That would be great if you could. Ive had the induction pipework off and the lower boost hose but not the metal pipe or short boost hose that connects to the turbo itself.

The smoke test done by the 2nd specialist should have shown any leaks up though... in theory.

Ill see if i can catch this sound on video

As I thought, no air type noise. Just the grunt of a V8 at full chat.
So, as you no doubt suspect, find the cause of the noise and you'll probably sort the issue. The short hoses do give up though not common. 2007 Vogue TDV8 in Zermatt Silver with Charcoal

Thanks for checking Grofus.

Ill try and get a video shortly so you can hear what I am hearing.

If it is a boost leak ill be amazed as to why it didn't show up on specialists smoke test or the live data for that matter.

Just wanted to say thanks again everyone for your help and for putting up with me!

No bother. We wanted sorted as much as you do.
Well, nearly.  2007 Vogue TDV8 in Zermatt Silver with Charcoal

Thanks Grofus.

Just been out and tried my best to record this sound but no dice.

The rushing air almost sounds like the heater speeding up (its off during my testing) so that could be nothing but there is a definite sssh sound when i accelerate to 2.5k ish and lift off throttle. Suppose this could just be the boost being dropped though

I know how you feel , i have an old Izuzu npr, it started chucking out white smike over 2k revs , four montths later , 3 visits to Izuzu , 4 visits to indies , changed 1.5k euro worth of parts , no fault codes. 4 months later , back to normal out of the blue !!!! I feel your pain sir. 2015 4.4 AB
GSXR 1000 K5
R1 1998

I have been waiting 6 months for this thing to fix itself Dolph!

Been out driving again (no wonder fuel doesn't last!) and out of desperation tried the old removing the n/s intercooler hose trick again. I only removed it at the intercooler end, counted to 20 and then refitted.

Sure enough so long as I drive carefully the damn thing drives nice. No lag pulling away and has that effortless cruising ability back. (only drove up to 30 mph as I didn't want to upset the thing)

Please believe me when I say I am not making this up!!

I'm following this thread closely, it is very odd indeed (and I don't like an unsolved mystery!)

Not sure I have much to offer in terms of suggestions but if it helps I've got a bit of time to take mine out tomorrow and I'll see if I can record some video/audio for you around 2-2.5k rpm - it's a 3.6TDV8 same as yours.

Mine make a bit of a noise on just after startup for the first 50 metres or so, sounds like a lot of air being sucked in by a fan or something like that, then it quietens down and sounds normal enough. I'll try to capture it it if I can.

I'd go out now if I could, but unfortunately I've had a couple of whiskies. Well, not unfortunate for me, but, you know... 09 RR Westminster 3.6TDV8 - Stornoway Grey / Black interior - now gone (sad face)
Nissan X Trail 1.6TDCi Tekna
Fiat 500 1.2

Thanks Tugger, I think the sound you describe at initial startup is the viscous fan running which is normal. It quietens down by the time im turning onto the main road.

The 'sssh' sound im hearing letting off throttle at 2.5k rpm could be something or nothing. Can't say ive noticed it before until today.

Let me know if you get this same sound as I know Grofus doesn't on his.

The smoke test might not show a leak which needs heat and high pressure to reveal itself.

I’m thinking if the boost leak is after the turbo, this may explain the MAF difference, but the MAPs may not pick up a large difference and throw a code.

When my air cooler outlet hose split, I didn’t get any codes but my son could hear the hissing under load.

So, where am I going with this.......

Refitting your new hose maybe seemed to cure the issue (at the time) as when you went for a drive again the leak didn’t manifest itself as the engine was cool etc etc. a red herring as Grufus said.

I’m not sure if I’m making sense......

Remind us if you changed the short elbows at the back of the engine. Or check to see if the plastic is cracked around where the jubilee clips sit.

Maybe try spraying soapy water with someone revving the engine hard 2007 3.6 TDV8

Perhaps its time to revisit the port deactivation components and wiring.

Were both thinking along the same lines cheezels.

Although ive had the smoke test done I don't think this would be under much pressure? (Ill have to enquire)

The charge pipework is at around 15 psi just at idle.

Ive found out previously that any eager acceleration after conducting my miracle hose removal fix reverts me back to square one.

And I agree with you on the MAF thing, a boost leak would allow air to exit the charge pipework quicker allowing more air to pass through the MAF giving me my higher reading.

Ive had all 4 short hoses off, all in good condition and no visible damage to the plastic inlet manifold components.

As for the port deactivation Graeme, I have previously tested the solenoids which click when 12v is applied so should be ok. I also pulled 20 inches of vaccum on the actuators and I can hear the flaps moving about inside the manifolds (engine off of course)

A boost leak would cause black smoke

Visited a friend today with a compressor and we made up a boost pressure tester out of some pvc caps and an airline fitting.

Tested the system up to 20 psi and absolutely no leaks to speak of.

So no leaks with the smoke test and none with a pressure test.

I feel we have been over it all and I have done all I can do short of removing the remap or replacing the n/s turbocharger.

Now on the lookout for a replacement vehicle.

Might be different when the hoses are hot.
Mine runs lovely when stone cold but as soon as she’s up to temperature I get boost loss. The engine runs rich and I get a diesel rattle and it faults. I’ve wrapped a load of aluminium tape around the suspected faulty hose and it runs better with improved acceleration so I’ll be replacing both top hoses for silicone ones this week. I’ve had both off and can’t see any cracks or holes apart from cracks you get in a worn tyre, so I can only assume it’s gone porous and gets worse when the hoses get hot. Mines been remapped as well so it’s probably amplified. 2010 MY Vogue SE TDV8 3.6 Stornoway Grey- fully loaded