low timing boost creep? 350z

hi i have a 350z turbo customer has installed a tmr kit 2nd hand

i have a 5psi spring in it hea said somebody tuned it on the previous car then fitted to current car

its running a link g4x

i have an issue where it spikes to 10psi that i have the boost cut set to

ive gone over everything even just ran gate pressure straight to manifold still same issue.

im starting to think it may not have enough timing and making a anti lag affect.

here is a pic of my timing map what do people think

i dont really play around with these high comp boosted cars.

any help would be great. thanks dan.

Is there a log showing the problem? What are the conditions? (i.e. Engine Speed, Throttle Position, Manifold Pressure, Boost Pressure prior to spike, Gear, etc? )

4th gear dyno pull

Afr is on target

3500-4k is where boost comes in with no boost solinoid goes straight to cut 10psi.

Can you describe the turbo kit in more detail?

Turbo, turbine housing specification, wastegate size, exhaust, manifold design. I'm not familiar with those specific engines on boost but that timing does look fairly modest, the turbo kit/wastegate may not be helping though.

Dan I tune these. You're not low enough on timing to be causing something that wouldn't be happening anyway.

That kit doesn't look great to be honest, but hopefully there's a simple solution. Perhaps the wastegate doesn't have the spring in it that the owner thinks it does, or maybe the diaphragm got torn swapping springs. Another common issue is a plug falling out of an unused port.

thats good to know mike

i did swap put the spring myself went from the so call 8psi spring to a 5psi but i think i may be to long will try to get a smaller one that is correct

thanks for your input thanks

If it's easy enough to change, take the spring entirely out of it and see what it does. If the wastegate position and size aren't correct it will still make boost (and possibly overshoot your target)