Y pipe leak?
 

OK....first post and I am somewhat of a noob. I have a 2006 power stroke. I just got a SCT livewire 4 in turbo back exhaust , egr delete, headstuds, oil cooler, a 2003 turbo and a coolant filtration system less than 500 miles ago. Everything running great with an insane whistle from the 03 turbo. Going down the road at 65mph and the whistle is gone....start checking gauges and everything is good but not building boost at low rpm...under 1800rpm. Vgt duty cycle ranges from .14 at idle to .47 at 25psi which is about all I can push now....was getting about 32psi full boost. Slight exhaust fumes in cab occasionally. Real throaty exhaust sound now and I am pointing towards the ypipe being cracked....any advice to confirm my thoughts
Thanks in adavance

And it is not throwing any codes

Makes sense to me. . Check for stuck vanes if you have used turbo

Brand new turbo....thanks for the advice

Check your fuel pressure, and high pressure oil, actual not expected. . .when my HPOP was going I lost power and whistle less ( I have 03 whistler I love!)