Boost Pressure Temperature Fluctuations

[Cueyo]

Couldn't find a thread on here exactly related to boost pressure and temps (a few comments here and there), but I was curious about the actual correlation between our air intake temperature and boost generated by the turbo.

I know on geneal, as temperatures drop, the boost needed to achieve the torque target set by the ECU is lowered (denser air, etc). What I'm curious about in particular is the amount average boost pressure increase/decrease as temperature goes up/down. Is there some kind of formula to calculate this for our cars?

I ask primarily because during the summer when the days would be 90F, I would see anywhere between 24-26lbs of boost on the boost gauge in 3rd gear. That would happen when the intake air temps were pretty high (so like 100-110). Now that temperature has dropped - was 55F this morning, my boost peaks on 3rd gear at 21-22 lbs.

As a sidenote, was also curious about boost decreases as engine rpm heads to redline, I'll hit peak boost at around 4000rpm, then it'll slowly go down to 19lbs. Is that normal?

I live up in the northeast, so I'm curious what other northeastern folk see as the weather gets colder throughout the year. This is my first turbocharged car so I wanna make sure something isn't breaking haha.

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[Higgs Boson]

modern ECMs are torque based meaning the fuel and airflow tables are calibrated and then a torque model is created based on airflow, spark, and fuel and limiters are put in place so that boost, spark, throttle, fuel mixture, and so on can be adjusted in real time to follow the model.

when you have cooler weather you see less boost because cooler air makes more torque and in order to run inside the model the torque needs to be limited, typically in a slow way by limiting throttle or making less boost. ECM can use spark for fast applications like idle control, rev limiting, etc where an airflow adjustment takes too long.