What is the normal max boost on a 550 HP, C-15, 6NZ engine?

Altitude also makes a big difference in boost. Much more boost at sea level vs. 10,000 feet.

Air gets thinner as you go higher.

 

I have a 01 pete with 6nz c-15 also. Have the pitts power box on it. Without box switched on, yes around 30 boost. Switch box on and depending what setting i have box set it will make 40 to 45 boost. Higher settings will go higher yet. The higher the settings obliviously more torque and hp. I also have a non wastegate larger turbo. But the box works well with stock turbo . Power box easy to install and been using for about 10 years, no issues whatsoever.

 

From the 6NZ and MBN single turbos I've driven, never seen one go higher than 25-27 lbs.

My C-13 (first year ACERT) with twins has topped out at 60 lbs before.

That's perfectly normal for a 6NZ, and pulling a camper, I'm surprised you can even get it that high. Strikes me as a truck that should still be pulling loads down the road and working for a living.

 

You have a nice retirement setup.! Good for you. Blessed!

 

Hi mr cob. Yep that’s all I get too. 27-28 lbs. is all you’re going to get and that’s normal. If you have a waste gate, pinch off the hose and you can really wind it up, but I DO NOT recommend it. It happened to me once . Had no choice. Waste gate took a dump and I wanted to get home. Babied it all the way and fixed it that night. Nice looking unit by the way