Vehicle & Technical > Discovery
Just filled up with fuel...ARGH!!!!!!!!!!!!
Disco-Ron:
Well, finally i got around to filling the tank, and using it, then filling it again to work out a rough mpg figure.....
Didn't expect it to be less than 19...!!!! this on a big wheeled lifted big intercooled 300...... manual!!!
I think i may need to wind the pump down slightly don't you...!!!
I do drive it, i don't believe in pottering about, but 19 is daft.......
Range Rover Blues:
That's half the problem. With big wheels you'll be about 10% out on the oddometer, even though LR speedos read fast the oddo is accurate, so now you have to add 1.9 MPG onto that figure, and that's just for 235/85s.
Next is the added mass of those tyres, we call is second moment of area, or rotary inertia to keep it simple. All your fuel goes into revolving a big mass (well 4 of them to be precise) plus all the transmission etc before you even think about moving 2 tonnes of truck along the road.
then add the gearing is now out, so you have to work hard to accelerate and perhaps your crusing gearing is a bit out (though TBH a standard truck could use another gear at times) but in blue I struggle to hold 5th at a crusing speed and it's even worse when towing.
Now if you find you're making lots of smoke, well that's just wasted fuel. OUrs is the same and I plan to just tighten the star wheel one turn, I only need full fuel at high boost when I want it to go so I'll see how it goes.
Also try fitting a boost guage, you can use it as an econometer, it's surprising but just by keeping uour boot out of the carpet you can reduce over fueling in situations that don't call for it and increase your cruising economy, on the motorway try keeping below half a bar of boost.
Clean the intercooler and inlet thoroughly, fit a K&N filter. I cleaned out the turbo with loads of WD40 and a toothbrush, I also re-roted the breather to keep the inlet clean.
Fit an electric fan, a straight through exhaust etc
Don't use M/Ts when you don't need them, they sap loads of power.
Empty your boot
Disco-Ron:
Having read your reply, i have realised that 19 is without taking into account the lack of odometer accuracy with regard to the size of the tyres.... so maybe that 19 should be more like 21....
I only drive locally, never on a motorway.....
the intercooler is only 6 months and about 1500 miles old..... also has a sports filter, can't remember which one....
it already has just a very small box box fitted in the centre of the exhaust, sounds quite fruity too..!!
The thing is, that this is really only a toy, it's kind of my third vehicle, which for one guy is maybe excessive aswell..LOL!!
I didn't expect it would use more fuel than my 320bhp Impreza though...LOL!!!
Think i'll try to wind the fuel down slightly, and see how it goes......
as for the gearing, i find myself driving round the A roads in 4th, as to be honest, it won;t pull fifth at less than a constant 60 or so..... unless you bury the pedal, which must be worse than staying in 4th, and letting it work a little less hard....
Ho hum....
inchman:
thanks for that info, i 've recently got a 1997 dicso 3.9 on gas. im getting 70 miles for a tenner on gas..but ive standard road tyres and alloys but a set of amazons on steels for mucking about.
cheers Gary
Range Rover Blues:
--- Quote from: Disco-Ron on January 01, 2009, 00:16:19 ---
as for the gearing, i find myself driving round the A roads in 4th, as to be honest, it won;t pull fifth at less than a constant 60 or so..... unless you bury the pedal, which must be worse than staying in 4th, and letting it work a little less hard....
--- End quote ---
Oh yes of course, that's another thing, the engine/transmission are disigned to have the engine at it's miost economical speed for cruising, so big tyres also upset that balance too.
Like we always say though, design is a compramise :?
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