One of my friends here runs Chevrolet’s stuff ( I know, but I like him anyway ) and he runs fans and pump until he stages then shuts everything off.
He works his system to make sure he stages at 165 degrees.

The conversation came up as I mentioned I used to use an alternator cut out switch so alternator was “ no load “ when racing .
He does similar with a mater switch that cuts off pump/ fan and alternator when he stages.
Kicks everything back in at end of run.

I cannot find anything in rule book to prohibit this.
Thus my question on the radiator/ cooling , thinking an OEM unit might be lighter and take off temps faster that the aluminum/ after market.

Does anyone here do similar with temps/ cutting off pump/ fan for your pass?
Secondly , what temps do you like at staging ?

Thirdly - fan shroud : ones I have looked at for puller fans completely close off back side of radiator , wondering how much air dam/ drag issue that creates ?
It would seem that letting air flow through radiator on a pass would be less drag in the car.

Thoughts/ experiences?
We will go ahead with a champion , 3 core seems about right .
Fan/ shroud design I’m uncertain on.