I feel that this engine has a substantial turbo-lag and starts to deliver the goodies only after 2000RPM, peaking at 3000RPM.

In your experience, is the turbo-lag ON THIS PARTICULAR ENGINE minimized by chip-tuning or does it stay the same in the overall performance improvement?

thanks! Cheers,

Andrei

If you think the TDV8 is laggy, you're lucky you don't own a TDV6

Chipping does improve this across both the diesel engines. 

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I haven't noticed any lag worth commenting on with my TDv8............................ but then I did come to it after 2.5 years of TDv6 ownership. 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW

If you think the TDV8 is bad you should try a Scooby Type UK when it is off boost, at 30mph in top you can watch Fiat Pandas out dragging you 30 to 60 in top is counted in minutes not seconds!
PS it will do 0 to 100km/h in 4.2 seconds
I traded that in for the TDV8 and have not regreted it  Sons of dogs come hither and get flesh
Clan Cameron

Don't the Evos have the same trouble? I seem to remember TG doing a very similar thing... putting it up against a Smart car or something I think it was. 

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That was the FQ400 ... huge turbo and lodsa lag, t'was on Dave last week, could keep up with a lambo Gallardo and be out dragged by a smart  Sons of dogs come hither and get flesh
Clan Cameron

Smart outdrags Evo......................... bet Mitsubishi loved that one 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW

it was over a distance of 1.7 miles of the Top Gear runway from 30mph in top gear and the Evo was still 2 car lengths behind ... but catching it up fast... very fast Sons of dogs come hither and get flesh
Clan Cameron

I think the turbo lag experience is caused by the gearbox and not the turbo.
If you rev up while in neutral you should hear the turbo whistle while on small throttle openings and quite low speed.
I've found the problem to be the gearbox ecu (which is very clever) and learns your driving style and adjusts shift points to suit. If you give it a bootful (usually on the approach to a roundabout but always at a critical moment) the ecu takes a full second to decide wheter to drop 1 gear or 2 , changes gear and then feeds the power in steadily so you don't spill your drink. This usually creates a brown trouser moment where you have to make a decision to stop or hope no-one hits you amidships

I convinced myself it wasnt turbo lag by driving around for a few days in semi automatic command shift .
When forced into gear you should find that the throttle response is much better and lag almost none existent.

Chip tuning a TDV8 will improve the response but it wont affect the gearbox response time.

ISTR there has been a software update for the gearbox which alters the shift response and hangs onto gears for longer without hunting around so much.....OR....have I dreamt it?

Good luck

Mart  Jaguar XF 3.0D Portfolio
RRS TDV6 HSE 2006 , Zermatt , Gone

All,
Thanks for your posts. I am sure itis turbolag - I own a turbopetrol Audi, so I am well aware of how the turbo behaves.

I do understand that there are cars with worse turbolags, but I own this one  Cheers,

Andrei

Personally I shift it across to sport mode on approach to a hazard/junction/standstill so that it double declutches quicker and holds the gears longer giving one a swift exit It will also then produce some good engine braking and surprise anyone who is tail gating
Certainly no turbo lag. TDV6 - gone
TDV8 - gone
Audi Q5 3.0 Tdi Sline wef 6/11/10

Josh wrote:

Personally I shift it across to sport mode on approach to a hazard/junction/standstill so that it double declutches quicker and holds the gears longer giving one a swift exit ...
Certainly no turbo lag.

I drive in Command shift 90% of the time, I find the torque converter far to lazy on the TDV8, yes it smooths out power delivery very nicely, but imo giving far too many revs for what is a very low down torquey engine.


I'd say your lag is in part down to the slow gearbox and numb accelerator pedal. Try driving in command shift and let the torque converter lock, drop down to 1200/1300 rpm in 3rd and then put your foot to the floor (not right to the floor as this will induce kick-down/open the torque converter and change a gear) you should feel a pretty decent surge by about 1600+ rpm that stays constant to a bit over 3000rpm.

AFAIK, the EGR system causes some of the lag, and can be disconnected as per the thread on disco3.co.uk: http://www.disco3.co.uk/forum/topic19800.html