Just curious....
I do not know how you got that "13.6"-number??Do you have "some mouth to mouth" information, or some facts that can be backed up, that I have missed. Maybe a discontinued pump model?
Haldex-Barnes pump with nominal flow 13 gpm, flows 13.11 gpm at 3600 rpm.
Math:
displacement on the two pump units are 0.194+0.647=0.841 cui.
Out put flow will then be 0.841 x 3600=3,027.6 cui/min>>3,027.6/231=13.11 gpm
That is the theoretical flow, which will be reduced when internal leakage gets counted into the equation. Volumetric efficiency is not posted in the H&B pdf, can be expected to be between 85-95% with a 300SSU/57cSt viscosity oil and at operating pressure.
Since high flow is at a lower pressure, I would "guesstimate" eff to 95%, and actual high flow would then be about 13.11 x 0.95 = 12.5 gpm....
Not a big deal, but with wrong impression of real flow, it is easy to make a call for a bad pump....