Former Ford AutoTrans Eng
Join Date: Dec 2008
Location: Central Florida
Thanked 14 Times in 10 Posts
As the truck starts up the grade the PCM adds fuel to make more power. The RPM stays the same because the torque converter remains locked. The additional fuel makes more heat in the exhaust, and this heat drives the turbocharger faster. The faster turbocharger compresses more air, resulting in more boost. Boost is just pressure in the intake manifold.
Doubling boost does not necessarily mean the air temp is doubled. It isn't a linear relationship, and it is further complicated because there is an intercooler, which cools the air between the turbo and the intake manifold.
Former Ford Automatic Transmission Engineer 1988-2007