Trimming the back side of the flapper door arm allows it to open almost 1/8" wider.

 

Nice...

I thought about doing the same thing to my BNR when i got it, but at that time, i was getting the friggin Haltech figured out, the motor back in the car, the battery to the back, and I didn't need another headache, so i figured the 35mm port and flap that bryan put in will just have to do, but the door doesn't appear to open very far before hitting the wall.

 

I roughed it in with a 4-1/2" angle grinder, then finished it with a file.

The trick is protecting the housing to back plate sealing surface.

With the MBC bypassed, boost is 5-6-6-6-6 flat.

 

How would triming the the top of the flapper door comprimise the sealing surface? I am not sure what you are talking about.

James

 

You're working in the housing, very close to the back plate contact face.
With no gasket there - one nick & you've got a leak.

The second picture shows the clearance.

 

I don't think it's necessary, and it compromises the strength of the wastegate flapper.
Have you ever seen one crack into pieces?
I have.
Just by porting the wastegate passages, we've gotten an H-trim hybrid to boost only 2.5psi!


-Ted

 

What did you boost (sans controller) before this modification?

 

Completely stock: 5-6-7-7-7
Gutted cats: 6-9-11-11-11
Ported waste gate & flapper clearanced: 5-6-6-6-6
Stock boost control removed, MBC in line: 9-10-11-11-11

I found another picture:

 

I also cut a little metal away from the back plate. Not much....but maybe 1/32" of metal. Put a little grease on the wastegate flapper and just ground away some metal where the grease marks were on the back plate.

James