It seems to me that one of the blower motors I engine dyno tested made 50 HP less at 190 F MAT(manifold air inlet temps below the blower) compared to 130F MAT, maybe not so much, maybe more Hot air expands a bunch I do remember switching pulleys and going from CA pump swill to 112 octane ras gas and going from 12% under dirve which made 7.0 lbs of boost at 7300 RPM made 924 HP, reversing the pulleys ended up making it have 13% O.D. and 12 lbs of boost at 6500 RPM with a lot hotter MAIT which cause detonation at 6500 RPM making 1027 HP with 25 degrees total timing. The pull on pump gas with less O.D. and boost pressure liked 33 degrees total timing, we treid from 27 to 36 degrees in two degree increments on the pump swill Looking back at those test I should have started the race gas pulls with 20 degrees total timiing, not 25 We treid 28 and it got worse in a big hurry The owner was way happy and it was late in the afternoon so we stopped while the motor still ran On a blower motor I would bet that back pressure is a big No No
One of my old N/A bracket cars picked .9 ET and 9 MPH going from a 2.5 inch exhaust system with the old Corvair turbo type mufflers with a short side exhaust to open headers with no other changes My pump gas Duster with a three inch system picked up .02 ET and .2MPH in the eight mile by removing the exhaust system from the headers flanges back That gain was probally from the weight loss and not back pressure
I know a west coast blown alcholol racer that sees 400+F MAIT at 50 lbs of boost on his deal