What they have probably done, is reduce the engine compression ratio without turbocharging so that, at sea level, it produces the same power with turbocharging as the normally aspirated version produces without. The advantage of this, is that the turbocharged engine will then be able to continue producing the same power up to high altitide by simply maintaining the boost pressure, wheres the normally aspirated engine would loose approx 1" of manifold pressure with every 1000' gained.
So. They will both develop the same power on take off at sea level, but wheres the normally aspirated engine will loose power as altitude is gained, the turbocharged version will maintain it's power. This not only enables climb perfomance to be maintained to a much higher altitude, but also improves high density altitude takeoffs by maintaining the engine's rated power at high density altitudes.
MJ
