New direction for case air flow

[Snafu]

So your computer is going to suck, eh? :

YOU will have to mount the HSF backwards so that it sucks air away from the heat sink and blows it through the duct work to the side exhaust. Should work okay althugh it is debatable if blowing or sucking air off the cpu heat sink is best.

Definitely worth a go .

FYI - I think it was Joeman who mounted a second fan close to the cpu fan and was able to get it to spin faster than rated. It was a neat trick. Because of this I wonder if a second 120mm fan at the end of the duct would help draw more air through the cpu heat sink .

[Ice]

So your computer is going to suck, eh? :

Now, that's just uncalled for, Snafu!

[Shayd]

Well mine was gonna blow chunks ...er...air, it wasn't gonna SUX!

Dangit, now gonna have to get that other 120 mm fan anyways to test it out!!

Actually I was thinking of how to create this duct. I was just gonna have a straight shot out originally as sorta shown here:

___
] [ - duct
'~' - fan
--- - HS


Then thought that if I created a funnel (fan width at bottom/wider at outlet I'd get a better venturi effect and nice thing is no eddies blowing/sucking the heated air around

___
\ /
'~'
---

What do you think?

[Snafu]

Okay I'm . I must admit that mine blows .

Not sure if you will benefit from any venturii effect. I'm no physicist but I think it's usually after the venturii that you get cooler air due to expansion but this depends on how much the air gets compressed by the venturii and expands after the venturii. Not sure if 120mm fans can push the air that high but then again maybe there is some effect - not sure.

They sell duct kits so you can have the cpu heat sink either suck in cool air directly from the outside or blow hot air from the cpu out - depending on which way you have the fan set-up (i.e., to blow or suck .

[Snafu]

Well I installed the thermisitor-less SilenX fans (probe removed) in the front and rear case fans. While I was at it I added some Vantec Stealth fans in the side and the top. Running all fans at low speeds using the Hardcano controller (~half speed) and 2F@H resulted in temps that were:
CPU: 49C, MB: 36C, RT: 18C, CPU fan speed: 2850rpm (RAM fan speed ~5000)

Definitely drops the temps with all fans at LO speed. However, it is not as quiet as I thought . In fact it is nearly as loud when using the thermaltake fans alone at HI speed .

The reason is not the SilenX fans themselves. It is simply because once I removed the thermal probe these fans thinks its in Hades and really crank up. No more "SilenX". However, they definitely move air at the Lo setting (approx half of full speed) and are down right nasty at full speed - think hairdryer . I think I will have to solder the thermal probes back onto the fans to drop thier speed to something more respectable and less annoying.

I did a quick test running the front/rear fans on the ear-splitting HI setting (leaving the room for half an hour). The HI ear-splitting setting only resulted in a 1C drop in CPU and MB temp. Air speed must be exceeding some point in efficiency to strip away more heat.

One thought came to mind. The probe acts like a resistor that varies with temp. If I add a resistor of the right ohms it will mimic a warm temp (depending on the resistors rating). At RT (18C) the resistance across the probe is 11.3 kOhms. At ~80-90C (cup of hot water from the kettle) the resistance drops to 2.2 kOhms. In nice warm water (~40-50C a guess) the resistance is 4.8 kOhms. I am thinking of adding a 5 kOhm resistor to mimic 40-50C. At full throttle the fans will run on HI as if the case temps were 40-50C (still quieter than without the probe). Using the fan controller I can adjust the fan speed between HI and LO depending on need (fans at the LO setting spin about half full speed).

Any thoughts .

[RotorHead]

Snafu, instead of putting a fixed resister put a variable one on there, that way you can set the fan speed to optimize noise and airflow.

[Snafu]

Thanks bud. I tried to find one at the local Radio Shack but they did not carry anything small enough - they are really becoming crappy in electronic supplies up here and are more focused on gizmos/toys than anything truly useful to those who like to tinker with circuits (I'll get off my soapbox now).

I did pick up a "variety" pack of resistors from 10 Ohm to 1m Ohm for a couple of bucks. I will try bench testing a couple but it challenging when you do not have a PSU on teh bench (hmmm, maybe I can use this as an excuse to pick a new PSU ).

P.S. my wife heard the fans running full tilt. Here first reaction was with bugged eyes "I thought you were going to make it quieter? That don't sound quieter!" .

[Killer Munkey]

lol snafu


give it a go with those variable resistors and see what you can get. but while the topic of ducts was brought up, wouldn't a really effient way of cooling the cpu be to duct cool air from a 120mm or what not right to the cpu fan?

[Snafu]

Well after a bit of testing I stuck with a 4.7kOhm resistor and modded the front fans (could not get a variable resistor small enough).

At low speed (7.4v) you cannot hear the fans at all but they move a fair bit of air. At high speed (11.9v) they do make some noise but no where hear what they were like and they move even more air.

I would prefer if my case had 120mm fans all around and my next case will have this unless I am running with water by then : lol: .

I agree that a duct directly to the cpu from the outside would be the best for teh cpud (maybe not so much for the rest). Actually I think the best solution is to have direct independent cooling for each component that generates heat or at least try to isolate each heat generating component to itself (ex. having the psu pull air from the outside rather than from the case and exhaust it outside).

I want to add a duct for the cpu but I have not seen anything that I like so far (I like something solid like clear plastic rather than something flexible). I would like to try the air flow set-up mentioned by Thugsrook. Looks like a good solution and a duct over the cpu should help.

Cheers.

[Snafu]

PS. Temps over night with the new fans were:

CPU: 47C, MB-35C, RT: 16-18C, CPU fan: 2600rpm.

They seem to have dropped the temps a small bit but I do not expect the temps to drop any more once the rear vents/fans modded as well (I think I hit a saturation point).

Once the mods are finished I plan to try Thugsrook suggestion and if I can find the ductwork I will try ducting cool air directly to the cpu.

[Shayd]

Woo hoo! Just got my lian 65 case in.

Mod time!

Other parts must be close behind as well. Since this is my 'virgin' run I'm planning on documenting my 'experiance'. This should give some of you a good

[Snafu]

Get out the sawzall, torches and grinders. Its play time !!!

All kidding aside, now is a very good time to plan out what you want to do with this case. For example, ever thought about painting the insides - if you want some "show". Actually it is a good time for any dremel work such as opening up vents to help the airflow, etc.

Let's see some pics of the operations.

[Shayd]

Hey guys,

As I posted in another thread, I got all my parts in and have started playing with my new toys

Anyways, I thought that before I dumped all the stuff in the case (still need to determine how I'm gonna mod it) I thought I'd take and set up up on the bench and do some tests that way.

Now, I got the XP-120 by Thermaltake, holey cow batman! Its even bigger in real life the thing is huge covering a good 6th of the mobo. Anyways, first run I thought I'd try what one of the other reviewers did, and not put a fan on it for just setting up the bios and checking the hardware moniter. Whoa, I touched the HS after only about 2min of running and had to break out the IR temp probe cause it was hot, 135 degrees hot. Roh oh, turned it off and dug out a panflo 120 I got. Tucked that puppy on and restarted. Temp dropped down to the low 90's. much better as its low 80's RT.

I placed the fan on so that it drew the air up thru the HS and away from the mobo. Loaded up memtest86+ and started it cranking away. Checked temps on the NB and it was a roaring 125. cpu was running avg around 100. Ok, what has this got to do with cooling? Well, I thought sucking was better then blowing thinking that pulling the hot air away was better. Now this is outside the case so it might be different when everything is all sealed up, but I flipped the fan so it was blowing air down thru the cpu HS. It turns out that the way the 120mm fan sits on the HS it has a sliver on each side that only hits the outer plate of the HS on eash side, so in essence is blowing cool air down and across the power caps on one side, and the NB on the other. Turns out the NB temperature dropped 10 degrees, and the temp on the cpu remained about the same, High 90's at the moment.

Now get this. I'm clueless on the OCing finesing, but wanted to see what my new CPU could do. Those temperatures I gave you just now? Those are running the OCZ memory at 2-2-2-5, and...are you ready!! FSB at 250!!!!! Holey cow, this 3.0c is pulling 3.75 all stock and on AIR! Three passes on Memtest86+ and still cruising. I know that isn't a good burnin, but I think I'm gonna be happy with this on if I can keep from smoking it

Time to see if I can bump it up some more Rock ON

[Snafu]

Cool Dude. Looks like you have a keeper! Congrats (I'm jealous ).

JJMan would be interested to hear about the temps without the fan on the cooler. He was noticing that the ram temp also dropped with the fan on the cooler. Benefits all around with this cooler. Cool.

[Shayd]

That XP-120 is Great! Running 2 fold programs at 250 fsb with temps running at 42c. Had to bump the Vcore up one step as folding would lock computer, at 1.57 now I think and appears stable. We'll see as I'll run it the next day or so to test before bumping up some more.

Scott