ej257 6766 lag issues and 38mm wastegate

hi i have a 67mm turbo t3 1.06 on en ej257 im using a pte 40mm wastegate

is taking a long time to build boost i have max springs on the wastegate around 30 psi worth of springs it will boost 21 psi at gate pressure at around 6000 and holds to redline??

but when i try to boost more than 26 psi it takes up to 6500 sometimes 6800 to achieve full boost in 4th gear

the car dont have a boost leak so could it be a too large ar on the t3 1.06 or too small of a wastegate

check too see if the wastegate is being pushed open.

It could be a leak somewhere on the intake or exhaust system(s), too large a turbo' and/or A/R, it could be something stopping it getting to full throttle, it could be a restriction somewhere such as a kinked hose or one that's sucking closed, it could be a restrictive charge cooler, could be a restrictive exhaust, could be something else... As Kyle suggested, it could even be a leaking wastegate.

I'd suggest giving it a thorough checkover from filter/intake to exhaust ip, not forgetting ALL the hoses and pipes, and the wiring. It may well be the A/R which is definitely biased towards high rpm - especially if the build isn't set up to produce the exhaust flow needed, but the check will help remove other possabilities.

How big is the intake filter, is the intake pre-turbo collapsing? Has a rag got into the intercooler end tank? Are you 100% a coupler or joint isn't leaking on the intake side or a gasket on the exhaust side isn't leaking. What diameter is the exhaust system? Does it have a catalitic converter, what size/construction?

That turbo will have a high boost threshold on that motor vut once it's on it should make spring pressure.

couplers are ok boost leak test at 35 psi

turbo intake open no filter

exhaust 3 inch hood exhauat

how could i know if the wastegate is opening prematurely?

engine build 9:5:1 compression 2.5 bc 272 cams high flow heads

the turbo is a turbo lab gt35r chra with hx40 67mm turbine shaft and 67 mm compressor wheel t3 1.06

i know 67mm turbo with t3 82 spool at 5000 rpm and was told that the 1.06 was 500rpm laggier so i was expecting to have full boost between 6000-8000 but is way laggier

setup below

how could i know if the wastegate is opening prematurely?

There are wastegate position sensors which allow you to log that information.

Lag and boost threshhold are two different things. Perhaps the best way is to suddenly apply apply full throttle, from cuise, at different rpm, and note the different delay before the boost comes in.

There are certainly a lot of people who have been able to come onto boost with that housing, at around the 4-5k mark, but if the vehicle isn't able to produce the level of exhaust gas (power) required to spin it, it will come on higher. For some engine setups, it could be 500 rpm difference in the boost threshhold, but for others it could be quite a lot more.

What power level do you expect the engine to produce?

issue is with boost threshold

im at 616hp 33 psi

goal is 700 37 psip

Any chance your blow-off-valve isn't adjusted high enough and is leaking... Are you running on a dyno so you can look carefully for leaks during a WOT run?

running on dyno no leaks the only doubt i could have would be the wastegate crackin open but have no way to verify that

car runs no BOV

Can you see the wastegate dump tube while you are making a run? did you forget the sealing ring the wastegate valve seats on to. I've seen this before and it causes similar issues to what you are having. Boost basically comes on very late once the exhaust overcomes the huge leak and starts driving the turbo.

You can have someone that is brave enough to put their hand near the exit of the wastegate to see if they feel exhaust coming out. (wear something like a tig welding glove) Or ziptie a shop glove to the end of the dump tube and watch it inflate! LOL if it blows it off before hitting your boost target you know it's opening prematurely. idk, there are several ways to verify.

Where did you make the boost leak test? From the compressor inlet?

Another thing is to check the hoses between waste top ports and boost solenoid. That route isn't tested when you are making a leak test.

because its closed loop between wastegates and boost solenoid valve.