modding fans

[MrP]

right,

i have a small mountain of 80mm fans here that seem to have very little output, the highest output seems to be around the 33cfm mark.

now, as all that changes on a fan is likley to be the speed controller (the bit that keeps it at 2500rpm or whatever) is there anyway of overclocking(!) this bit??

i assume it would be a bit like a volt mod on a motherboard, IE a variable resistor and some bits of wire, or is it more involved???

toodles :xsofa:

[BigBen]

Hi MrP,
I just tested a 80mm Delta fan with 12v and then put 24v through it and yes it went quicker and louder if that is possable ....not sure how long they will last though :D


Regards

[MrP]

BigBen,

thanks for that.

was really looking at making them go faster with just 12v rather than 24.

was thinking that the fan would be goverened by some kind of speed controller that you could bypass. judging by what you just tried though, there isnt one, so i wont be able to do much

thanks anyway :)

toodles :xsofa:

[Player0]

MrP,

Fans are sort of designed to have a natural rpm at a given voltage. You cant really change it without changing the design of the fan really.

Your PSU has -5 and -12 lines. If you hooked up positive of the fan to the +12v line, and the negative of the fan up to the -5 or -12v line, you can make the fan go faster, because you are giving it 17v or 24v respectively. 17v might be a good spot for fans, not too much more to cause damage, but will improve performance.

Now, becareful, you dont have a lot of watts to play with on your -5 and -12 lines. Might be enough for one or two fans, depending on your PSU.

[JaFFa]

where is the -12 and -5 rail on the molex isnt it 5-G-G-12 ?

[Player0]

Its on the ATX power connector. You can buy an ATX power connector extension for a couple dollars, and then splice wires off of that to add power to the fans. THat way you dont have to cut the wires on the PSU itself.

No one said it would be easy :)

[JaFFa]

by an 'atx power connector' you mean a bunch of 4 wires with a molex on the end?
If so what are the voltages on those wires, whats the order?

[Blackhawk]

I don't recommened that 24V thingy. I asked once cause I have 2x 24V 120mm Comair fans and everyone told me that doing that could be bad for the PSU. They said to buy a seprate 24V PSU. In your case buy new fans................

[Player0]

Jaffa, no. I mean the big ATX connector with like 20 wires in a rectangle, the one that plugs in to the motherboard. It has the -5 and -12 lines on it. See your PSU documentation to determine which wires are the negative lines.

Blackhawk, wiring a fan to use 24v like this will have no adverse effect on the PSU. Just make sure to watch the wattage. You only have 1-2amps to play with on the negative lines. Good for one maybe two fans.

Now, it probably wont be too good for the fans themselves :)

[JaFFa]

thanks player0 for clearing that up, I'll look into getting one in the UK. Any UK dudes know where I can? (cheap!)