Disco 2 Wastegate strange behaviour

Michalis Karatzis · Mar 14, 2019

So I decided to try a few things since my boost pressure was not high enough (up to 220kpa on nanocom).
Note the modulator is new and connected and the wastegate moves freely (it just swings with no resistance in both directions)

The actuator was already shortened when I bought the car and I never touched it. You can see in the first foto how short.

First try was with the actuator a bit longer (maybe 5-6 threads longer) Max pressure was around 205-10kpa with this setup.

Second try was with the actuator disconnected and the wastegate kept closed with the help of a cable. With this setup I was expecting some overboost but no...max pressure was 150kpa for some reason. Strange!

Then I shortened the actuator as much as I could (see foto) and the max pressure was 225-30kpa. This is very short and I have to stretch the actuator a centimetre in order to attach it to the wastegate.

What might be the issue? I can't think what is going on and the wastegate behaves like this.

sierrafery · Mar 14, 2019

Record an inputs fuelling log and post it here

Michalis Karatzis · Mar 14, 2019

sierrafery said:
Record an inputs fuelling log and post it here

This might be a bit hard because I have the old steel nanocom and I am not sure how I can record a log

sierrafery · Mar 14, 2019

Read the ambient pressure and see how it behaves under load... i mean does it drop much? what year is your D2, 10p or 15p engine?, is the EGR still on?

Michalis Karatzis · Mar 14, 2019

sierrafery said:
Read the ambient pressure and see how it behaves under load... i mean does it drop much? what year is your D2, 10p or 15p engine?, is the EGR still on?

Ambient pressure always at 99kpa at sea level and 90kpa or lower at the mountains. It's a 2001 10p without EGR

sierrafery · Mar 14, 2019

How much is the air flow when you hit the max boost

Michalis Karatzis · Mar 14, 2019

Hm...now that you mentioned it probably low. Maybe 450-500.

New genuine MAF fitted few weeks ago.

sierrafery · Mar 14, 2019

Then i'd check the turbo cartridge's blades on the exhaust side cos they might be burned out and the turbo doesnt spin up fast enough, mine was also low o boost and i fitted an uprated billet CHRA instead of the worn old core which made a huge difference... see this video

Michalis Karatzis · Mar 14, 2019

sierrafery said:
Then i'd check the turbo cartridge's blades on the exhaust side cos they might be burned out and the turbo doesnt spin up fast enough, mine was also low o boost and i fitted an uprated billet CHRA instead of the worn old core which made a huge difference... see this video

And this is what I was afraid...

Any chance the wastegate doesn't close? Because of carbon deposit or something?

Source for the CHRA?

sierrafery · Mar 14, 2019

It's possibe that theb wastegate to not close well, i've seen that too so you'll hav eto remove the turbo anyway to open it and see. the uprated core which i have is: https://www.turborebuild.co.uk/webs...der-Discovery-TD5-Turbocharger-Cartridge.html , and a normal one https://www.ebay.co.uk/itm/Land-Rov...TD5-Turbocharger-cartridge-CHRA-/331597171645

Michalis Karatzis · Mar 14, 2019

sierrafery said:
It's possibe that theb wastegate to not close well, i've seen that too so you'll hav eto remove the turbo anyway to open it and see. the uprated core which i have is: https://www.turborebuild.co.uk/webs...der-Discovery-TD5-Turbocharger-Cartridge.html , and a normal one https://www.ebay.co.uk/itm/Land-Rov...TD5-Turbocharger-cartridge-CHRA-/331597171645

Great, thanks!

sierrafery · Mar 14, 2019

Other thing which can reduce boost is warped exhaust manifold, after i skimmed mine and ceramic coated it i had to adjust the MBC and release the wastegate a bit cos it went to overboost after the manifold was fitted back without touching anything else

Si Click · Mar 14, 2019

Another vote for the Turbo Rebuild CHRA hybrid billet cartridge. Straightforward to fit as long as you follow the clear instructions to the letter and accurately mark/note the relative positions of the inlet and outlet elements in relation to each other and the cartridge so the assembled whole fits to the vehicle first time. The other tip I got after the event was to disconnect the oil return line from the engine, fit to the turbo and then reconnect at the engine. I must have spent over an hour trying to bolt it to the turbo whilst connected to the engine.

Si Click · Mar 14, 2019

For reference what mass flow figures should a healthy turbo be delivering?

Michalis Karatzis · Mar 14, 2019

sierrafery said:
Other thing which can reduce boost is warped exhaust manifold, after i skimmed mine and ceramic coated it i had to adjust the MBC and release the wastegate a bit cos it went to overboost after the manifold was fitted back without touching anything else

In that case you had exhaust gas leaking from the interface of the manifold to the engine. I had a leak but it was fixed a while ago without skimming.

sierrafery · Mar 14, 2019

Si Click said:
For reference what mass flow figures should a healthy turbo be delivering?

If everything is OK the MAF should be around 600 at full boost, here's a list:

Si Click · Mar 15, 2019

Very useful, thank you

Michalis Karatzis · Jun 5, 2019

sierrafery said:
Then i'd check the turbo cartridge's blades on the exhaust side cos they might be burned out and the turbo doesnt spin up fast enough, mine was also low o boost and i fitted an uprated billet CHRA instead of the worn old core which made a huge difference... see this video

So I managed to check the blades on the turbo and both sides seem fine. The actuator reacts correctly when checked with a bike pump. I don't see any leakages from the exhaust side. MAF goes up to 550-600 when I floor it. MAP was cleaned very recently.

What's next? Maybe a leak between turbo and inlet manifold? Blocked intercooler?

sierrafery · Jun 5, 2019

Michalis Karatzis said:
What's next? Maybe a leak between turbo and inlet manifold? Blocked intercooler?

Might be a restriction in the intercooler if it wasnt ever changed or flushed or a leak through the wastegate port... usually boost leak aftyer the turbo would bring the MAF higher cos the turbo spins fast so the sucction is increasing just that the boost doesnt reach the inlet

Michalis Karatzis · Jun 25, 2019

I am revisiting this thread because the issue is still here. Wastegate actuator is shortened as much as possible (see pic), MAP goes up to 225kpa and MAF up to 460. There is a luck of power of torque/power when going uphill in motorways (looses speed). MAP was recently cleaned, MAF is new and original. No oil in the red connector. Turbo blades look ok inlet and exhaust side.

What's the issue?

Disco 2 Wastegate strange behaviour

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