Hi all
I have a 4.4 TDV8 2011 L322 with 118k on the clock. Its Overfinch badged but don't think there has been a remap... but there is always that possibility that it could have been tinkered with.

I find that when you accelerate with enough gusto to get high revs, there is a dip in power between 2300 and 2500 revs. It happens every time you accelerate like that and its easy to reproduce... is enough to be noticeable but not enough to be a problem.

I have no concerns with power delivery with the smaller turbo (although I do feel its a bit slow to spool up at times) and the larger turbo is fine also. Its just that crossover between the two.

Ive never seen any smoke from the back of the car, and do an Italian tune up every so often (with a warm engine) to ensure there's no oil buildup in the large turbo.

Does anyone have any suggestions on what the cause is? or what I need to check?

I plan to check the throttle body for EGR gunk regardless due to the age and mileage - could it be gunked up internals? Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

Possibly the MAP sensor needs cleaning but also the ECM may not be at the latest s/w level. My April 12 build wasn't at the latest level which I had upgraded to overcome the known hesitation while on cruise control at around 100 kph but I noticed after the update that the cut-in and cut-out of the (smaller) secondary turbo was considerably smoother.

Cleaning out the plenum and throttle body made mine feel like it had 3 turbos.
I think they have got so much torque and pulling power that you don’t notice a gradual drop as it clogs up with gunge, but the sudden step change back to full power when it is cleaned out is gobsmacking.
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

On my list of jobs to do! It's filthy job by looks of it. I recall a DIY thread sometime ago 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
New Defender D300 90 on order so "Rory" will be going to a new home....!
1974 Series 3 Lightweight = "Millie"
My preferred specialist: www.glenrands.co.uk
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The state my MAP sensor when I took it off to clean I can only imagine what's inside. I think cleaning the throttle body would be fairly simple and in car job with some brake cleaner and a toothbrush but for the plenum itself I'd be tempted to buy a cleaned S/H one rather than try to clean it myself as I just don't have the facilities to deal with that amount of black filth........ 2012 TDV8 Vogue (L322)

I would be very wary of buying a secondhand plenum off eBay or similar.
So many have been changed because of hairline splits along the seam, which would not be evident until fitted.
I think new ones are c£500. ,
An old plastic baby bath and a pair of Marigolds with a couple of bottle brushes and a bottle of Gunk will get most out.
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

This was in mine and more!! Easier to take the throttle body off to clean it.

I'm now itching to do it! I love the smell of Gunk  2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
New Defender D300 90 on order so "Rory" will be going to a new home....!
1974 Series 3 Lightweight = "Millie"
My preferred specialist: www.glenrands.co.uk
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Rob, get some wire coat hangers, flexible metal strips, long handled fine wire brushes, shaped scrapers, bunches off cloth tied to string, more scrapers, decorators shaving hook and anything else you have lying around. Easy. LOL. And disposable gloves or you will have black hands for a week!!

£500 seems cheap compared to dealing with that mess..... 2012 TDV8 Vogue (L322)

Thank you everyone for the replies and suggestions.
That is a lot of gunk and crap out of the plenum in that photo! If mine is that bad then no surprise the turbos are struggling to spool up! Given the comments so far I do feel she needs a good clean… and I’ll clean the sensors while I’m at it.

Apart from the elbow grease with cleaning, is the removing and refitting of the plenum and throttle body much work? Is there more that could do with a clean which you can get to with the engine still in the car?

And when this is all done, plus had the gearbox power flushed, I am looking to flash the gearbox. I’ll also closely look at the other engine related updates at the same time. If the updates help solve these little issues then I’m up for performing the updates! Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

There is a DIY thread on here on how to remove it.
Gearbox flash - personally I wouldn't. Change the oil, yes.
 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
New Defender D300 90 on order so "Rory" will be going to a new home....!
1974 Series 3 Lightweight = "Millie"
My preferred specialist: www.glenrands.co.uk
--------------------------------------------------

Why don't you just take the MAP sensor out the top of the plenum chamber and clean it first. I'll more or less guarantee it is clogged up. If that doesn't improve things make sure the secondary turbo activator is free to move. It opens roughly at the rpm you state.
You can also take the egr pipe out of the side of the plenum. Mine had a couple of the holes blocked in it.
If you do take the plenum off, have some soft pieces of foam ready that you can put in the elbows of the inlet manifolds to stop any crud going down while you clean them.

Kevin,
It would instantly drop into restricted performance if the CSOV was sticking when at 2,500rpm.
Plus is gives a very clear fault code to locate the fault. (sorry I can’t remember the code).
Mike. G reg 2.5VM Vogue Portofino red 1991- 1999
V reg 2.5td P38 Rioja red 1999- 2006
53 reg td6 Vogue Oslo blue 2006- 2015
11 reg 4.4 TdV8 Vogue SE. Baltic blue 2015- date.
https://www.fullfatrr.com/forum/topic56162...tty+affair

Thanks Mike. Didn't realise it gave a code if it gets stuck. I've still got a conversion kit sitting on my garage shelf after you highlighted the problem.