Thread: Fuel Economy 97 S1 Discovery 3.9l

Hi to all,

I just would like to say hello to everyone and what a terrific forum this is. I have been reading it for quite sometime and when we had to rebuild our 3.9l motor due to a loose bore sleeve, this forum gave me a good understanding of how and why things happen so thanks to you all for that.

My question to the forum is now that our motor has been rebuilt we are planning a trip up north towing a caravan that weighs approx 1.7kgs, I would like to know what would be a fair expectation on fuel economy liters per 100k.

We also have a 50l LPG tank, I realise that LPG on long distance does not give much of a saving but around town it is fantastic. The car has the stock standard 80lt Petrol tank.

I have the 3.5l 91 5 speed model and towed two caravans around australia, Furthermore I did a naughty and put on A/T 10.5r slightly oversized tyres.

Best economy ever is North Brisbane to southern side of Coffs Harbour @ 440Ks one driver normal speed early morning. No van of course =86l gas.

Worst ever at tennant creek (I think they pumped the gas with their air hose) which with a van and headwind was 35l/100

Most of the time with caravan on western roads at a steady 95klms/hr and hiding behind trucks (because as they slowed down as did I on the hills!!!) the best I ever got was 23.5l/100 and av 25/100 towing a 1.6T (loaded outback swan)

Remember this is manual, slightly more gutless with oversize tyres small motor. I imagine the auto can max out depending on the loud pedal use and as for the 3.9 I would have thought may have equaled the above. My gas is the old type and with no oxy sensor adjustments on the fly. Gas is fab on highway, and I did notice a 30k range better with the swan compared to the old viscount which had a flat vertical front. Swan was 400kg heaver but higher off the ground which I was amazed at the difference.