, winch, dual batteries, water tank, etc. My question is; I’m not getting any better than 15L/100km out of the  engine, and because I literally drove it home and started fitting my gear to it, I haven’t been able to tell if it’s the accessories that are doing it or not. I haven’t put it over a weighbridge yet but the old 80 tipped the scales at just on 2,700kg in ‘street trim’. Is this poor fuel economy for this motor, or normal? It has 240,000km on the clock. 

A. Weight is such an overlooked item in the world of fuel economy. And tyres just magnify that problem. If you don’t know the condition of the fuel injection system it may be a good idea to start with a good tune up and injector work. Just to be sure it’s running clean under load. Now the formalities are over let’s start looking at what you have bolted on. We have our own weigh scales and regularly we see 4WDs tipping 3300kg and higher in ‘equipped up’ form. This adds to sheer rolling resistance on the tyres and does help going up hills. Tyre size is a BIG issue and our dyno consistently shows a power loss from as simple as going from 265/70-16 to 275/75-16 losing 10% in power and torque. Last is suspension….if it’s been lifted very high this can also add to wind resistance. As a guide I might ‘suggest only’ that 12-14 L/100km would be ok and any higher is getting heavy.