Molex Fan Modd

So.. I has looking at my case and noticed I have like 5 molex powered fans..

I was wondering: What if y got something like the NZXT GRID to controll fan speed? But I don't have PWM fans!! All I have is molex..

But then, Can I cut the molex header and use 3-pin headers instead?? Then I'd plug them all to the Grid and voilà


(There are only two wires coming from the molex header that power the fan... Just in case)

Am I missing something here??   I just want to know if it would mess with the fan or not..


Thanks a lot! 

yes, black, red.

But speed would be fixed? Or can I switch wires somehow to do that?

Don't they make adapters to do this?

That's exactly what i'm asking... But a big molex plug for just two wires just doesn't feel right for me. That's why I want to change it to a 3 pin connector