Not trying to bust anyone's buns on this, but I spent my life in flow developement of air and liquids, I think removing those turning vanes would not be a good Idea, they are there for a reason. They actually increase the flow through the elbow by making it more laminar. Better off leaving them there.
This true airfoil contour reduces pressure loss to the lowest attainable level
Eliminates breakaway of flow from surface on suction side
Smoothly-rounded entry nose with extended trailing edge, no collection of dirt or debris
Provides velocity distribution of greatest possible uniformity
Maintains a consistently high-degree of deflection accuracy.
Derf/Fred