Mismatched fans for push/pull?

The amount of air that makes it through a radiator isnt enough to do anything to another fan (push or pull) that I have been able to test, up to 2600 rpms fan. I can put my 2600 rpm fan on either side (push or pull) and it wont spin the other fan...though I can gently blow on the stopped fan and cause it to spin. I can monitor rpms on 800 rpm fan, and cant alter them with 2600 rpm fan opposite.

Feel the air that comes through radiator vs blowing air on your hand and you will see why.

Cant attest to 6000 rpm fan would do...but 2600 rpm on one side and 800 rpms on other, my only issue would be 800 rpm fan is probably just adding noise, but isnt hurting either fan. If you got a very thin rad and huge spaces in between fins...but on typical rad dont think it matters.

I could see mix-matched fans could also cause higher noise levels possibly. Maybe the turbulence from one to another?

Say the second fan is the weaker one, wouldn't it just add more resistance for the first fan to work with while having the radiator to deal with? One would think having the same fans in push and pull @ the same speed would sync them together perfectly. Metaphorically speaking, like 2 guys on a row boat. Both of them sync'd will move the boat faster as opposed to one guy doing most of the work.

Dang, reading this thread is like being back in school. Well, at least when I was in school.