I've done two calculations, see below:
DB 605A on late Bf 109G versions:
1.42 ata / 1044.5 mm Hg / 41.12 in Hg / + 5.97 lb./sq.in (PSI) boost
Merlin 63, 66 and 70 on Spitfire IX:
2.86 ata / 1350 mm Hg / 53.15 in Hg / + 18 lb./sq.in (PSI) boost
This is a fairly simple way of demonstrating Allied technical superiority. Of course, boost is not the only relevant factor. See this graph for the P-47's extraordinary high altitude performance, even at relatively low boost -
http://www.wwiiaircraftperformance.o...7m-n-speed.jpg. This takes the conversation back to the topic of next generation technology, namely turbosuperchargers.
Regards,
Paul