Boost Issues , Weird

[thilaksharma]

I run a 50trim + td06h style turbo with 7cm ported turbine housing, stock internals, stock intake. I run on megasquirt so its on MAP sensor. Tial 38mm wastegate, stock exhaust manifold , wastegate is on the o2 housing side , 3" downpipe.

1st Issue

I can no longer cruise on the higway on boost. When I half throthle on cruise , maybe around 14 psi , i get alot of surge and the bov keeps on fluttering opning n closing.
I thought it was the BOV, so i switched from the Synapse to the Greddy Type-R, it still has the same issues. If I WOT all the way, it is totally fine.

2nd Issue

I get terrible boost creep with a Profec B Spec II , even if i switch it off.

Things i have tried
1. Directly fit the wastegate with a direct source, wastegate spring is 7 psi, but i get 20+ psi at 4th gear if I WOT all the way, Hoses are new

2. FIT a MBC , its still the same

3. Open up the tial 38mm , dismantle the whole things to pieces, everything looks fine in there.


so guy, do you have any other things that I should try , maybe a 46mm tial wastegate ?
thank you in advance

 

[blade970]

I'm no expert, but I feel like the wastegate is the issue here.

 

[hollywood_ikr]

For your 1st problem, it sounds to me like you have a BOV/wastegate issue or it needs to be retuned, also I recommend you check for boost leaks (it can't hurt)...

I have no idea what the 2nd problem could be since I would've recommended to change to a MBC, bt you say you have done that already.