My own opinion is that it would have done quite well and would not have been out of place but it would also depend on what altitude it had to fight at. At low altitudes, it was pretty hot, but typical combat against bomber escorts was much higher in Europe and although its altitude performance was good by Japanese standards, it wasn't good by European standards.
(1560 HP @ 17,900 feet Military Rating)
Then again, if it was operated in Europe, it probably would have had better than the Japanese Navy 92 octane fuel and would not have needed water-methanol injection most of the time.
As for swapping engines, the whole concept of this aeroplane was to fit a very large diameter high powered bomber engine into a fighter.
The engine was very wide but not very deep, so I am guessing that to convert to a P&W R-2800 would require quite a bit of structural modification.
As for using the additional power, I do not believe this would have been a bit deal..............
..................With better fuel, perhaps the volume taken by this 120 liter tank could be used for additional fuel.
Comments and Thoughts?
Just so we are all on the same page fuel wise.
87 oct.......68.29 PN
91 oct...... 75.68 PN
92 oct...... 77.78 PN
95 oct.......84.85 PN
96 oct.......87.50 PN
100 oct......100 PN
Use of JM2 by Italians is problematic due to the Italian fuel situation.
Use of JM2 by the Germans is also problematic. Results on B4 fuel even with water/alcohol is not going to be good. Results with C3 fuel may be better?
Use of JM2 By Russians is probably still going to call for water/alcohol.
Use of JM2 by British/Americans
might be limited by the strength of the engine rather than fuel. Will the Kasei actually stand up to the pressures the allied fuel will allow?
Granted not everybody measured fuel the exact same way. I would also remind people that the Germans, Russians and Japanese never actually measured or rated the fuels for rich response. Japanese,
if getting their fuel from the Dutch east indies
may have had a bit better than 92 octane for rich response. Depends on aromatic content.
The Wright R-2600 is the closest western equivalent. it was 200-300lbs heavier depending on version which makes one wonder about the life of the Kasei at high power levels. The Wright may not have had a very good supercharger, or they didn't change it much on the 1900hp BB series?
As to propellers, they were sometimes matched to expected altitudes. The prop that works at sea level for take-off or sea level speed runs often doesn't work so well at higher altitudes (over 20,000ft?) depending on the power of the engine. The big props on the R-2800s were to transmit 1800hp at 15,500ft (no water injection and no RAM) or 1650hp at 22,500ft. The air at 22,500ft is roughly 80% as dense as the air at 16,000ft.
The R-2800 "B"s ran 2700rpm max so difference in reduction gear is minor.
Another problem is cooling on these radials, not so much in high speed level flight but when climbing. Please note the "C" series R-2800s required about 10% less cooling air
at the same power as the "B" series engines. Also note that the 1900hp Wright R-2600s used a massive increase in cylinder and head fin area compared to the 1700hp versions. You not only have to make the power, you have to survive making the power.
A Kasei given Allied 100/130 fuel might very well be able to make much higher power for a few moments, the question is for how long? And under what flight conditions? Flying straight and level or trying to climb at max climb rate? or running at military power (or WEP) while banked over and doing a hard turn at low speed? How long before temperature needle goes into the red zone?