First, it absolutely will not be worse to have a set of pulling fans on no matter what they are. The air flow rate a fan generates through a radiator is so much lower than it can produce with no resistance that even if the fans on the pulling side are running at a considerably lower RPM they will still contribute to increasing the airflow through the rad.
Its very much like using different pumps together. It works totally fine with different types and different speeds (within reason).
In fact using different model fans on each side of the rad can work better than using identical ones. It can avoid resonance and vibration tuning under some circumstances and lower noise.
Some fans work great in push and terrible in pull. The NB Eloop are the best example. I have combined Eloops pushing with Vardars pulling and its quieter than using one type alone.
One idea that people come up with because it can seem logical is to use static pressure focused fan on push and airflow optimised on the pull side with the thought that the push has to overcome the resistance while the pull side just has to move the air away as fast as possible. Of course in reality the pull side has to create static pressure just like the push side in order to create a vacuum/low pressure zone that increases overall airflow rate. Static pressure works in both directions.
Last edited by Ashcroft; 04-23-2018 at 06:43 AM.