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Old 04-19-2021, 05:39 PM   #144 (permalink)
JulianEdgar
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Quote:
Originally Posted by Autobahnschleicher View Post
Yes and no.
There is a correlation between cooling air demand and cooling drag as well as a corellation between power and cooling demand.
It's not perfectly proportional and depends on the engine type a lot, but more powerfull engines of a given type have a tendency of requiring more cooling, resulting in a higher cooling air demand, wich causes more drag.
In addition to that a lower deltaT means more cooling air is required for a given thermal load.
This is theoretically correct but it is incorrect in practice.

There is no correlation between engine power and cooling drag (as a proportion of overall Cd) for ICE cars for example.

The ICE car that I have data on with the second-lowest cooling drag proportion is also a very powerful car; whereas the data I have on the car with the lowest cooling drag proportion is a very low power car.

So more depends on car design than engine power.

(This is also why people saying that my use of the Tesla Model S and Taycan for high proportional cooling drag in BEVs is no good, because they're powerful cars, are missing a key point.)