Turbo issues

[FlashGTI]

Hi all, I have just had my turbo changed for, what i was told, was a newly recon hybrid turbo with a gfb DV+. There was no signs of use etc at all on the turbo. Since picking the car up the it now boosts to around 22psi (original turbo boosted to around 14 psi) and when on full boost it just shuts off every time like it has reached a cut off, the car will keep accelerating but just with no boost.
I can then ease of the accelerator and it will then boost again and cut off, there is not engine management light coming up on the dash or other issues.
The garage that fitted the turbo (i supplied the parts) reckon it could be the mapping of the engine and the ECU shutting it off due to it thinking over boost or too much fuel being required.
Car is already stage 1 mapped, but I spoke to the company and they can stage 2 it to see if that sorts it out but will cost me £220! and it might not help at all.
The N75 isn't that old, but would that actually fail exactly the same time as the turbo is fitted!?
I am wondering though if it could be the actuator, is there any way I could test this theory?  I dont have VCDS, I only have that Carista fault diagnosis not sure what I would be looking for on there.

Has anyone experienced anything like this before? any ideas or help would be appreicated!

[pudding]

Probably fuel cut. To run 1.5 bar boost you need an uprated hpfp and a proper map to go with it.

[FlashGTI]

OK, So i have a few things to try one by one maybe. I will just need to try and get hold of an uprated hpfp, any ideas where best to get one....although I am on a budget. would and ED30 HPFP work?

Also I was just told by someone they reckon it would need to be set up correctly on a rolling road with custom map to run a hybrid turbo... I thought a hybrid turbo meant you could bolt it on as is and upgrade as you go.

[pudding]

The pump is the same on all cars (GTI, Cupra, S3, ED30 etc) so you'll need to get an internals kit. Most people have good luck with the VIS motorsport kit.

Nope. Hybrid means it pushes a lot more air than the standard turbo, meaning it will need a map to suit it's flow characteristics.  Before getting it mapped would be the time to add other supporting mods......intake, downpipe, intercooler etc.

If you're on a budget, this is an expensive path to go down.  Maybe consider swapping the hybrid for a standard turbo and take time out to review your options?

[ald1717]

could just get it mapped on dyno properly will cost £300-400 but you wont get the benefit of the hybrid power and will be resticted to around 275bhp max until the hpfp runs out, or you can add internals at an additional £300-400 and get around 330 bhp for the extra doe.