Hey guys!
I have wondered the same thing myself. The DB603 was the original engine for the FW-190D series. It was 300 pounds lighter than the BMW 801 series and developed as much Horsepower as the Jumo. When engine feasibility study was completed on the Dora the DB603 equipped Dora was 200 lbs lighter than the Jumo 213 Dora. I have to look up exactly why but it was lighter. I think the DB 603 equipped Dora did not have to have such a radical extension. The RLM simply told Tank, "NO", he couldn't have DB603 engines for the type.
It was used in the Do 335, Ta152C, Ta154H, and He 219. From what I know there was simply a shortage of these engines and they were allocated to other projects.
The FW-190C's High Altitude performance was not up to expectations. The Ta-152 was in the works and expected to be a leap in performance at the target altitudes over the FW-190C. Additionally the exhaust extensions on the FW-190C caused problems. In the end, with better stuff in the works, it was deemed a waste of time and effort to perfect.
DB 603
Technical Data:
Type: 12 cylinder inverted-vee
Bore: 162 mm (6.38 in)
Stroke: 180 mm (7.09 in)
Volume: 44.5 l (2715 cu in)
Weight: 920 kg (2030 lb)
Power (A): 1290 kW (1750 HP) at 2700 rpm
(G): 1395 kW (1900 HP) at 2700 rpm
(N): 2060 kW (2800 HP) at 3000 rpm
Continuous (A): 1190 kw (1620 HP) at 2700 rpm
(G): 1145 kW (1560 HP) at 2700 rpm
(N): 1420 kW (1930 HP) at 3000 rpm
Jumo 213A
Technical Data:
Type: 12 cylinder inverted-vee
Bore: 150 mm (5.90 in)
Stroke: 165 mm (6.50 in)
Volume: 34.97 l (2135 cu in)
Weight: 920 kg (2030 lb)
Power: 1280 kW (1740 HP) at 3000 rpm
Continuous: 880 kW (1200 HP)
Crumpp