We are having record heat rite now in most parts of the country.
ALL cars suffer HP loss when its a blast furnace .Iv'e noticed it myself on my car and I have a huge stock dual pass intercooler due to my Harrop Supercharger being designed in Australia where triple digit temps are the norm.
Wait till the fall and it will wake back up....
No matter what you do rite now, when the ambient air is around 100* nothing will change.