To get an estimate I would use the ideal gas law (PV=nRT). Assuming constant volume and mass, you can use T2=T1(P2/P1).. Assuming 60ºF inlet temp (288.7K), and a pressure ratio of 2.22 (32.7 PSIA/ 14.7 PSIA) the outlet temp would be 695ºF (641K). To figure out the heat generated, you would use Q=mCpdT (Heat = mass x specific heat x temp change.)
m = density x volume so 1.225kg/m^3 x .00416m^3 (assuming a 3" intake tube 3 ft long) = .0051 kg ..
Q = (.0051kg)(1 kJ/kg K)(641K)
Q=3269.1 J = 3.1 BTU
..Just an estimate