Hey guys, I need some help here.

My throttle body makes a very LOUD/high pitch noise when you open the throttle and at the same time, the car will choke and then rev almost like a delay. The video below doesn't do justice on how loud it is. Seems like it only does it in vac.

This is a stock EVO 8/9 flange that was welded to an AMS f1-I. I did a boost leak test @ 35 psi to the car with the TB open and closed and zero leaks. It only makes this noise when car is running. I have no clue what is going on.

Here's what I think could be wrong but not sure. The flange JMFAB sent me has an ID of close to 70mm. The TB is a ported Buschur ported 65mm. This throttle body gave me zero issues 2 weeks ago on stock intake manifold.

Is it possible the four small holes on the flange are leaking into intake manifold and causing issues? Would it be ok to weld those shut? Any advice or input would be greatly appreciated. This is keeping me from tuning the car/getting it ready for the sport compact shootout Saturday
Video:
http://www.youtube.com/watch?v=_AUPt3pEYPI

Picture of throttle body. Those 3 holes are what i'm talking about on the surface that seals.

 

All you have changed is the manifold - so, it is the manifold.

 

I don’t think the “whistling” sound has to do with leaks, but I think due to the manifold volume upgrade and diff geometry, it should have changed the velocity of the air entering thru the butterfly (especialy with a greater pressure drop) causing the whistling sound. Has your idle/afr's changed just by changing the manifold?

 

maybe its the transition from the tb to the flange and the air going over it.