Thread: fuel usage

HI, only got a 3.9 but 2" spring and 2" body lift, if I'm careful on the highway can get 425 before the fuel light comes on, standard tank, 4 speed auto so thats only if I get into overdrive, and stay there!

With a heavy foot you should be able to use as much as you want, no limits!

hope that helps at all

I get around 650km to the fuel light in my 85. Usually takes 65L to fill but getting the tank full involves finding a left leaning forecourt or a lot of rocking.

Isuzu 4BD1T and Isuzu 5 speed. Stock height (maybe +1 inch), 29" tyres.

I don't think I've ever burnt a whole tank of fuel in urban running. It did drop to 8.5km/h when moving house with a tandem trailer and dropped to 6.5 km/l towing another rangie on a trailer.

but I get 310km max on the highway,

If you are getting 21L per 100Km on the highway ( which is the official way to work out economy) then there is something wrong with the tuning of the engine. Its hard to suggest what considering you are running a 14CUX with a 4.6 which needs a Tornado chip. They usually run very lean.

Even with large tyres and a 5 inch total lift and proibably mud tyres!

I get about 14.5-15 towing a 600Kg trailer at 100Kmh on flat ground and 17 in hilly country towing the trailer. 2 inch lift , 30 inch tyres, Thor, 3.9 unichip, O2 sensors.
BTW what is is aim of the thread? Do you want to know if yours is good bad or indifferent. I would suggest few would have your setup so any comparisons would not be all that helpful. BUT IMHO your economy is poor and maybe you should look at a dyno tune and maybe to fit a unichip or other piggyback to give control of part throttle advance and usually a second advance curve for gas). Do this before fitting gas or you may be disappointed with the setup unless you know it is running right at the start.
regards Philip A

I was getting between 17 and 19 litres per hundred, sometimes dipped to 16, and the odd 20.

Best I think was 14.08 l/100km (20 mpg or approx 7.1 km/litre)

I've given up recording, as its too depressing... but then again, I'm used to a Paj diesel and 100% LPG Mazda.

I'm assured that Holden Jackeroos are just as thirsty as RR's... Small comfort!

Philip, - "chip" - what chip ? where? how much ? - and does it make a real differance to a standard engine with the OEM LUCAS ignition module ?

James in Perth,

1995 Classic Vogue SE. 3.9 litre stock standard, and runs smoothly/well.

Philip, - "chip" - what chip ? where? how much ? - and does it make a real differance to a standard engine with the OEM LUCAS ignition module ?

James in Perth,

There are several Piggyback chip makers including unichip( which is fading out as they charge their dealers high fees) and Haltech which seem to be the go now. These chips intercept the sensor signals to the ECU and alter the fuelling . More importantly for a 14CUX, they replace the vacuum advance with a computer generated "vacuum advance "curve. this revolutionises part throttle performance , and full throttle as the V8 can take much more advance than that allowed by The old dizzy.

On a RRC they usually cost about $1400-1500 which includes usually a new module and dyno tuning. Look in the phone book for dyno tuning specilists or see a LR specialist in Perth.

Another alternative, If you are very computer literate google "Megasquirt" but I do not think it is for the faint hearted or have a look at this site
Trigger-Wheels
Regards Philip A

Hopefully here is a scan of the dyno runs of different stages of my car. you will see gains of about 20% with the first stage which was only the chip.
Attachment 40308

Regards Philip A

3.5 carby with 5 speed manual and 31" tyres I get about 380 km out of a tank, but it is just my weekend toy so I don't care

hey phillip, are the O2 sensors an upgrade with the unichip or separate?????