Hi
My latest radiator is from a 944 Porsche in all aluminium. I have used Audi 100/200 ones in past.
I've used Audi fans with the Audi fan housing which work pretty good.
On the 944 radiator that I'm using now I tried an unshrouded fan which wasn't very good. I'm now using twin 11 inch Spal fans which have an amazing amount of airflow. They came with a fan housing that I needed to trim to fit the 944 radiator.
You can tilt the radiator so that it sits lower and is supposed to make the radiator work more efficiently. You need to use a radiator as wide as possible and seal around the radiator so that all incoming air goes through it.
Cheers Steve
link to fans that I used
https://thermofans.com.au/collection...roducts/ef3580