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Bigj66

TD5 fuel economy

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Now that I’ve been driving the 110 for a few months I have noted that it seems to sup juice quicker than I thought it might. It does have the ECU mapped along with the boost adjustment, straight through exhaust and large intercooler but it certainly doesn’t get flogged by any means. Is this normal for an upgraded engine? I haven’t done a proper consumption test yet so this is just an impression but what sort of range could I expect from a full tank with mixed driving? Just interested to learn what others are getting for when I compare with mine.

The engine also revs excessively at motorway speeds and in traffic first gear is all but useless apart from starting off on steep hills. Has anyone tried the high ratio gear set from Ashcrofts in their transfer box and can advise on whether it’s worthwhile or not? I spend a lot of time on the motorway crisscrossing the Pennines so anything that can reduce the engine noise a bit and improve fuel economy would be great. The straight through exhaust also tends to drone at speed so I’m thinking of replacing it with the original silence that I have from when the conversion was done by the PO. Am I likely to notice much of a drop in power by reverting back to standard?

Finally, what would the symptoms be if this fancy flywheel the TD5 has was to develop a fault? When cruising it sometimes feels as if there is a vibration from the engine as if an exhaust pipe was just touching the chassis. When I’m driving at slower speeds about town you can’t notice it as much. One other thing I’ve noticed is that the clutch action is like flicking a switch, it’s either on or off with little feed in between to smooth out the engagement. Is that just a feature of the TD5? Was I spoilt by the V8 and BW box in the Rangy? 😭

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Best place to start would be measure what mpg you're actually getting. I doubt any of those mods are making it worse; the tuners usually claim to get better mpg! They're not renown for being particularly light on fuel, though. Low to mid thirties maybe? But.... Since you mention revs and transfer ratios: the Lt230 comes in 1.003, 1.2, 1.4 and 1.66:1 ratios. Best bet is get underneath and find what's actually fitted, the serial number will be stamped on the back of the case. Standard defender will be 1.4, but some people like to swap for the discovery 1.2 ratio for better cruising. I have a mate who's running a 1.66 ratio box and struggles to go over sixty in his 300tdi 110 without the world ending. Sounds like you'd benefit from a 1.2 transfer box. I used an Ashcroft kit to convert my 1.4 box to 1.003 (they're not common to find) as I'm running the original 4.7 diffs in my 109. If you really want to rebuild the transfer box it's an option, but I'd just pick up a good disco unit (though make sure it's one with the diff lock), pop some new seals in and enjoy if I were you. 

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Might be worth having a look at your clutch pedal to see if it is fitted with the spring assist which Land Rover fitted to the Tdi but seem to have deleted in later years. For such a simple modification it transforms the clutch pedal feel.

As well as the various transfer box options there is also the option of a taller 5th gear ratio.

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I have a 110 TD5 double cab and one of the best things I have done is fitting the 1.22 transfer box. Despite the increase in the gearing, it still pulls well in 5th even with our Ifor Williams trailer on the back. I did notice he fuel economy improved but cannot quantify this. My neighbour did comment on the fact I had cobwebs growing over my fuel cap!! 

As for the vibration, I also have this and appears to be a TD5 issue. Changing my clutch and flywheel made no difference!

Toby

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I have a TD5 110 SW and do around 12,000 miles a year in it.

MPG l get 26-28 in mixed mainly town driving. That’s just normal use, not excessively fast or slow.

Mine is remapped with EGR delete but nothing else.

l have the rev  counter.

On the motorway the best cruising speed is 65mph, at that speed it’s doing about 2700rpm. At 70mph it’s at close to 3,000 rpm which is still OK but l find it better to sit at 65.

l find first gear to be fine, and always use it when starting. If yours seems very low l wonder if your gearing has been modified, not sure you can lower the overall gearing though?

The clutch should be progressive, mine certainly isn’t on/off you may need a new clutch, but first check the hydraulics.

 

Edited by Lightning

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Thanks chaps, some good feedback there. I have the spring kit just fitted and to be honest, it’s since then that I noticed how much the pedal is pushed back outwards by it which probably doesn’t help with the finer control of it and seems more like I’m dumping the clutch. I do know that I have a small amount of wear in the rear prop splines and have a new one to fit. This won’t help with any vibration but it sounds like it might just be a fact of TD5 ownership. Bring back the BW auto!

I might replace the clutch master and slave cylinders as part of a general overhaul and see if that makes any difference and it sounds like the Ashcroft kit will be a worthwhile investment given the amount of motorway work I will be doing.

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If I swap to a discovery 1.2 box with diff lock is it just a straight swap or are there differences between that and the 110? Is it an easy diy job?

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1 hour ago, Bigj66 said:

If I swap to a discovery 1.2 box with diff lock is it just a straight swap or are there differences between that and the 110? Is it an easy diy job?

Yes and Yes. Some Disco boxes had no difflock facility, but the gubbins is still inside, so just needs the linkages and cover swapping.

Shame you are not nearer to me, I have one you could try to see if you like the effect

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Presumably if I swap the complete box then the low range gears will be increased too or does the Disco just have different high range gears?

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Low range is same in all LT230s.

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Ashcrofts site has a gearing calculator which is useful for finding out where your engine speed is for a given set of ratios/road speed.

Remember larger tyres will have an effect on your gearing too, I have a rebuilt 1.22 to go into my 90td5, I originally built it for my 200tdi but it's fine on its 1.41 (60mph GPS @ 2300rpm, 70 is about 2900 iirc), the 200 doesn't get pushed much. 

Going from my previous td5s, anything about 28mpg is average. The most I think I ever got was about 39....once...never managed to repeat it!

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On the motorway now, mine is doing 2400RPM at an indicated 70MPH - which makes it so much nicer to drive now with a sweet spot at 75 mph (where possible!). Rev counter and speedo matches Nanocom, but speedo could still be out depending on tyres. I am running fairly new 265/75. As I said before it still pulls 5th easily and climbs Haldon Hill outside Exeter in 5th at 70 mph, but does need 4th with the trailer on the back. It is chipped, but no idea by who.

I have a 28D Tbox (RRC) rebuilt by Ashcrofts and it fitted straight on. The High low switch cannot be connected but was not on the original Tbox anyway. You will probably find that it has been changed to stay in low ratio on the ECU by connecting to earth. I tried mine earthed out and then disconnected and it improved the throttle response when left disconnected.

Toby

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I used to run a Td5 110 CSW with a Jeremy Fearn Stage 2 tune (big intercooler, remap, etc) and that returned 26mpg typically (although I didn't always drive it with the lightest of right feet!). It's predecessor, a 300Tdi 110 CSW, generally returned 28mpg but wasn't anywhere near as quick. Both responded well to raised transfer box gearing, pulling comfortably with 1.2:1 LT230 and Borg Warner transfer boxes respectively. These greatly improved motorway cruising without costing too much flexibility for towing ~3 tonnes.

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I can get my hands on a good Disco 2 TD5 TB with diff lock serial number 68D. Is that the correct one including wiring for sensors and switches etc?

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I average between 20 and 23MPG from my stock 90TD5 in day-to-day driving (a mix of free-running A-roads and 80MPH-down-the-outside-lane-with-the-BMWs fun on motorways) - I tend to drive it more like a sports-car than a lorry, and overtake much more than I get overtaken. The TD5 loves to rev!

Hitch the big fully-loaded 3500Kg Bateson to it and on A-roads-with-roundabouts it's more like 17MPG.... but I'm getting paid well for this kind of use so fuel-consumption's not really a worry.




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I have a map and get 30mpg.

I fitted a 1.2 transfer box - but measured next to no difference in mpg, though I much prefer it.

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I brimmed the fuel tank tonight so have reset the trip counter and will see what sort of consumption I’m getting. Anyone can say if that 68D suffix box is the right one? I’m informed it’s out of a 2004 Disco and my 110 is also a 2004 model. Will the 1.2 gearing be okay with an engine that’s kicking out more power than standard (around 165 - 170bhp) or does the gearing need to be slightly higher again to give the same effect as the 1.2 with a standard engine? I’m running on 265s.

Clutchwise I’m now convinced it’s a hydraulic problem as the pedal feels ‘sticky’ when it’s released and not very smooth. Should be an easy fix although I did hear a slight whirring noise when it engaged earlier so I’m also wondering about the release bearing or clutch itself now. Could be a combination of several things to be honest but I’ll go through them one by one to try and eliminate issues as I go.

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I think 1.2 works better with a more powerful engine.

One of the most useful changes for me was in coming out of junctions - with the taller gearing I could clear more road before needing to change up and that felt loads better.

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I am not sure about this but do the Disco 2 Tboxes not need the rear output housing to be changed to allow the speedo to be connected?

Toby

Edited by Landrovernuts
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10 hours ago, Anderzander said:

I think 1.2 works better with a more powerful engine.

One of the most useful changes for me was in coming out of junctions - with the taller gearing I could clear more road before needing to change up and that felt loads better.

That’s exactly what I’m looking for with mine. First gear is of little use in those circumstances. If my 2nd gear becomes 1st with the 1.2 box and 5th is higher again then I’ll be happy.

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A weird feeling clutch can also be the pedal pivot. Worth a bit of oil/grease to rule that our first I would suggest, before delving deeper.

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Before I commit to a purchase I just want to check that the 1.2 ratios will be a better choice than the 1.003?

And that a Disco 2 68D box will swap will mine?

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1.2 is what you want.

Providing that Disco box has the Centre Differential Lock on it - you’ll be fine.

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1.003 will be way too high, 1.2 is the ratio you want.

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On ‎10‎/‎6‎/‎2018 at 7:46 AM, Landrovernuts said:

I am not sure about this but do the Disco 2 Tboxes not need the rear output housing to be changed to allow the speedo to be connected?

Toby

they do,

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