Acceleration ...

This is pretty hard to explain but getting the car moving from stationary is driving me crazy.

If you let the clutch up slow enough the car will start moving pretty much anywhere with no application of throttle at all, if you try involving the throttle whilst releasing the clutch it really doesn't like it and can stall out unless you really slip the clutch - not a habit I am prepared to develop.

It gets even more fun on hills where hill starts are required the bite point is very hard to feel, especially with a heavy trailer on the back.

Once you are moving there is a part of the range where acceleration is garbage. Just doesn't feel right, feels more like a Scania than a Landrover - actually Scania feels better. Once out of the 'dead zone' below 1100 rpm it pulls like a train.

The car is already mapped, has no CAT, no EGR, is running a VGT turbo and large intercooler all sensors are OK no engine fault codes present. Don't know what else I can do. Who in the hell would develop an engine for a 4x4 capable of towing 3.5 tons that had no torque whatsoever below 1500rpm.

I have a 2008 2.0TDi Passat that even in standard form eats the Discovery for breakfast on both torque and BHP across the entire rev range - if only it was plated to tow 3.5 tons !!.

Would anyone here think that the take up I am experiencing from stationary is normal or do I need to keep digging ??

Not normal at all, mine pulls very well, then very strongly from 1800+ when the turbo kicks in. I can tow anything I've had to yet on just a whiff of throttle or tickover in 1st and setting off has never been an issue except when the clutch was slipping!!

Well I don't have the lag issue once I get the clutch fully engaged it will pull like a train from 1100 rpm upwards, I specifically had it mapped for torque, manifold pressure is approx 90kpa (13psi) at tickover which increases to around 145kpa (20psi) from 1200 rpm upwards and pretty much stays there unless pulling hard where it will increase to around 165kpa (24psi so pulling power isn't a problem. Exhaust temperature has yet to exceed 500 Deg C at tickover it is between 80 and 100 deg C. Car is returning between 30 and 32 to the gallon and I have yet to see any black smoke I have no idea what the numbers are for torque etc.

It is getting the clutch engaged that is the fun part. Just feels wrong but it is very hard to explain - perhaps I am being too cautious with the clutch the thought of changing one has my wallet and will power running for cover since I will never do that particular job myself again - gearbox etc is just too damned heavy to mess with on your back on a driveway - just not sure what is normal on the Disco TD5.

Right. Hard to say then, I haven't thought about a bite point, 'cos I just do it!

Maybe you could just try doing a normal start, when towing, and just let the clutch up and add throttle as you do it, just try not to dawdle or slip the clutch. There's always an amount of clutch slippage anyway, but if you do it smoothly it'll be no more than usual.

let the clutch up and add throttle as you do it

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That's part of the issue, if I do try to add throttle at the same time it seems to 'choke' on it unless the rpm are pretty high perhaps it's normal and the clutch can handle hit without getting cooked. Getting stuck on a hill with the trailer on the back though is a real stress fest ...

You say that it's been mapped...wonder if that's the issue.

In normal factory condition, there is a bit of a flat spot as you let out the clutch and you often have to give it a bit more throttle to get the plot moving, but that's really something that you soon learn to accomodate with your driving style. Often that's a reason some have the mapping done. What you describe seems a bit more though.

I wonder too but as you kind of hinted at I had it mapped to get around the issue, the mapping helped elsewhere but not with this particular issue.

I actually had a bust up over on another forum because some jackass reckoned that the TD5 is perfectly OK, didn't need mapping or de catting etc etc and it was me at fault.

I had it remapped because the alternative was get rid, the power delivery when I got the car was terrible, more suited to motorway cruising than towing.

I've had both TDi's and TD5's and from my experience in general you need to give the TD5/manual 'box combo more revs than a TDi.

With a TDi you just lift the clutch and you can pull away. With the TD5 if you want to pull away smartly or if you are towing something or at the start of a hill, they need a little clutch slip - just for a second or two - to get them rolling.

You won't harm the clutch unless you give it great handfuls of revs and obviously I'm not suggesting that.

Try a 3.5 ton box on a hill with a TD5 I had no towing issues with the P38 but that was 4.6 litres and auto, my last 4x4 had zero issues but it was a 3.4 litre petrol and did around 7 to the gallon when towing, it decided to lunch it's gearbox and a 16 year old car at £2500 to repair ... well here I am.

Trying to get a feel for what is normal in case I'm chasing an unreachable goal ...

Your manifold pressure is too low - it should peak at 230.

I've seen a similar problem on one that I put my nanocom on and it turned out to be a blocked cat. This wouldn't let the exhaust out so the turbo wasn't spinning up enough. Replaced with a non-cat pipe and apparently the difference was amazing.

But having said that I wouldn't expect anything below 1200 rpm - but maybe that's just me.

230 kpa - ???? that's 33 psi ... are we talking boost or manifold absolute here. I thought the ECU for these engines choked at around 102kpa manifold absolute (1 bar or 14.7 psi) that's why the boost box is on there.

Absolute (ie boost is around 130). If you plug in nanocom or similar you should see around 100 with no boost rising to 230 (at which point the wastegate should open to spill the excess).

IIRC the limit is 210 for Defender TD5s.

That's pretty much where it is - 90kpa on tickover rising pretty sharply to 145 by 1200 rpm with peaks to 180kpa if I hit the loud pedal but all this is on the driveway. The system was / is configured to run 24 psi max boost.

I don't have a wastegate - VGT turbo's don't have them.

Be in no doubt once moving the car is an animal, a flying machine, the difference now to when I got my hands on it are massive, the VGT turbo and intercooler changed the cars character entirely and is a modification well worth every £ it costs.

our td5 tows a two horse trailer no problem......power is 1800 - 3000 but once used to it, no problem. Yes pulling away needs a few revs on board but the total train weight is 5 tons plus so only to be expected.......

It is what you're used to I guess and partly the reason for the concern / questions. The power is still in the wrong place for towing though (my opinion of course), torque low down to get and keep weight moving would have been my preference over a motorway cruiser.

our td5 tows a two horse trailer no problem

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As does mine but on hills that clutch isn't going to last long with 3 tons plus on the back, I've already had one occasion where starting in low box was mandatory because I simply wasn't going to have a clutch left.