Thanks to you!
The only reason I am even looking at air flow is because of your advice in this discussion.
At least this method now draws 100% outside air with a straight shot back towards the vital areas. Not bad for the first mod I have ever done on any computer other than replacing parts, plus it cured my loud fan problem and now, thanks to you, it will be even better.
Could you share some temperature differences, especially after blocking off the "basement backflow"?
I think it's even cooler now, the most it ever reaches with video, virus scan, and another program running at the same time is 85* F at the top with a thermometer laid on the vent. This is the best mod I have ever made on any PC, it completely knocked out my fan noise problem any it's funny how everyone downplays it as if only their $300 super duper water system with radiators will work.....lol. I think I have a total expense of about $12. (Whatever that Arctic fan cost), plus it was kinda' fun doing it.
Sorry, old thread revival and all, but I'm about to try the same mod on my XPS 8920 and had a question on the wiring for the 4 pin fan connectors.
Looking at your pictures, did you wire directly into the top fan plug, or did you use a splitter?
Reason I ask is that I've read a lot on here about Dell switching the wiring order compared to standard for the fan headers, that it can be difficult to tell sometimes and some Dell's use standard anyway. As far as I can tell the case fan header socket on the motherboard is 4 pin, do you happen to know if it is standard wiring on these?
I have an Arctic P12 PWM PST fan I was going to use, it has the splitter built in to the cable, so I planned to plug this into the motherboard, then the top case fan into the splitter. Obviously don't want to do this if there's a chance the fan or motherboard goes pop!!
Thanks for any help you can offer.
@simmil I have an Arctic P12 PWM PST fan I was going to use, it has the splitter built in to the cable, so I planned to plug this into the motherboard, then the top case fan into the splitter.
That is exactly what was done by @546insp in his mod. I don't know exactly how that built-in splitter works, but you might want to swap the fans, so the Arctic is the top exhaust fan and the Dell OEM industrial grade server fan is in the lower front intake position. The fan connected to the 4-pin cable will be the modulation 'master' and the fan connected to the 3-pin cable will be the modulated 'slave'.
I'll page @GKDesigns for an expert opinion.
My XPS 8930 i9-9900 MB case fan header is standard wiring:
pin1, black, Ground (-)
pin2, red, 12VDC (+)
pin3, white, RPM signal from fan
pin4, blue, PWM signal from MB
A 3-pin unregulated fan omits pin4 and will still work on a 4-pin header.
A 2-way splitter routes pin3 from only one of the fans, because the MB logic only regulates for one RPM signal. It is assumed that the other fan is identical and will follow at the same controlled speed.
A concern is that the two fans not draw too little or too much current, so aim for the current of the OEM fan. Too little current and the BIOS might error thinking the fan has failed; too much current might damage the MB. I would be most concerned about too little current... this problem can present when you replace one inefficient OEM fan with one very efficient after-market fan... so it's a good idea to replace the one OEM fan with two very efficient fans to get their combined current up to keep the MB fan logic happy.
Sorry I don't remember, it's been a while. I see others have chimed in though...……...