  We derive constraints on the tensor to scalar ratio and on the background
charge of the warped throat for DBI inflation driven by D5- and D7-branes
wrapped over cycles of the throat. It is shown that the background charge well
beyond the known maximal value is required in most cases for DBI inflation to
generate cosmological observables compatible with the WMAP3 data. Most of the
results derived in this paper are insensitive to the details of the inflaton
potential, and could be applied to generic warped throats.
