PD150 hybrid "lag/hesitation??" I don't know...

[sion_kwl]

I have a weird acceleration problem with my PD150 and both me and the tuner are a bit stumped...
spec:
PD150 stock engine and injectors
EGR removed
GT1760 hybrid turbo
upgraded intercooler pipework and FMIC
Limited to 1.9bar currently.

symptoms:
First full throttle acceleration after it's been turned off, or I've been sat in traffic for a while, it feels like hitting a wall past 3000rpm, it pulls, but with stock power levels. repeatable on the dyno. While driving it feels as if there's a massive boost leak, but no apparent boost leak, and the vag-com boost logs are fine.
On the dyno we just repeated the run and it worked perfectly, and the same happened every time. while driving, if I just come off the accelerator and get straight back on it, full power again.

this has only started happening since the turbo upgrade, so naturally I assumed the turbo or associated vac line was at fault. but the vanes move freely, and I replaced the vac lines when I replaced the turbo.

if anyone has any ideas that I could look at I would be most appreciative

 

[Seatmann]

Maf maybe? Even without throwing a fault code they can cause random power issues. One off any PD150 should fit straight on to try

 

[sion_kwl]

Cheers for the reply. I ruled out MAF because it's consistently after an extended period of zero boost. I'm starting to think maybe the vanes are sticking, either due to the vanes being stuck, or an actuator or vaccuum problem. Reason for my theory is that although it's making boost, past 3000ish RPM the closed vanes are creating a restriction on the exhaust side, massively reducing actual airflow. This would be consistent with an increased turbo noise I have now noticed when this happens.

I'm just hoping for a sanity check on my theory

 

[Sharpy]

Not wanting to worry you but having spent quite a long time talking to Darkside Developments they wont fit hybrid turbos to PD engines as they say they dont work very well with this type of engine for some reason. Hence I am going for a bigger non hybrid turbo. I dont know anymore than that though....

 

[sion_kwl]

Yeah, we found that on the dyno, it was a pain in the arse getting a base map working on it, not helped by this issue... but once we got something together that works it started to go better. I need to fit a new Map sensor and we can throw more fuel and boost at it, but I want to get to the bottom of this first as it's annoying the crap out of me...

 

[Andrewwright]

1.9bar....you sure the turbo hasn't shat itself. I have the Same issue, stock turbo, 1.7 bar with oil in the intercooler pipes = dead turbo...will still boost to 1.1bar ok lmao.

Anyone with a stock pd150 turbo for sale let me know

Sent from my Nexus 6 using Tapatalk

 

[Seatmann]

Some oil in the boost pipes is normal, comes from the ccv but if it's a lot then yeh, pooped lol

 

[Andrewwright]

Some oil in the boost pipes is normal, comes from the ccv but if it's a lot then yeh, pooped lol

Far to much unfortunately.

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[Seatmann]

My impeller hadn't hit the housing so was able to rebuild it, got the parts from turbo rebuild. Worked a treat

 

[sion_kwl]

No, it's limited to 1.9 by the tune coz of the Map sensor, I didnt take into account atmospheric pressure so thought a 3bar map sensor would be fine... Doh...

Yeah having a bit of oil is normal. If you haven't got a catch can installed, and even then there'll be a small misting if you have it plumbed back into the intake

Anyway I got to the bottom of the issue, the new vac line I ran for the actuator was too weak and was collapsing when the engine bay got warm

I do actually have a perfectly good stock turbo for sale though

 

[Seatmann]

Haha its the stupid little things, happy days though lol

 

[Andrewwright]

No, it's limited to 1.9 by the tune coz of the Map sensor, I didnt take into account atmospheric pressure so thought a 3bar map sensor would be fine... Doh...

Yeah having a bit of oil is normal. If you haven't got a catch can installed, and even then there'll be a small misting if you have it plumbed back into the intake

Anyway I got to the bottom of the issue, the new vac line I ran for the actuator was too weak and was collapsing when the engine bay got warm

I do actually have a perfectly good stock turbo for sale though

Message sent

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[Zardoz]

Anyway I got to the bottom of the issue, the new vac line I ran for the actuator was too weak and was collapsing when the engine bay got warm

What replacement vac lines did you buy? I've a feeling the coloured ones I bought to replace mine last year are a little soft and might be causing me issues.

 

[sion_kwl]

I had some hard plastic lines left over from fitting my mates air ride that I used in the end

 

[AndrewJB]

Not wanting to worry you but having spent quite a long time talking to Darkside Developments they wont fit hybrid turbos to PD engines as they say they dont work very well with this type of engine for some reason. Hence I am going for a bigger non hybrid turbo. I dont know anymore than that though....

Darkside would say this so you can buy a bigger turbo off them, People have been fitting Hybrid systems to the PD130/140/150/160/170 since like 2006 with good results, obviously no where near as much power as a system like GTB2260VK but decent power for the £££ the turbo hybrid costs.