Temperature difference before and after turbo

Hallo, does someone knows how many Celsius degrees difference should be before and after compressor? I suppose it depends on outside air temperature (OAT). In case of OAT in example 10 Celsius degrees how is deltaT? And in case of OAT 30 Celsius degrees?

My standard flight values with 915iS are: 5000 rpm, 31 inch MAP. Fixed pitch propeller. Speed=88 knots (163 KPH)

By OAT 25 Celsius degrees and by level flight, Oil temperature is 105 Celsius degrees and water temperature is 110 Celsius degrees.

Thanks!