Details on the car are below, but the short version is the car seems a little lazy onto boost but then makes good boost/power after 4-4.5krpm.
It will build up to about 10psi in 2nd and 3rd but then at 4k-4.5rpm it will jump quite noticeably and quickly upwards and seems to “come alive” and want to make power/pull properly. I wouldnt say it’s slow to rev in general and drives fine with no DTCs but there’s something amiss and much more power/response/boost on tap after this point.
When I wound some more preload onto the wastegate for testing that jump could be from 10 to say 18psi (I backed off quickly) but the point is more so that the boost building and power delivery becomes very rapid after 4-4.5k rpm and is a bit soft/lazy prior.
This tune (OEM Denied stage 3) should be targeting 14-16psi in 3rd and I’ve had it confirmed from another user of that tune with the same mods that his car hits 16psi well before 4k rpm and holds it as you’d expect.
For a quick background, I recently rebuilt the T5 for a Ford Mondeo XR5 project the engine is nearing 900ks, is fully broken in, has good compression (160-165psi), is now running its full synthetic 5w-40 oil (clearances were opened up a little so 0w was a bit thin).
The car/engine had done 236ks and suffered multiple spun bearings when I got it, not everything was replaced new. The wastegate, TCV, VVT, pulleys, VVT solenoids, cam position sensors, MAP sensor etc are all original. The turbo core is fresh, rings, bearings, rod bolts, all seals/gaskets, PCV lid and diaphragm, clutch, flywheel bolts, oil cooler etc are new. I also have another running parts car here that I can take things from.
Originally the issue was that it would build boost a little slowly, not super slow, just not immediate like these are known for and how it behaves after 4-4.5rpm and hold around 10psi in all gears, some wastegate pre-load now has it wanting to jump once it gets to 4-4.5k rpm so I know it was a bit soft to start with (it was bench tested and seemed a little weak). I still need to take some pre-load out so our max is 15-16psi in 3rd, I’m aware of torque limiting in 1st/2nd and this tune does not remove that.
The car has a dump/cat, airtec intercooler, 440cc injectors, pod filter, GoFastBits CBV (fully recirculating and with some extra pre-load on the spring), RS oil cooler, RS clutch, and was using the turbosmart 3port TCV but I have swapped back to stock as it was shown to be leaking out the wiring/bottom (not the 3 ports). I have also swapped out the MAP sensor during testing.
I’m starting to suspect it’s a timing/VVT issue, when the engine was built the gears were not removed from the camshafts and I used the locking tools to set timing, the marks all appear to line up as you would expect.
Is there a way I can test the solenoids or pulleys/VVT operation? I have ForScan here and I have a spare set of solenoids and gears but would like to avoid removing the gears given the work that entails, in retrospect the gears and solenoids were not specifically cleaned during the rebuild, could this be an oil pressure issue into the VVT hubs/solenoids?
Am I way off and there’s something else going on? I have plenty of experience with Turbo JDM cars but not this Volvo platform, if the car had a boost leak I would expect it to build slow/bleed off or build fast then bleed off badly, not build semi slowly, then shoot up quickly after 4-4.5k rpm.
All assistance welcomed 
PFA
