Will a fan adapter lower my CFM?

[EnFoRcEr!!]

Im curious about this because my dad needs a 60mm for the back of his case. The only problem is you cant get one with good output without the noise-level to go with it. If he got a panaflow 80mm, and used an 80mm-->60mm fan adapter with it, what kind of a percentage would he be looking at for CFM reduction?

[tom61]

I asked this in the cooling forum, and the answer was yes, it lowers the output significantly.

[df12]

As an alternative you might try mod'ing a Blower style fan to fit. They usually have decent CFMs and low dBs...

Just a thought.

[nst6563]

it also depends on the depth of the adapter. If the adapter is deeper, then it will have a slight funnel effect and overall increase the static pressure slightly. But that really doesn't matter when it's exhaust.

It would have better results on a hsf...but the adapter would have to be at least a couple inches high. Think of the K&N Cold air intake (I think they call them Filter Chargers)...the large end with a large air filter "funnels" down to a smaller opening to the throttle body of the engine.

[Ice Czar]

http://www.nmbtc.com/pdf/forum/engineering_101.pdf