Scroll down and the fuel consumption of DB605 engines can be found.
http://mitglied.multimania.de/luftwa..._varianten.pdf
For example for the DB605A - C
At 5.7km, 2100rpm, 1.00ata fuel consumption is 250l/hr. At the same altitude but 2800rpm, 1.42ata, the consumption is 450l/hr.