I have been trying to figure out a problem with a turbcharger giving too much boost. Even with the wastegate puck opened all the way gives this L28 20+psi. At first I thought maybe the bleed hole was too small, but it is 7/8", should be big enough to bleed a fair bit of exhaust pressure?...
Now I am thinking maybe the turbo itself is a problem, it is a hybrid t3/t4 however I have no idea what the specs are on it. The compressor housing is quite large and has a 3" inlet and 2" outlet, however the exhaust outlet is only 2" Is it possible that the compressor housing is far too big for the turbine housing? A small exhaust wheel would get the compressor going very quickly (which is does..) but once the engine pushes out the exhaust it chokes through a small housing causing a pressure build up inside the engine and therefore the 20+psi right away...
Any thoughts on my "theory"??