Ever since I bought this truck I have had concerns about the proper operation of my turbo. When I first purchased it I took it off and found the unison ring seized to the housing so I know it wasn't moving like it should. After cleaning and reassemble I never noticed any improvement in performance so that got me to wondering if it was functioning properly. Put gauges on it to monitor VGT and it was making boost so I pretty much figured it was doing what it should. I drive it very little but I try to take it out at least once a month and wind her up. I have always noticed I have never seen more than about 21lbs of boost. Most of the time when I stand on it I see 18-19lbs. and no more. The VGT fluctuates but the numbers aren't what is listed in the tech section. Mine are pretty much...
idle - high 50s low 60s %
cruising - mid to low 40% reading 1-3lbs boost
Hard accel - 38% and a bit lower. This mornings ride to work it went down to 19% but that was just after I lifted from a hard accel.
Are these numbers in fact ok and if not what would be a suggested diagnosis/repair? I'm new to these engines and with the horror stories I sometimes wonder if I have a legit problem or if I am just obsessing over a non issue. What yall think?

 

Pic attached.

 

Thanks Mark. Seems my actual numbers are pretty much with yours. I was basing my concerns with the VGT% you had posted in the tech section. Now I will return to not worrying about that issued
My unison ring has a slight amount of wear in the slot where the actuator hits it. Could that possibly be a reason my boost pretty much tops out at 20lbs?

 

I would say, probably not. If the unison ring was hanging up on one end of the slot it would ether be wanting to stay in the vanes closed position or vanes open position. One end would make it not tend to open at all or the other scenario would be hung it the open position. Maybe it would create a lag issue at most unless the notch was huge?. I fought with my turbo trying to solve just the issue you have. New "upgraded" compressor, unision ring, vanes vgt, leak checking, ect. Maybe there wear some issues but I did I get my truck running great but same 20 psi max boost. That is until I towed a fairly heavy load at which time it got to 27-28 psi. Since then I realized that it could go even higher but I back off to keep in around 25. (my is not studded), I think is has something to do with the ford flash where it was made an inferred EBP scheme. Anyway, some of my online research had some guys getting 30 with no problem while not towing and other guys saying it will never get more than 20 until it is "called for". I know my truck before the flash would easily break traction from low speed. Now you can floor it from dead stop and in pulls off nicely but not close to loss of traction but chirps the tires and really takes off when it shifts to second gear. This is bare not towing. While towing from dead stop I can get wheel spin pretty easy. I have no explanation for this but really it's a good thing. I wore out my first set of tires because is was fun. not fun now but maybe better. Anyway i hope this gives you some peace of mind or maybe more questions?