We investigate the ultrafast nonlinear phenomena of picosecond chirped non-ideal hyperbolic secant pulse evolution in silicon photonic nanowire waveguides with sum frequency generation cross-correlation frequency-resolved optical gating and nonlinear Schr?dinger equation modeling. Pulse broadening and spectral blue shifts are observed experimentally, and they show remarkable agreements with numerical predictions. Nonlinear losses dominate the pulse broadening and limit the spectral bandwidth broadening induced by self-phase modulation. The initial chirp results in noticeable bandwidth compression and aggravation of blue shifts in the presence of nonlinear losses, whereas it plays a negligible role in the output pulse temporal intensity distribution.