Hi,

I made VNT BV39 turbo in delphi with turbo on wastagete kp35.
I ve found another limiter that was limiting my fuel before that i hadnt got in my mappack i made so i have yet more fuel.
The problem is and my question if why is my airflow decreasing with rpms over 2500rpm (M column), my boost is OK and steady , however airflow is decresing.

What can cause that ? Inlet manifold or airbox in filter too restrictive ? Maybe yet exhaust too restrictive ( 46mm pipe without muffler , yet with cat ). Or maybe SOI is too retarded so there is too much hot gases in cylinder that doesnt escape fully ?
Or maybe something else. Is that problem to care of ?

Another question why is there some drop in IQ ( H column ) around 2500-3300 rpm ? I have restrictions on fuel on 51 or 52mg.
What can cause that? I had that "problem" also on IQ 48, 49mg...