Router temperatures

[Jerom7]

I know you're talking about AC86U but if it can help : I got a 6°C drop on CPU just placing my AC88U vertically (LAN ports on top) instead of horizontally!! Greater than expected... (Now 63°C)
(Vents and internal radiators position facilitate the hot air evacuation this way it seems!) Cheerz' & keep cool ✌

 

[Matthew Patrick]

Does anyone know how much of a difference in temps and noise to expect, using the same fan to suck air OUT vs. blow air IN?
TIA

Someone tested in terms of temps. And push in configuration works better in terms of temperature than pull out configuration

 

[Kees17760]

Someone tested in terms of temps. And push in configuration works better in terms of temperature than pull out configuration

Thanks for your reply, but it's not much of an answer to my question.

 

[Matthew Patrick]

Thanks for your reply, but it's not much of an answer to my question.

Oh. Well as you know for temps it's better to do push in. And in terms of noise it might be the same tbh. But idk

 

[Kees17760]

Oh. Well as you know for temps it's better to do push in. And in terms of noise it might be the same tbh. But idk

Why would it be better to push in? All computer stuff i owned sucked air out of the casing.
Imo it's better to go with the flow and since hot air rises, it makes more sense to suck it out with a fan placed at or near the top or vice versa blow in at the bottom.

 

[Wade Coxon]

Why would it be better to push in? All computer stuff i owned sucked air out of the casing

Most computers with decent airflow have both in and out.
It would mostly depend on the internal volume of the device. The larger it is on the inside, the more likely that a pull configuration will be better though.

 

[MvW]

Why would it be better to push in air? All computer stuff i owned sucked air out of the casing

I can't answer your question but I can confirm that I bought two double fan kits for RT-AC68U, RT-AC86U etc on Amazon.nl and they're both blowing air in, pushing heat out through the (remaining) vent holes. There must be a reason for it, but I can't tell what the advantage is of blowing air in. The only thing I can think of it, when you reference to pc equipment, that our routers have vent openings at the back and on top, depending on the model and a laptop or pc has far less 'openings' to create airflow and they're built to be actively cooled, which out routers are not.

 

[Matthew Patrick]

Why would it be better to push in? All computer stuff i owned sucked air out of the casing.
Imo it's better to go with the flow and since hot air rises, it makes more sense to suck out when the fan is placed at or near the top or vice versa blow in at the bottom.

Probably because of vent holes and internal layout. But yeah. Push in method seems to be better. That's why I'm buying a fan with internal filter. Not that fine of a filter but enough I think..

 

[E3000]

Probably because of vent holes and internal layout. But yeah. Push in method seems to be better. That's why I'm buying a fan with internal filter. Not that fine of a filter but enough I think..

Filter is a good idea! Blowing cool air onto a heatsink will always give better results as that is literally how a heatsink works!

 

[heysoundude]

Does anyone know how much of a difference in temps and noise to expect, using the same fan to suck air OUT vs. blow air IN?
TIA

no, I don't think anyone has compared what you're asking for.
what I'm taking away from this protracted discussion is that for best heat reduction, you have to flow cool air in to displace hot air. natural convection works well enough, but pushing air in the back seems best (so far), but what might be better is pushing some cool air in and sucking some hot air out
I would put an exhaust fan above the top vents of the router between the antennae blowing up rather than on the back trying to pull air out that way...it may encourage hot air out the top and cool air in the back. just eyeballing it, you might be able to fit a 50mm fan in each of the 2 spots. add a 120mm on the back and...hmmm...
Anyone?

 

[Tech9]

I made a small shopping

Hey Marco, 55 euro is way too much for this project! The fan doesn't have to be attached to the router. Buy one 120mm ball bearing fan and one 5V-12V/1A adjustable voltage power adapter. Place the fan behind the router and run it on whatever voltage gives you acceptable noise/cooling balance.

 

[gattaca]

Someone tested in terms of temps. And push in configuration works better in terms of temperature than pull out configuration

Yes, in every test I ran, blowing INTO the rear of the router delivered lower temps than pulling air through the router with the fan strapped on the rear of the unit.

See -> https://www.snbforums.com/threads/asus-rt-ac88u-to-hot.58405/page-2#post-518345
See -> https://www.snbforums.com/threads/asus-rt-ac88u-to-hot.58405/page-3#post-665525

I have I summarized a rough shopping list based on my findings in the post above # 665525. That's what I'm using on my 2 x AC86U and 1 x AX86U units to keep them well below their maximum specs! Yell please if the list, photos, etc.. are unclear.

I've summarized my final results and made my recommendation for a fan which delivers the most quiet + best cooling performance using both 5VDC (USB) and external 12VDC PSU. Hint: They will be using the same fan!

 

[RMerlin]

Anyone going for blowing air in needs to use some sort of filter, otherwise they will just add a lot of dust inside their router, and ultimately make its thermal performance worse.

 

[elorimer]

I've said this before. All I needed to do was stir the air a bit. I have a little 12v fan running off the usb, stood on end about 6 inches away. That gives me the same 66C temp in a 20C room that strapping, taping, screwing the fan inwards or outwards did.

 

[Kees17760]

Yes, in every test I ran, blowing INTO the rear of the router delivered lower temps than pulling air through the router with the fan strapped on the rear of the unit.

See -> https://www.snbforums.com/threads/asus-rt-ac88u-to-hot.58405/page-2#post-518345
See -> https://www.snbforums.com/threads/asus-rt-ac88u-to-hot.58405/page-3#post-665525

I have I summarized a rough shopping list based on my findings in the post above # 665525. That's what I'm using on my 2 x AC86U and 1 x AX86U units to keep them well below their maximum specs! Yell please if the list, photos, etc.. are unclear.

I've summarized my final results and made my recommendation for a fan which delivers the most quiet + best cooling performance using both 5VDC (USB) and external 12VDC PSU. Hint: They will be using the same fan!

Ahhh, the proof of the pudding is in the eating

Did you notice any change in sound perception between the two?
And how much can the CPU reasonably be cooled down using a fan, as an offset to room temps (when running idle)?

I have a small (2 x 2 inch) fan screwed to the back of the router, with which i achieve a Tcpu of Tamb + 41 degr. C running 386.2b1. On 384.19 it was Tamb + 36 degr. C under the same circumstances.

There's also the internal (fourth) antenna to consider. I didn't want to obstruct it, so i've placed the fan on the right side (looking at the back).

 

[pinkgrae]

Why would it be better to push in?

I think maybe just a case of simple physics: in the case of a vertically standing AC86U router if you blow air in through the rear vents, it has to go somewhere, and I'm guessing most of it goes out through the top vents, as it can't go out through the front because the circuit board is in the way and the front is closed. As the hot air in the router tries to go out the top vents anyway, you're effectively enhancing the airflow that naturally occurs inside the router casing = efficient.

If you try suck air out of the back vents that air has to come from somewhere, which is through the top vents. Trying to suck air through the top vents back through the rear vents works against the airflow that naturally occurs inside the router casing, which is harder work, as it will likely cause some weird aerodynamics. This is inefficient and ultimately less effective in producing the desired effect (i.e. cooling).

 

[heysoundude]

@pinkgrae is onto something:

Ahhh, the proof of the pudding is in the eating

Did you notice any change in sound perception between the two?
And how much can the CPU reasonably be cooled down using a fan, as an offset to room temps (when running idle)?

I have a small (2 x 2 inch) fan screwed to the back of the router, with which i achieve a Tcpu of Tamb + 41 degr. C running 386.2b1. On 384.19 it was Tamb + 36 degr. C under the same circumstances.

There's also the internal (fourth) antenna to consider. I didn't want to obstruct it, so i've placed the fan on the right side (looking at the back).

the second picture, with the internal antenna highlighted - see the vents on the bottom?
it looks to me as if Asus designed the case to encourage natural (passive and silent) convection cooling - cool air in the bottom exhausting hot air out the top.
they'd have to redesign the stand (side legs?) to open them up more.
for anyone with an ac86 experiencing temps above 80C - how are those bottom vents of yours?

 

[gattaca]

^^^^ During my testing over a period of several days:

1. I heard no perceptible difference from 4' away (it's on top of a cabinet) between blowing in vs exhausting out in that setup. My ears are pretty good as these high frequency noises.
2. By using the 12VDC fans with the 5V USB, they are spinning about 50-60% of there "normal speeds" I swear the fans in my laptop are louder. This thing is moving like a "gentle breeze". When I tested the 12VDC fans at 12VDC, I used the ULNA or LNA in-line resistors which also slow the fans down to a gentle breeze with very little air-blade-noise.
3. Average room temp is ~ 22C-24C .
4. I'm considering trying the non-attached format where several other's posted @elorimer that they just sat their fans near the router blowing air in the direction from there rear. My only concern there would be pesky climbing cats knocking over things.
5. Note: There are vents in the bottom backside of the router which is where I think ASUS uses for intakes... if you look closely at the RT-AX86, they moved these lower "intake vents (red on that model)" to the front of that unit, away from cables, etc.
6. 10-4 on the internal antenna. An 80mm version would be well below that. I used what I had on-hand and a bit more plastic is not that large of a concern. I wish they would have just put the 4th antenna outside! I have no idea - outside of it costs more-Asus does not externalize all 4.
7. Yeah, it looks better using the "grey" Noctua NF-P12-redux-1300 fans vs the "standard" brown/tan" models I wasn't looking for super pretty - only super effective. I keep both of these up above eye-level, one on top of a cabinet, and the other in the top of a closet. Your WAF/SAF may vary!

Stay safe, stay alive. Peace.

 

[Adooni]

I think ASUSWRT and RMerlin are doing good job for temperature optimization as my RT-AC68U CPU temp is up to 84C. With Fresh Tomato my router temp was above 95C and router was not stable.

 

[Tech9]

@gattaca, I'm looking at your engineering design here:

asus RT-AC88U to hot

Hi! I am consolidating posts here of the "extra cooling" photos I setup which better fit this thread. As for whether our beloved ASUS routers "need or will benefit with a longer service life by keeping them cool" is up to you. We can argue all day long about the SOC or pCPU or other...

www.snbforums.com

With all the time you wasted in fan models research and cooling effectiveness analysis I was expecting to see at least 3D printed custom air duct with AC86U original design matching red stripe in the middle and RGB lights as un upgrade. What you have created ranges from highly disappointing to straight offensive to both Asus and Noctua. You are terrible engineer and I hope you have at least a little sense of humor.