[Walter Atkinson]

Kyle:

The thoughts about adjusting MP for an intercooler are misplaced for the reason I cited... the exhaust backpressure is negating the increase in power from the lower temperature. Recommendations to adjust MP from the manufacturers are in error since they have neglected to take the exhaust backpressure into account in their calculations.

Your concerns about high temp across the turbo charger are not warranted. That is before the intercooler. The rise is based on the compression, not the altitude. If you do not have an intercooler, your concern is warranted.

There is as much confusion over intercoolers as any topic. None of the oft-cited reasons for having an intercooler hold any weight as compared to the increase in the detonation margin. The omission of the effect of exhaust backpressure on HP output is a serious omission and has led to many erroneous conclusions concerning the effects of an intercooler.

I would not want to operate a turbocharged engine without an intercooler since I have seen the test stand effects of not having one! The detonation margin is minimal in most non-intercooled turbocharged engines and all it takes is a slightly reduced FF at takeoff power to wipe away that margin away. An intercooled installation has a much wider safety margin.

The increased CHT at altitude is from poor cooling in the thinner air, not increased heat inside the cylinder. The same heat is produced at any given power at any altitude. It's how efficiently that heat is removed that alters the CHTs.