Using an oversized fan

[SilentDoh!]

I have been wondering if you have something like the Corsair H50 CPU cooler and you wanted to get better performance out of the cooling system is it possible? (By better performance I am thinking cooling better) If it's possible could you do it by putting a higher RPM fan on the radiator or would you have to some how fit a physically bigger fan with some kind of funnel adapter to it? Like go from a 120mm fan to a 5" fan on your radiator.

 

[sweeper240]

Yes you can increase performance by either/both placing a larger fan near or in replacement of an existing fan (depending on the fans performance characteristics - CFM) or by increasing the speed of said fan or replacement fan big or small (again depending on the performance characteristics)

Larger is better
Faster is better

 

[SilentDoh!]

So is there ever a time where you would go with larger than faster to replace a given fan?

 

[paul-e-wog]

So is there ever a time where you would go with larger than faster to replace a given fan?

Some people choose to place larger fans on their cooling equipment because larger fans may offer identical or better cooling performance to smaller fans, at a much quieter noise level.

Some retailers sell funnel-type adapters for fitting larger fans into smaller fan hole sockets--you may be interested in this guy:
http://www.frozencpu.com/products/9...20mm_Fan_Adapter_-_Black_BP-FA140120-BK_.html

Like sweeper240 says, putting a fan on the cooler that has a higher rpm will give you better performance, and so will mounting a larger fan on that cooler.

 

[SilentDoh!]

Thanks for the link that is what I was wondering about. But since you both are saying the same thing I take it that a higher rpm fan is the same performance as changing to a bigger fan. There isn't a situation where changing to a bigger fan will give you better performance than going with a higher rpm fan.

 

[paul-e-wog]

... I take it that a higher rpm fan is the same performance as changing to a bigger fan. There isn't a situation where changing to a bigger fan will give you better performance than going with a higher rpm fan.

This is somewhat a gross simplification, but you might consider that airflow, and therefore cooling performance, is proportional to the product of the fan's fin area and the rpm of the blades. Noise is more a function of the rpm, motor design, and perhaps to a lesser extent, fin shape.

Thus, if we have an 80mm fan running at 1000rpm, we might wish to install an 80mm fan running at 2000 rpm to improve cooling performance of a heatsink. But, such a fan may provide less cooling performance than a 120mm fan running at 1600rpm. So, there are certainly situations where changing to a bigger fan will give you better performance than simply choosing a higher rpm fan.

[Don't trust my numbers to be accurate.]

In many situations, however, we may not have the option of installing a larger fan. Then, if we would like to improve cooling performance, we would install a higher rpm fan of the same size as the previously installed one.

Hope this makes sense.

 

[Mr. K6]

Bigger fans are not always better, especially on a radiator. Put very basically, your performance comes from how much air you can move over the fins per unit time. Increasing the fan size or shape doesn't necessarily change that (for example, if your larger fan has a proportionally bigger hub in the center, you might actually lose airflow). Increasing the RPM of a given style and size will obviously increase airflow over the fins. But most importantly, especially for dense fin arrays, is to use a thicker fan that can generate a better pressure (for example, a 120x38mm as opposed to the standard 120x25mm), as the pressure helps push the air through the fins much better.

 

[SilentDoh!]

Sweeper240 and paul-e-wog thank you for you input I appreciate. Mr.K6 I had noticed that some fans were thicker than others but really stop to think why they were or what benefits you get from it. I really have a much better understanding of cooling fan dynamics now thank you.