Just finished a return trip from Bundy to Mackay. I figure its about 640klms each way. On the way there, using normal unleaded I got 640klms out of a 95 Ltr main tank. I actually ran it dry. By my calculations that's 14.5 ltrs per 100klms. The engine has 160'ks on it, 285/75 tyres, extractors, and about 10deg of timing advance. I run the tyres with about 45-50psi.

The fuel light came on at about 530klm and ran dry at 640klms.

I was pretty happy with that economy and was looking forward to getting the same on the way home but I used the ethanol blend to fill up. The fuel light came on at 450klm and I topped up from the sub about 550klm.

It might have been air con , air temp, or any number of other variables but it will take a bit of convincing before I use ethanol blend again.

Around town I drive pretty steady and get about19-20 ltrs per 100klms. I would be interested to know what other petrols get.

Me thinks the first figures must have been in error, maybe put some fuel in and not included it in calculations? The second set of figures sound normal (275 tyres at about 38psi). 20lt/100 km is about what I get round town (E10) and it might go down to 16 - 17lt per 100km on open road if I don't push it.
As I said 275 tyres 38psi, no roof rack.
Mike

Yet to to the timing mod, but that Ethanol is crap in my 80! It uses heaps more fuel than on standard unleaded, premium gets me the most klm's by far...


Cheers, Scott

dam thats good fuel economy, i usually get around 400ks from a full tank, i use lpg during the week and i have 2half inch exhaust no extractors. Do you think your tyre pressure is right i have 285/75 mickeys and run around 40psi..

I have an auto 4.5, and have fitted 265/75R16 BFG A/T at 40psi. On a recent trip of about 3000km all on road, fuel economy ranged from 16.5 litres/hundred to 17.5 litres/hundred. The 80 was not really loaded up, had 5 people, and probably 100kg of luggage max. Cruising speed for me is about 100-110km/hr from the gps. I have zero speedo error at 100km/hr. If I drive at 90km/hr with the tires at around 40-45psi, and go easy on the throttle, then I have managed to get 15 litres/hundred km. All these figures were acheived on 91 octane (E10). Around towm the consumption rises to about 19.5litres per hundred. I go easy on the throttle, and try to coast to the lights. Mine has just over 190k km's on the clock. It will be good to see what other guys are getting. What I am trying to get my head around is why the tyre size seems to have such a huge impact on fuel consumption (at least all of the guys with diesels are saying that there fuel consumption went up when they fitted bigger diameter tyres).
Cheers
Adam

My FZJ80, 1FZE from 1998, with 255x85x16 always needs 25liters/100km.

15- 17 liters is a dream for me...

All figures and fuel usage on trip there was accurate. No intermediate fill-ups, just a straight through trip. Return figures arent as precise as when I saw how bad I was going I gave up and refilled from the sub-tank rather than running it dry.

To recount the trip from Bundy to Mackay, I filled main and sub on the morning of the trip in Bundy, reset odometer at servo, drove until engine konked out, calculated 95 litres of fuel over 640klm and got 14.84 ltrs per 100klm. I drove about 20 klms up the road and filled up sub and main and put in 98 ltrs which still equals about 15ltrs per 100klm.

That is extraordinary fuel consumption you guys seem to be getting there. There must be something very wrong with mine as i am lucky to get 400 km to the main tank going from Brisbane to Bundy. That is with stuff all wieght as well .I am running 11/92, 1FZ-FE, auto, alloy roof rack, 2"lift , 265/75 16,alloy bullbar,narva spots,uhf. I have owned the car for about 8 years and never had econemy like you out of her are you sure those figures are correct and you're speedo is right. Oh and i always use unleaded never E10 crap or that hi octane stuff " im not made of money ". Buy my sums i must be doing about 30ltrs per 100klms and even more around town getting about 200-250klms to a main tank.My tyre pressure is running 35psi as i was told by the tyre fitter any more and you wear the middle as the pressure increases on highway trips {apparently}. I would love to get that sort of mileage out of mine but i think that is a dream.I know that the auto's use more than the manual version as my mechanic has a 93 manual and we have looked over mine several times to see why mine will use alot more fuel than his does and have come up empty handed. It will be interesting to see what other people are running and what there mileage is as mine seems to be S#*t compaired to some others.

There must be an explanation. Even on the E10 stuffi got 520klms out of the main tank before I switched to sub.

My tyres say they have a maximum psi of 60. I figure 45 psi is well within the limits. I will no doubt wear the outer edges of my tyres before the middle.

Mine only ever got around the 350-380 klms per tank (till fuel light came on) then when the 33 ATZ's went on, it dropped to 300 - 340! You sure you have a standard tank in there???


Cheers, Scott

Woah these figures are all over the shop, Are you guys with the larger tyres accounting for the difference in diameter when calculating consumption figures

I am yet to acurately test mine as i am not 100% sure how far out my odo is but i only had to put in 64 litres at geraldton after a driving up from perth's northern suburbs, so roughly 400-420kms i had filled up the night before so i had already travelled a good 30-40km before starting the trip, based on this i was getting around 15L/100Km on the highway, not bad for a fully loaded cruiser on 315's (35's), however these figures drop considerably around town/offroad

Cheers
Dan

couple of other things to think about:
use GPS to measure distance
every time you start the engine a small amount of fuel is pumped over from the sub tank to the main tank
manual or auto transmission
yes tyre pressures will make a difference
engine clutch fan, as the kays rack up it gets less efficient and slips more so draws less from the engine.
oils - thicker oils cause more drag
full time 4WD V's part time 4WD
roof rack causes drag, maybe 1-2 extra ltrs per 100 used

I've been thinking about the effect of tyre size on fuel economy, and the only thing that comes to mind is speedo error with the larger diameter tyres (as already mentioned by a couple of you guys). When you increase the tyre size (diameter) for every revolution of the wheel you are actually going further than the odometer registers. So you think you have travelled 200km, when you have really travelled further, say 220km, thats 10% speedo error, and possibly 10% more fuel consumption than you have in reality. The larger diameter the tyre the lower the rolling resitance (for the same tread pattern). You will have slightly worse aerodynamics with a larger diameter tyre as the car sits higher from the ground.
cheers
Adam

We are currently heading north to the cape and my mates 1fz 105 is doing 20-21 / 100. that runs 36x15.5's, 4.8 diff gears, 4" lift, a rooftop tent and FULLY loaded. I thought that was pretty good.

How much do you guys pay for 1L fuel? In Belgium it costs 1.645 EUR => 2.23 Dollar