10psi boost creep!!!!

[87vr4]

heres the problem,

i had my car setup & tuned in qld during summer & it ran really well on 18psi, would hold that boost all day every day solid as a rock,

just before i left to join the raaf i replaced the stock intake that had been left on during tuning with an almost striaght 3" pipe & found that the car started to run 20+ psi & hitting fule cut (set haltech map limit so it doesnt blow up) being short on time i just left it & toddled off for a bit of military re-programming.

now im down in victoria, on the mornington penn, where is always raining & always cold as fuck & im getting some very nasty overboosting iindeed! after much playing with the ebc in the haltech iv cracked the shits & removed the bcs from the setup & run straight from the vaccume source to the accuator in an attempt to just run stock boost untill i can sort this controller out. Now the creep is even worse! still out to 20+psi by around 6k

the turbo is a genuine evoIII 16g
its got ss headers & a low resistence intake
dual dump which joins about 20cm down

the only things i can come up with are -
vaccume sourse is the plenum, so for some crazy reason im getting a pressure drop over the outlet im using. thus allowing the gate to close back up again (unlikely) but im going to tap into the cooler pipe just after the cooler & get my vaccume source from there soon.

or

the setup is so effecient now that the factory wastegate simply cant bypass enough air to maintain a solid boost level


any other ideas? cos im frest out im not keen on porting the wastegate or fitting an external gate, but it may need to be done

 

[CLuTZ]

the setup is so effecient now that the factory wastegate simply cant bypass enough air to maintain a solid boost level

:wink:

 

[87vr4]

how much room is there the port the wastegate opening on this puppie ? & is it possible to get a bigger flap to fit onto it ?

 

[VR-4-PLAY]

E3 B16Gs are notorious for boost creep with high flowing exhausts.

Going for a ported or custom dump will help, but ultimately the Wastegate opening needs to be ported ( GTPUMPS 16g already comes with an enlarged wastegate because of this)

Either that or go for an external gate like the Kiwis seem to always do :wink:

 

[87vr4]

i dont think an externals going to be easy if i keep my ss headers,

i dont want to get new headers cos it will no doubt change where my turbo sits which means i'll prolly need to make some mods to the exhaust to get it to bolt up again, only needs to be 3 or 4 mm out to not bolt up anymore lots of buggerizing around

does anyone know how much bigger than 31mm the standard flap is? or will i need to get the 34mm job... and who would i get one of them from ?!

 

[to4garret]

i had major creap with my old 16G

i got the housing ported, i had the wastegate hole enlarged by about 1-2mm, did change flappers at all. its not actually the size of the flapper thats the major restriction, its the flow into the wastegate hole which is the biggest problem.

smoothing out the entry will have the biggest impact.

 

[87vr4]

did the porting etc fix the creep? well enough for it to be managable anyway..