mhi big 16g question

[Sandman817]

I have a mhi big 16g turbo with a ported turbine housing and 34mm waste gate flapper.

My question is, should the flapper be able to spin on its seat when it is closed?
And when i apply 12 psi to the WGA nipple the flapper opens but not much. Is this normal? also, the wga rod rubs against the actuator housing.

My main concern is going to be boost creep on a brand new motor setup that i am in the process of building.
If you guys need pictures or a video let me know. Thanks

 

[brute]

I have a mhi big 16g turbo with a ported turbine housing and 34mm waste gate flapper.

Just to be clear, only the throat of the housing is ported? I'm assuming the wastegate hole is larger as well.

My question is, should the flapper be able to spin on its seat when it is closed?
And when i apply 12 psi to the WGA nipple the flapper opens but not much. Is this normal?

It seems to me that if the flapper is spinning while closed that the actuator is not putting enough pressure on it to keep it closed. Have you done any type of check to see if the flapper is leaking air?

In terms of it not opening a lot, pictures may be helpful. Does it open like 20 degrees? 45 degrees?



It sounds like most (if not all) of your problems can be traced back to the actuator / actuator arm.

 

[Sandman817]

yes the hole is larger and as well as having a physically bigger wastegate flapper.

And as far as getting a picture of it while pressure is applied, i wont be able to do that untill tomorrow when i get back to work tomorrow

 

[JusMX141]

Normal MHI actuator movement is only around 3/8" max, which is hilarious considering the amount of people who grind away part of the housing to allow the flapper to open "all the way" then claim it actually does something to control creep.

 

[Sandman817]

the flapper seemed to open all the way at about 20psi or 25psi, i cant recall right now.

 

[Sandman817]

The wastegate is ported on it along with the bigger flapper but it still seems like this is definetly not enough area for the exhaust gas. To escape quickly enough. I am going to be running this turbo with a fp race mani, or a tubular mani, 274 cams, o2 housing w/ dump tube and a 3" dp. I just don't want to hit fuel cut on my brand new engine I'm building