The exhaust after the turbo is critical since a turbo motor needs to gain RPM as an N/A motor until it gets to boost, but mainly the exhaust after the turbo acts as a restriction and increases the back pressure in the exhaust manifold. Any back pressure effects the camshaft valve timming and reversion in the combustion chamber and intake, which makes it very detonation sensitive. The first 18-24" is the most critical after that the exhaust flow changes and can be smaller unless it's a race only then keep it big and dump it quick.
Harry
Thanks for the info. We bought a data logger a year ago and decided to get the proper pressure switches and EGT temps to make a quick learning curve. I'm sure we will make quick changes if needed.
