Need Help With Duct

[NeoMoses]

I'm gonna be cutting a hole in the side of my case directly above my processor and putting a duct there. I have a couple of questions.

1. I'm running a CAK38 with the Delta38 on it. Should I:

a. leave the fan on the heatsink, and no fan directly at the inlet of the duct?

b. Take the Delta38 off the heatsink and mount it on the case, at the opening of the duct?

c. or should I have 2 fans, 1 at the opening of the duct, and leave my CAK38 on the heatsink?
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2. Is a 60 mm hole/duct going to be large enough, or should I cut an 80mm hole and taper the duct to the HSF?
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3. I've heard of people spreading the fins on the CAK38 and putting an 80mm fan on it. Does anyone know of a link to an article about this?

I'm thinking about spreading the fins slightly(to around 70mm), taking the Delta38 off the heatsink, and mounting it on the side of the case, where the duct hole is. Does this sound like a good idea?

[*JEREMY*]

There is really no sure answer,I have heard people get different results they liked with all the combinations you mentioned but I think most of it comes down to what your airflow in the case is like.Personally in my old case I got the best results from taking the fan off my hs and putting a 120mm fan in the back of my case and making a duct that went from it right to the top of the heatsink(sk6) and had it sucking the hot air off it but I also had good airflow coming into the case that was being pulled through the fins of the heatsink and then out the duct.Wheres nihili at he's the duct expert:p

[WarriorII]

I have tried what you're doing with little results. 92mm down to 60mm (delta 38 screamer)
By removing the "Duct", that alone seemed to help.
It also helps system temps. I use a side 92mm. Go for the 120mm. It will have better flow.

Keep Both fans in the system.
[Need a pic for this but here goes]
My HSF "clip" goes up/down (north/south)in the case. My HSF "fins" go East/West. From the side (east/west) I ducted a 92mm fan to pull air out the side of the HSF @ the bottom. That way the Main HSF is still in place and I have a 2nd fan pulling air out. Not to mention the Fan in the side of the case blowing "FreshAir" onto the main HSF.
:cool:
Hope this helps.

[Hoot]

I just put a rig together for my wife using my old Enlight 7237 mid-tower that used to house my "Hoot Chute". The HSF is the Millenium Glaciator and since there was a hole in the side right over the CPU, I put a 92x32mm fan on it, blowing down onto the CPU. On the front, there is a cutout for a 120mm fan with nothing in it, so resistance to airflow out of the case is minimal. The 92mm fan not only blows cool air into the HSF, but provides adequate throughcase ventilation such that the CPU is running at 30C idle and 35C Prime95 Torture. That setup would work for you with your CAK38. I'll assume you do not have a 120mm hole in the front of the case already, but rather the stock 80mm hole that most have. If you put an 80mm fan in it blowing out, it will accomodate the 92mm blowing in for adequate through-case ventilation. My wife's rig is running a 1.33Ghz Tbird at 1.45 Ghz.

73, Hoot

[NeoMoses]

thanks for the quick advice! I'm in the process of making a cardboard side for my case to do some testing with. I'll update you if anything important happens.
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Update: I've tried 2 things. Fan directly above processor with and without duct. It's an old 80mm fan. I'm not sure the CFM, but I think it's less than 38. Temps are about 2C higher with the duct than without. Later on I'll try removing the delta from the Heatsink and putting it on the case with the duct.