Galant vr-4 with 16g, wont make over 21 psi

[Mitsuturbo]

I have checked for boost leaks, compression, leakdown, wastegate, and BOV. The small 16 that is on the car is about 6 years old, and the turbine housing is showing cracks internally.. I'm running about 9:1 compression, and have a Tial gate, with a Godzilla BOV... 2.5" upper IC pipe, and stock intercooler.
I'm wondering if the stock intercooler is not allowing that much flow, and if maybe the turbo is just worn out... however the turbo compressor housing and wheel look fantastic, and spins great... just as it should.

Has anyone else with a GVR4 had problems with not being able to make over 20 psi with the stock intercooler... or a turbine housing in less than perfect condition?

I personally rebuilt my engine less than 10k miles ago... and my car being as fast as it is reflects that everything seems to be in good working condition, as do the boost leak and compression tests.

Any advice would be appreciated and considered seriously.

Thanks in advance...

Mitsuturbo
1411/2000

 

[Mitsuturbo]

Forgot to mention... the upper IC pipe and BOV are new additions (which did help a bit).. i found that my stock bov was starting to leak at 16 psi, so i did the upper ic and bov today.. boost will now hold steady where it used to hit 17 and drop to 16... or if i turned it up, to 20 and drop to 18... this was due to the BOV and the POS Deltagate i had... the gate was replaced with a Tial yesterday. I also have a ported head and ported cyclone intake manifold with anything resembling secondary runners removed.

I suspect either the turbo or the intercooler.

Yes i have enough supporting mods to accomodate over 20 psi... it just won't DO it.. even with the Tial completely disconnected from a pressure signal.

 

[Mitsuturbo]

I am considering "hotpiping" the intake tract tomorrow, just to see if it has to do with the intercooler and/or piping.

Any experience with this sort of problem would be appreciated. Sorry about all the posts on this here.

 

[Mitsuturbo]

haven't tried the hotpipe option yet... maybe tomorrow..... hope someone has some helpful suggestions before then...

 

[honduraneclipse]

16 G are not so effective after 21 PSI you have to definetly bring the car to a dyno ... you can run the same amount of boost and run in the 12's which you should be in ( with your mods of course). and oh yes get a FMIC everyone is doing it

 

[Mitsuturbo]

fmic is planned, of course.. i know that over 21 psi a 16g would not be efficient.. but i am concerned as to why it is not going higher... i have seen old 14b's hit 26 psi... sure it is incredibly hot air.. and dangerous to run... but i would think that a 16g could (inefficently) spike to 30 psi. I'm wondering if my efficiency is being affected due to "something i may have missed"

 

[Mitsuturbo]

Found the problem.. some assinine person did a HORRIBLE job welding my stock wastegate flapper shut (before i got the car) so i took the turbo out today and disassembled it.. took it to a buddies house and welded it shut so it will NEVER come open again.

I am now boosting to 20psi and the Tial gate is WIDE OPEN by 3200 RPM... i am Lovin' it!!