Clothes dryer duct vent.

My friend has an eMachine with a plastic duct that clips over the HS fan to take the hot air off the CPU out the back vent. Way back when, I had a P3 Dell Optiplex GX110 that had virtually the same set up pulling the air through the HS then out the duct rather than blowing air on the HS. Neither computer had/has a case vent fan. In theory I think that's better than blowing through the HS recirculating the hot air around in the case. I assume the main heat generator inside the case is the CPU HS.
Granted, the PS produces significant heat but it's dedicated fan takes the hot air out the back and doesn't "recirculate" it inside the case like the HS fan.

In another forum a guy said you could achieve the same thing as the eMachine & Dell by making a home made duct out of 3 or 4" clothes dryer duct and secure it to the HS fan with twist ties, then twist tie it to the back vent to blow the hot air out. I would use strips of duct tape to tighly seal the ducting to the fan and vent.

I am aware the most efficent fan configuration is blowing into the HS rather than pulling through. Thinking it through, I wonder if maybe the duct vent is a sort of trade off and causes the air inside the case to be much cooler.
Hmmm . . . . veddy interes-tink . . .

In another thread we discussed case cooling so yesterday I ran two "inside the case" temp tests using an encased mercury pool thermometer. First test with one 30CFM exaust fan and one 30CFM intake. Thermometer left in place for two hours situated at the top of the case half way between the DVD drive and PS.
Ambient temp 78F. First test I saw 87F. Next test I disconnected the intake fan and saw 90F. CPU temp remained fairly constant 38-40C, both tests at idle.

For some reason eMachine seems to have taken a lesson from Dell on the duct thing and I'd like to know why. The Optiplex was probably five - six years old, so Dell used the vent back then.

Sounds like a fun project and wondering if any of you have ever done anything similar. Think I'll boogie on over to Lowe's today and get a piece of duct and give it a shot. The pool thermometer is somewhat crude but gives a pretty good idea of exactly what the temps are inside the case and the cause and effect of different case cooling fan configurations. When I have some actual-factual temp readings I'll come back and post the results and meantime please share your thoughts.

Athalon 2100+ downgrade T'bred 2600 B core OC'd 2166MHz, EverCool CUD-725 cooler w/ Arctic Silver II, Soltek SL-75MRN-L, 512Mb Crucial RAM, DVD, CDRW, Internal ZIP, DynaPower Atlas case.

Have a superb week end and be kind one to another.
OldBird

Ye that does sound similar. I had an old Gateway Cel. 333 and it had a partial duct which used the PS to draw air over the heatsink. It ran just fine. It was my first folding machine. MY current machine is alot faster though. I prefer no ducts because when you have all that air circulating it cools the northbridge, RAM, video card, hard drive, etc..

Thank You,
Daniel

Internal cooling.

I understand what you're saying. However, if you have an intake fan it circulates cooler ambient air around everything where as the CPU HS fan recirculates air already heated.

My MB displays CPU and MB temps so I can keep an eye on both and see what temp changes take place.. Might not get to it today, just got some honey-do assignments from she-who-must-be-obeyed . . . . :-(

It works

i read the same thing in a PC mag. a guy in the states had the same sort of set up. after reading the artical i tried it, my PC ran 5 degrees cooler. IT'S A GOOD SYSTERM

Thanks for the info.

Thanks for the encouraging words, you got me interested.

The guy that bought out eMachine ain't no dummy and I figured he wuz on to sumpthin' because he saw fit to follow Dell's suit.

Laugh if you want, since being bought out for pennies on the dollar eMachine came a long way in the last two - three years and now makes a pur-tee good entry level 'puter at an affordable price for the masses.

OldBird

Yeah 90% of all PII, and some early P3 based chips used a passive sink with partial "channels" leading to the standard slow 80mm exhaust.

The problem lies in that you're going to have to seriously step it up in fan movement to get it to work now.

Keep in mind PII/slot PIII's would be low heat today, and also had MASSIVE heatsink size because they had to cool the cache also.

IMHO I don't see how anyone would a modern chip could do this effectively.

Just do a duct to bring fresh air to the CPU. You can use dryer vent.

*If you want to increase the flow you can mash down the ridges and smooth them out with the foil tape they use for heating, a/c duct joining.

Not only that it's nice and shiny and you can wire a hyper blue LED to the fan like I did and get an ultra cool effect! Adjustable to fan speed if you use a rheo too!

Yeah honeycutt, I have sevrial friends that wound up buying E's instead of letting me build them a better one.

I got'cha Toys. Yeah, eMachine has come a long way and I recall reading in 2001 eMachine was second in customer satisfaction ratings. HP number one, Compaq second. I read the whole story of the guy bought them out for pennies on the dollar and his philosophy is not in stockpiling computers but ordering them as they are sold. Therefore you get the latest technology and not one that has been sitting on a warehouse shelf for a year.

Some years back I bought a compaq from Staples and brought it home and was poking around in Task Scheduler and found the first task performed was over a year ago which told me that was the date of manufacture. I made a phone call to my computer Guru who confirmed my suspicions. Packed that puppy up and took it back and told Staples if I paid for new I wanted new. They said they couldn't take them and hook them up to see how old they were, so they refunded my money.

I don't know about XP, but in Win98 or ME do this:
Run a search for scheduled tasks, or task(s). Open the folder Scheduled Tasks. Click Advanced - View Log and you will see the first, or last, time an OS was installed. I run ME and checked and last time I formatted this new HDD was 6-13 and there it was as the first entry in the log.

Gotta' run for now. This sure is a fun place, good group to hang with, and knowledgable to! OldBird

Toysrme said:

Yeah 90% of all PII, and some early P3 based chips used a passive sink with partial "channels" leading to the standard slow 80mm exhaust.

The problem lies in that you're going to have to seriously step it up in fan movement to get it to work now.

Keep in mind PII/slot PIII's would be low heat today, and also had MASSIVE heatsink size because they had to cool the cache also.

IMHO I don't see how anyone would a modern chip could do this effectively.

Just do a duct to bring fresh air to the CPU. You can use dryer vent.

*If you want to increase the flow you can mash down the ridges and smooth them out with the foil tape they use for heating, a/c duct joining.

Not only that it's nice and shiny and you can wire a hyper blue LED to the fan like I did and get an ultra cool effect! Adjustable to fan speed if you use a rheo too!

Click to expand...

Toysrme, are you sure you are right? My friend has a dell, it is dead quiet,I believe it uses a duct the way he desribed, it is a p4 2.4ghz, and he hasnt had any heat problems with it. But it might be a duct that gets air from the outside, i'm just not sure, i'll have to look next time.

Maybe so maybe not. I know a good friends Gateway 1.6g PIV would random heat lock and it had a 60mm fan sucking air off the heatsink, pushing it down the green duct to an exhaust 80mm.

The ambient was fair to high, but you'd think OEM solutions would be the last word in quiet stock cooling

Anyways, that's why I'm basing my opinion on, maybe I'm wrong maybe not, try it and see!

IMHO Ducting cold air too the sink will always be better than hot air out. Keep in mind you get a nice warm flow over the hot caps and other things on the motherboard with a heatsink too.

schismspeak

I don't know of a fresh air duct on OEM computers yet, it'll problably never happen :\ Noise and OSHA laws heh... Fans directly on the outside of the case, or with access to it don't get any sound muffling.

That's one thing most people I think don't get. It's not JUST that OEM solutions ar cheap. Unlike us, they have to work well under strict OSHA laws.

What is OSHA? Also I think he may have a fan on the bottom of his side panel, but again i'm just not sure.

edit: I'll ask him all this when he is on msn messenger this evening.

Occupational Saftey & Health Administraton.

That's the part of the government that all employers have to deal with that's *not* taxes...

They keep things safe.

They also have ambient noise laws for computers in offices.
Sticking a fan on a case panel is noisy. I've never seen a big name do it.

"Toysrme, are you sure you are right? My friend has a dell, it is dead quiet,I believe it uses a duct the way he desribed, it is a p4 2.4ghz, and he hasnt had any heat problems with it. But it might be a duct that gets air from the outside, i'm just not sure, i'll have to look next time."
I know, I have a 2.4GHz Pentium 4 Dell, too.

I have a duct that goes straight in through my side panel to my cpu. It's a 4" piece of pvc pipe. My cpu hsf pulls air in through it. It dropped my temps by about 6C.
I tried it the other way, with the fan on my slk-800 turned around to blow air out of my case through the duct. My temps rose 10C.
The slk-800 is desinged to have air blown on to it. A heatsink that is designed to have air sucked away from it would probably work well with a duct that exhausts the hot air from the cpu out of the case.

I did the clothes dryer vent thing!! Works great and looks very industrial! Plus its really neat, you can relly feel the air getting drawn in.

H m m m m . . . .

I keep hearing, use the duct to bring cool air IN to the CPU, not blow it out. Sounds logical because generally speaking the best fan configuration is blowing on the HS, not pulling it through. I picked up some 4" aluminum duct so I'm ready to go.

Slept on this and thought it through and like to share my thoughts:
On this case I have one back vent and one bottom-front vent and if I attach the duct to the back vent to take the air in I lose my exaust fan. I could mount the exaust fan outside the case blowing IN the duct and "ram" the air in the duct to the HS fan. Only other way to retain the exaust fan would be run the duct from the front intake to the HS fan, but that would take maybe a foot and a half to two feet of duct.

Another consideration is the back vent is right below the PSU exaust fan and the duct intake fan would probably pick up some of the hot air from the PSU exaust fan. I'd have to fabricate some sort of cardboard deflector to deflect the PSU exaust air up instead of straight out the back. I can handle that.

I'll have to be careful not to let the aluminum duct touch the MB and short something out. Using the above configuration the only exaust fan I'll have is the 30CFM PSU fan. Lot's to think about here and I won't know until I try it . . .

Lemme' get a few cups under my belt, get my brain in gear and my old eyes open and see where I want to go with this.

Thanks for sharing all the good ideas. I'm an old Hippie and this brings to mind the old Beatles song, "I get by with a little help from my friends . . . . " OldBird

PS Way back when, I saw Jimi Hendrix in concert, absolutely awesome and still got that "Purple Haze All In My Brain."
My oh my, let me tell you good folks, them WUZ the days.
;-}

Ok, i just talked with my friend, his dell has a duct out the back, the fan is on the HS blowing away, and 2 psu fans blowing out, so it has no fresh air except the lille vents in the bottom, he has never had any heat problems and it is a p4 2.4. his friend has the same processor on a little bit older dell and leaves it on for months at a time and has never had problems with it either, so i guess it works. Except I dont know how well it would work in a 28C plus room.

star882, How hot does your processor run on your dell? And what is the room temp?

"star882, How hot does your processor run on your dell?"
The heatsink is only warm to the touch.

I have a Britney HSF on an old 800MHz P3(in a Dell NLX mobo!), and the HSF is only slightly above room temperature.
The Britney HSF is ducted(Britney CPUs give off lots of heat(~130w)).
Idea: Stick a Britney HSF on a Pentium 4, and then see how far you can overclock it(even with the 130w of a Britney CPU, a Britney HSF stays cool)!

I would like to know what the mobo reports, just cause it is "warm to the touch" doesnt mean it is at a low temperature, heck, when my amd is at 50C the heatsink is only warm to the touch! And you keep going on but the britney HSF being on that p3 and keeping it a little over ambient, well you if you put an slk800-900 with a vantec tornado fan(sunon tornado) it would keep it pretty near ambient too, especially if it isnt in a case, which I believe you said in another post that it wasnt in one.

Also when you say warm to the touch, is that under load or idle? I'd still like to know what a program says for reference.

"I would like to know what the mobo reports, just cause it is "warm to the touch" doesnt mean it is at a low temperature, heck, when my amd is at 50C the heatsink is only warm to the touch! And you keep going on but the britney HSF being on that p3 and keeping it a little over ambient, well you if you put an slk800-900 with a vantec tornado fan(sunon tornado) it would keep it pretty near ambient too, especially if it isnt in a case, which I believe you said in another post that it wasnt in one.

Also when you say warm to the touch, is that under load or idle? I'd still like to know what a program says for reference."
On both systems, it's under load,
As for trying to measure the temperature with software, I can't get MBM5 to work(not even sure if Dell mobos support MBM5).
I don't know what a SLK-800/900 looks like, but the fan on the Britney HSF is a Sunon.