Right, its a long story, so ill try and keep it simple.

New hybrid turbo was fitted a week ago, took it to Shark yesterday and mid mapping it was noticed requested vs actual boost wasnt adding up right. Shark kindly ran smoke test on boost pipework, checked actuator was holding pressure and checked accessible vacuum lines to no avail. Running out of time, they turned the fuelling and boost down and sent me off to get it sorted before returning to complete the mapping.

Now the car builds boost, but very slowly, and only hits peak boost high up the revs. It was suggested that its almost like its being powered by the exhaust side.

So, things checked:

Boost pipework - no leaks

No EGR, so cant be that.

Vacuum lines pressure tested.

Actuator checked it holds pressure.

Actuator movement is ok.

Actuator pulls shut to stop screw on rod when car is running, showing vacuum box is ok.

I've been out going over what i can today and tried a MAF unplug test, and notice no massive difference between it being plugged in, to when its not plugged in. However on the phone app Torque, no error codes are held, or lights on dash when unplugging this. Is this right?

Videos below to show the cars behaviour, and with and without MAF (excuse the gauge mounting! Its normally in my glove box for keeping an eye on things!).

WITH MAF:

WITHOUT MAF:

Anything else i can try? I dont have VAG COM, but do have Torque and ODB reader.

maybe spec of hybrid is different?

Before the new turbo what turbo did you have and was it mapped?

Also what turbo have you now got?

It used to have a standard KKK turbo with a stage 1 map by RTech, which was fine condition, i just wanted to go Hybrid. Shark removed the old map and started a fresh, got a few maps on then noticed it wanst boosting properly.

Its a reconned PD150 Garret. Its a 'stage 2', which is bigger impeller, and cutback exhaust side.

Its the way it boosts which is odd, very linear, whereas i expect a shove of boost at 2krpm, then for it to slowly tail off, instead of what its doing now where it slowly builds boost up into the rev range.

Right, its a long story, so ill try and keep it simple.

New hybrid turbo was fitted a week ago, took it to Shark yesterday and mid mapping it was noticed requested vs actual boost wasnt adding up right. Shark kindly ran smoke test on boost pipework, checked actuator was holding pressure and checked accessible vacuum lines to no avail. Running out of time, they turned the fuelling and boost down and sent me off to get it sorted before returning to complete the mapping.

Now the car builds boost, but very slowly, and only hits peak boost high up the revs. It was suggested that its almost like its being powered by the exhaust side.

So, things checked:

Boost pipework - no leaks

No EGR, so cant be that.

Vacuum lines pressure tested.

Actuator checked it holds pressure.

Actuator movement is ok.

Actuator pulls shut to stop screw on rod when car is running, showing vacuum box is ok.

I've been out going over what i can today and tried a MAF unplug test, and notice no massive difference between it being plugged in, to when its not plugged in. However on the phone app Torque, no error codes are held, or lights on dash when unplugging this. Is this right?

Videos below to show the cars behaviour, and with and without MAF (excuse the gauge mounting! Its normally in my glove box for keeping an eye on things!).

WITH MAF:

WITHOUT MAF:

Anything else i can try? I dont have VAG COM, but do have Torque and ODB reader.

How come on ya pics the the one with the maf plugged in is revving higher than the one without the maf plugged in

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How come on ya pics the the one with the maf plugged in is revving higher than the one without the maf plugged in

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They are video links. The one revving higher in the PREVIEW pic is because the car is moving - see speedo.

What about, the vac box on the top of the strut? It contains the N75 which is what controls boost.

It was the cause of my spiky big overboost so could also contribute to a lazy underboost?

Shark tested this by taking the feed off of the 'box' and manually pressurizing it while running - but i could try this to eliminate fro the list when i meet up with trebormint from here on Saturday along with the MAF.

Whats the odds its the actuator rod needing adjustment?

Shark tested this by taking the feed off of the 'box' and manually pressurizing it while running - but i could try this to eliminate fro the list when i meet up with trebormint from here on Saturday along with the MAF.

Whats the odds its the actuator rod needing adjustment?

Could try my vac box to see if it makes any difference, though I doubt it, and maybe the MAP sensor...but not my turbo! lol

If these are proven to be working, then itll be down to the turbo. Its moving freely, and 'actuates' as it should, so in my process of eliminiation, its got to the be actuator rod which actually controls the veins in the VNT which therefore control the boost?

The VNT cant be seized/stuck with soot as its a fresh build.

I wouldn't adjust the actuator rod mate I did this on me allard vt5 hybrid and it boost it bag off to about 3bar so turned it down a bit and then it wouldn't boost at all best way if it is that is to send it back to tditurbos and ask them to check it all over mate

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Or speak to someone who knows how to set them up. Dark side should be able to help.

Adjusting the actuator usually voids warranty, get the turbo builder to sort it under warranty.

Oh, im not going to adjust it myself, im just trying to get to the bottom of why its doing what it is. Im in talks with the turbo suplier who is being very helpful, but im trying to rule out everything easy as id like to avoid removing the turbo again!

Oh, im not going to adjust it myself, im just trying to get to the bottom of why its doing what it is. Im in talks with the turbo suplier who is being very helpful, but im trying to rule out everything easy as id like to avoid removing the turbo again!

Well practice makes perfect! Be a dab hand at removing and fitting turbos soon.

Hopefully he has an idea as to why it's not working.

Thanks all for the replies. Im going to test MAF and vacuum control box on Saturday and go from there. Ill keep you posted.

I'd try the MAP sensor if you can.

I'd try the MAP sensor if you can.

We will do using mine as a temporary donor.

Cool. Great thing about the club. Always people happy to help

Cool. Great thing about the club. Always people happy to help

Indeed and also its Christmas!

Cool. Great thing about the club. Always people happy to help

Sure is a great club to be a member of I'll document the findings for future users reference.

MAP, MAF and vacuum box checked and swapped out with no changes proving this all works - Nothing left to check, literally! So, its back to the turbo, it must be the actuator/actuator rod/VNT mechanism giving the damn right lazy boost!

Will go back to turbo builder and see whats said, but it looks like it'll be another turbo off spannering session to look forward to. Joys.

MAP, MAF and vacuum box checked and swapped out with no changes proving this all works - Nothing left to check, literally! So, its back to the turbo, it must be the actuator/actuator rod/VNT mechanism giving the damn right lazy boost!

Will go back to turbo builder and see whats said, but it looks like it'll be another turbo off spannering session to look forward to. Joys.

We should start our own garage!

We should start our own garage!

Too true! Well i will be arranging for the turbo to be checked over which has been agreed by the turbo builder. They are getting a new (improved) vacuum gauge in as we type to check that the readings on the actuator are correct and make adjustments where necessary.

Unlikely to get this checked (frustratingly) until after xmas now due to the poor timing. Will update when i get more info.