Optimal Airflow Question

[Look]

I have a Coolermaster Hyper 212+ heatsink, using a push/pull dual fan set-up. Currently, I have 2x 120mm intake in the front, and 1x 120mm exhaust. The intake fans are rated @ 50.1CFM, and the exhaust fan is 90CFM. I have another 90CFM fan is the pull in the HSF setup.

The case is a Coolermaster Elite Elite NV-334-KWN1-GP: http://www.newegg.com/Product/Product.aspx?Item=N82E16811119199&cm_re=coolermaster_Elite-_-11-119-199-_-Product (The second intake fan is right under the 1st 5.25" drive bay, I only have one DVD drive installed)

My question is, would it be better to use the 90CFM fan as an intake and use the 50.1CFM fan as the pull, or should the 90CFM be either the push or pull on the heatsink setup?

Thanks for your time.

 

[delluser1]

The push/pull fans on your heatsink should be the same CFM.

 

[Look]

Alright, thanks. Looks like I should have done more looking before buying that 90 CFM fan. At max, it will be 13.2 CFM higher than the fan that is with the Hyper 212+ (90 CFM vs 76.8 CFM).

Is it true also that if the second fan is too close to the exhaust fan in the back of the case that it will actually cause more turbulence and be counterproductive?

 

[JDFan]

Alright, thanks. Looks like I should have done more looking before buying that 90 CFM fan. At max, it will be 13.2 CFM higher than the fan that is with the Hyper 212+ (90 CFM vs 76.8 CFM).

Is it true also that if the second fan is too close to the exhaust fan in the back of the case that it will actually cause more turbulence and be counterproductive?

The push\pull on the HSF should point toward the back of the case so that the rear exhaust will expel the hot air from the case after it is pulled through the heatsink in order to avoid that from happening ( if the HSF fans are pulling the airflow to the top of the case instead of the back or blowing it toward the front of the case instead of the back then yes it could cause disruptions in the airflow inside the case causing the hot air to recirculate inside the case instead of being expelled thus raising the internal case temps.)

 

[das_stig]

Always best to create negative pressure within case, i.e more air being exhausted than be taken in.

 

[jsc]

Alright, thanks. Looks like I should have done more looking before buying that 90 CFM fan. At max, it will be 13.2 CFM higher than the fan that is with the Hyper 212+ (90 CFM vs 76.8 CFM).
A 90 cfm fan at full speed is going to be really noisy.

Is it true also that if the second fan is too close to the exhaust fan in the back of the case that it will actually cause more turbulence and be counterproductive?

I kind of think so. I did some testing with my ThermalRight Ultra 120 Extreme two or three years ago with 2 fans in push pull in an Antec 900 case. The second fan didn't seem to help.

Of course, YMMV.