What is my Fan RPM?(Koolance fans)

I have the PC2-901BW (http://www.koolance.com/products/product.html?code=CCS-A08&category_id=2)

I was wondering what CFM my fans were that cool the radiator..because I want to get better ones, but I havn't turned it on with the water yet..

but I do'nt want to buy three tornados..they're too expensive..

READ this before you go changing the fans. WARRANTY LINK
Says if you mess with the fans it voids the warranty.
THE FANMAN

thanks, but I'm still wondering..

I'll just ADD fans then..lol