Thread: 3.9 Economy what do you get?

Have a 1995 Disco V8i 3.9 auto, 251,000km on the clock, am getting 18-20L/100km over the last 3.5 months of ownership.

I have done a fair amount of low range work, and lots of short trips around town in that time, and I have a very heavy foot, as I love that V8 sound! No long trips as yet, but the previous owner reckoned on 14L/100km on their daily commute from the southern highlands of NSW to Goulburn via freeway.

The V8 is our second family car/business car, so fuel use isn't an issue [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img]

my v8 used to get 450+ klms to the 70 odd litres around town in heavy traffic with the aircon going after i had the ignition module replaced.

on the highway it got 500klms no load etc

worst i ever got was 205klms out of a tank pulling a trailer thru rugged sandy country.

the tdi i have now gets 700+ klms out of 70 odd litres, but the enonomy comes at a price. they are nowhere near as smooth as a v8 and from a standing start, with the aircon on, wouldnt pull a skin of a 2 day old custard...

once you have them wound up they are not to bad at all but at the lights they are not that flash. the auto does help immensely as the spool up on the turbo seems to really suit the auto.

i definetly smile at the bowser with the tdi as i do 1000+ klms per week on average.

Incisor,

By ignition module do you mean ECU, like replaced with unichip or Motec etc? and how bad was it before?

Glen.

My Father used to have a Series I ES Discovery V8 with an auto, and he did alot of highway stuff, usually getting around 17L/100Km.

That poor economy can be blamed on the factory computer, quite a basic setup it is too.

Chipping, or even a complete after market ECU can take heaps off the usual consumption.

An aftermarket performance camshaft is also a good way to get the engine to work more efficiently at a certain enginne speed. The common Camshaft manufacturers (Crow Cams, Crane Cams, Waggot Cams, JPC, etc) have a variety of cams to suit all the Land Rover V8s. See www.rocketindustries.com.au for info on all the brands of performance gear.

Originally posted by seqfisho
Incisor,

By ignition module do you mean ECU, like replaced with unichip or Motec etc? and how bad was it before?

Glen.

no, not the ecu

the ignition amplifier, my original one seemed to go alright but i had heavy fuel consumption and occassional stalls. had it replaced and wala different vehicle. good economy for what it was and a lot smoother.

I get around 14-16 on the highway and around 24-27 around town.

But mines in a 110 and has carby's

An injected one in a disco would have to do a lot better.

My S1 manual V8 gets 21-23L/100Km city but these are mostly very short trips (<10Km), suburban running would be about 18-20L/100km. Freeway best is 15L/100km. Towing a 1.5tonne van at 100km/hr 20-23L/100km.

Have big exhaust, stage 3 cam, ECU re-mapped to suit, port matching. Done 140K. Goes like a rocket but economy improvement seems an unattainable holy grail for Disco V8s. But the sound...yeeehaaa.

Reluctantly selling it, due to health reasons, have to have an auto so will get a S11 TD5 when I sell the V8.

Silverhammer.

[img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img] 12.3 l/100k (23 mpg) at 110 kph.

5.7 litres. [img]style_emoticons/<#EMO_DIR#>/smile.gif[/img]