Hilux Fuel Efficiency
last updated 22/03/2016
Fuel efficiency is an important parameter when camping or touring. Fuel is one of the biggest costs of any camping trip so keeping it down helps free up significant beer funds. It’s one of the reasons I chose the Hilux. Many people are disappointed when they find out what their fuel consumption is with a loaded vehicle, stuff on the roof and towing a trailer or caravan. Unfortunately the laws of physics are a harsh mistress, and you can’t add weight and a wind resistance without consuming more fuel. When touring we average around 11L/100km – this includes significant offroad work and highway cruising speeds of around 90 to 100km/h. Most trips include some level of offroading so I don’t have a figure for highway only. Our worse tank was around 12.0 and best was around 9.5. Not bad considering what those towing a trailer or caravan are reporting from our conversations with them. A chap driving a big American ute towing a 5th wheeler reported around 33L/100km. Big four wheel drives with big caravans are getting 17 to 25L/100km, depending on variables such as type of vehicle, cruising speed etc. A Mitsubishi 4 cylinder turbo diesel was getting 14L/100km towing a large van at 80km/h. A turbo diesel Prado towing a camper trailer was getting around 13.5L/100km cruising at 100km/h. The best figure we’ve heard was from a fella traveling by himself driving an old Navara 3.2L normally aspirated diesel, towing nothing. He says he got 9L/100km cruising around 90-100km/h. Not towing anything does compromise space and comfort, but the returns are better fuel efficiency, reduced wear, increased mobility and less risk when going off road.
My vehicle has around a tonne of gear in it when fully loaded with fuel and water (that’s a literal tonne not a figurative tonne). The load on the roof rack and the roof top tent has had a significant effect on fuel efficiency, especially at higher speeds. Cruising above 100 really blows out the efficiency. At 110km/h I used to get around 9L/100km, now it’s more like 13. I prefer to reduce speed a bit – it’s better for the environment, better for the car, reduces tyre wear, reduces the stress related to driving aggressively and overtaking, saves fuel and gives you time to take in the scenery and think about what sort of beer you’d like to spend your fuel savings on at the next roadhouse bar.
I tested instantaneous fuel efficiency at various speeds on a straight and level stretch of road on the Nullabor in Western Australia. The wind was calm, the airconditioner was off, the windows were up and the elevation was 40m above sea level for the entire test. Vehicle tested is a 2007 manual dual cab Toyota Hilux SR5 3L turbo diesel (D4D). These figures are from the trip computer so accuracy is rough but still provides a good indication of how fuel consumption quickly escalates with speed.
Look at the jump from 100 to 110km/h – just an extra 10km/h consumes an extra 2.3L/100 or around 22%. At 60km/h, the motor is revving very low, well below optimum, and is so lightly loaded there is probably a greater proportion of engine power running engine overheads compared to that being used to move the vehicle. Not an efficient way to run the engine, using only a small portion of rated power. Regardless, wind resistance dominates so much that 60km/h is far more efficient than higher speeds. The effect of wind is even more pronounced if towing something. That’s why you sometimes see people towing stuff cruising at 80km/h.
So at 60km/h, fuel consumption is about half that at the speed limit. Halve my fuel costs by going 60? It’s tempting, but might be a bit annoying to other motorists, and annoying to myself considering the nagging I’d get. I hover close to 100 most of the time, but I can break the 10L/100km barrier by sticking to 90.
Our best fuel economy whilst fully loaded for touring was 9.5L/100km. It included a couple of hundred kms of gravel work and some slow four wheel driving in and out of dry creek beds on our way to Whistleduck Creek in the Davenport Ranges. The rest was tarmac cruising at 90km/h, apart from the drive from Mataranka to Darwin where the wife got cranky and we sat on 100km/h. Mind you there was a tail wind at time. In any case it’s good to get under 10L/100km.
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Hi Joe, I also have a D4D Hilux (06 model) which appears to be set up similarly to yours with canopy, steel bulbar, winch and homemade drawers. I also have a longranger fuel tank for those longer trips. I recently weighed it with a full tank of fuel and some of my basic camping gear and it came in at 2620kg, only 100kg below the GVM. With the rooftop tent, all our gear and the extra person, it would be way over its GVM. Towing the camper trailer we get around 13 – 14 l/100km and fully laden with 2 teenagers as well on the return from our recent Cape trip it blew out to17l/100km. I am amazed at the economy you are getting from your vehicle. One thing I picked up in one of your articles was about the manufacturers detuning the engines to meet certain requirements. Regarding the Hilux, I often wonder why the same motor in the Prado produces a higher Torque right through the range compared with the Hilux and why we can’t do the same in our vehicles. I would imagine with a loaded ute this would be a big advantage, especially when towing.
Hey Gordon your economy aint too bad considering load and the fact that you’re towing, consistent with what I’ve heard others getting for similar arrangements. Bigger 4WDs / petrols would be getting 17 or more rather than 13. The blowout when offroading is normal, especially if you’re towing. When towing offroad the difference is amplified since you burn through so much fuel accelerating the mass of the trailer whenever you accelerate and slow down for obstacles. Remember I’m not towing and I drive pretty slow to save fuel. Yes it’s easy to go over GVM when a few accessories and camping gear are added. Some vehicles with every bit of bar work and rock sliders, bash plates, racks, drawers, lighting, steel rims, large tyres, fancy stainless steel checkerplate and dual batteries are hovering close to GVM unladen. That’s why I got no winch, no bash plates, no rock sliders, no extra spare, no rear bar, alloy rims and aluminium drawers with light ply wood panels. I’m touring not hard core offroading or attending fashion shows and need to save weight for camping gear and fuel and water. The hilux and prado engines have some differences that I know of. Different turbos, different cooling system, different sump design, differences in fuel delivery system. If you want similar performance to prado you could whack a chip in.
Hiya outbjk planning my trip around oz have 2010 sr5 auto, tyres are tsr kelly and i dare say fuel consumption will alter with the chunky tread , so reading your article might try and drive slower.wondering if lockers are really needed .i already have lift kit , winch snorkel and hopefully the kelly tyres do are good job as not tried them yet, had cooper st maxx but wore em out around town for work ,stupid me should have changed for cheap ht tyres .bought hilux after having cruisers as drove one in remote thailand and loved it .they are made there too around the corner from my thai wifes house , some much for supporting holdens around the corner here in adelaide ,i do not understand why aus car manufacturers did not develop 4wd for our market and terrain , enjoy 4wd catchya steve
Hi Steve you don’t need a diff locker. You’ll get most places without it. But with a diff locker you can go slower, smoother, gentler. Less stuff breaks. Plus less damage to the track. And occasionally it will get you out of trouble. I reckon diff locker is a pretty good mod for a vehicle used regularly on uneven terrain. But it aint cheap so need to make a judgement.
Good read! Just curious if you use cruise control on your highway stints?
Hey Nick nah man I don’t have cruise control. The manual transmission hilux never had it. I thought about getting after market but realized I don’t really give a crap. No cruise control doesn’t bother me. Not sure if it would affect my fuel efficiency since I drive pretty slow and try to drive as smooth as I can.
Great info on your site, thanks, esp re Hilux (Peas be upon them…)
Do you cruise in 5th/overdrive? My neighbour repairs transmissions for a living and swears against all use of overdrive – unless deliberately to line his pockets. What says an engineer?
Hey Michael yeah I cruise in 5th. I’ve never had a problem but I never tow. Under high loads it may be better for the box to drop back a gear.
I run a 2000 diesel hilux, I was wondering if you could clear up a question for me.
I am wanting to know if it is more economic to use engine braking or coasting and using brakes.
Some people tell me the engine will be using more in idle than it would under revs using engine braking.
Can you enlighten me please?
Hey Tim when the engine is idling whilst coasting fuel is consumed to keep it idling. When engine braking in gear fuel is no longer injected since the engine will keep turning anyway. However this doesn’t come for free – instead of burning fuel to keep the engine turning you are using up kinetic energy of the vehicle to keep it turning. You had to burn fuel to get that kinetic energy in the first place and will need to burn more fuel to replace it when you accelerate again.
If you need to slow down then keep it in gear. This minimises fuel use compared to coasting at idle since no fuel is consumed and you need to slow down anyway. It also saves your brakes.
If you want to conserve your speed then coasting at idle is better. Idling the engine at minimum rpm uses less energy than revving it at higher rpm in gear. If you leave it in gear the car will slow down more and you will need to burn more fuel to accelerate it compared to the fuel burnt idling and conserving speed. Note doing this might be illegal.
Very interesting article. I recently did a trip over 1200km, most of it was highway speed averaging between 105-110km/h (GPS) and I averaged under 9L/100km. I was expecting around 13L/100km going by the table in the article. My vehicle is a 2008 SR D4D. Maybe the tiny 205r16 wheels help reduce rolling resistance, hence, fuel consumption. Have done around 20,000km so far, various driving, and worst I got was 9.9L/100km. Average is 9.4-9.5L mark.
Hey Matt the table in the article is more for relative comparisons to changes in speed. The actual value won’t be a good predictor coz I got bigger tyres and roof top tent and whole lot of other crap. Plus the trip computer isn’t very accurate. Under 9 is good for 110, nice.
Read this articla a few days ago and ask myself if there is something wrong with my 2005 SR Hilux 1KD manual as could not get anything less than 12L/100km, no matter city driving or outside town. Have 245/75/16 tyres, alloy bullbar and canopy. been driving this for 2 years now and think I am a very fuel conservative driver, light on the pedal, gentle increase and decrease of speed, Adelaide traffic is light…. done injectors recently as one was a blow by… now as reading every once in a while about car stuff I am led to believe that may need to replace/upgrade SCV, as some suggest might cause increased fuel usage. Wondering what your comments might be.
Thanks and cheers
Hi Ruslan from what I’ve heard the scv wouldn’t impact fuel consumption much, it more causes rough idle, hesitation, poor performance. I spose it’s possible to impact fuel consumption. You can check the scv by comparing target rail pressure vs actual rail pressure. If the difference is more than a few hundred psi at steady state then there may be a problem. First try cleaning it. Instructions to clean can be found at newhilux.net forum.
Clean your intake mass flow meter too. That can cause over fuelling. Check brakes aren’t dragging, wheel bearings are good, tyre pressure good.