Mud-club
Vehicle & Technical => Discovery => Topic started by: Disco-Ron on December 31, 2008, 23:36:13
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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.......
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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
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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....
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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
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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....
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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I put £38.00 on friday and i managed to get 103 miles for that :'( . I am thinking a 300 tdi will do the trick. oh well i still love driving it.
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I have to say Iv got an 1992 disco 200tdi and I recone we gettin 30+ at a steady 55-60mph
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on a run tothe lakes from birmngham (around 163 miles there and 163 back, plus two days greenlaning, we used around 22 gallons of fuel. in a lifted disco with larger tyres and the usual EGR tweaks etc.
so thats around 18-20 miles to the gallon, including 75 miles of laning at low speed in low box etc.
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on a run tothe lakes from birmngham (around 163 miles there and 163 back, plus two days greenlaning, we used around 22 gallons of fuel. in a lifted disco with larger tyres and the usual EGR tweaks etc.
so thats around 18-20 miles to the gallon, including 75 miles of laning at low speed in low box etc.
So, in other words, what i'm getting is about right then.......... a; i need to do, is work out how to adjust it so it doesn't smoke quite so much on boost, well, it smokes until the revs have caught up with the throttle position if you see what i mean......
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So, in other words, what i'm getting is about right then..........
yep! :lol:
not great is it. but im looking at other ways of getting it to breath easier, use the available power better rather than just wasting it. will let you know how i get on.
obviously when you dont need all that off road kit in the back, take it out, you WILL be surprised how much of a difference it makes to the fuel economy! it added between 3-5 MPG on the range rover diesel i used to have.
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My last tank full we got 369 miles 300tdi I think I need to put my foot down a bit more. All the best
my tank this time 401 and the light has just come on
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you are quite right squaddie fo, our is not modded appart from collway mudterains