T2 Electric Fans question

ChrisL · June 05, 2012, 03:03:56 PM

Hi guys, here\'s my first ever proper question!!

I bought my FC with the intention of drifting it, so to keep things nice and cool I\'ll be sticking some electric fans on the radiator.

I\'ll just be wiring them up on a switch on the dash.

Is there any jigery pokery I need to do to keep the ECU/thermostat happy?

Thanks all!

m1tch · June 05, 2012, 04:29:08 PM

You need to run a relay to run the fans due to the high current drawn, I would also suggest running electric fans on the intercooler as well to keep the intake charge temp down.

ChrisL · June 05, 2012, 05:39:53 PM

I was going to run a fuse with each fan, still require a relay as well..?

If temperatures are getting a bit much under there, I\'ll take the bonnet off. Could get a little cramped with fans on the top mount...

I\'ll eventually head to a front mounted cooler.

Kodiak · June 05, 2012, 07:23:01 PM

You guys got any specifics as I\'m planning to do this within the next fortnight?

Prof · June 05, 2012, 07:30:49 PM

Quote from: ChrisL;825358I was going to run a fuse with each fan, still require a relay as well..?

If temperatures are getting a bit much under there, I\'ll take the bonnet off. Could get a little cramped with fans on the top mount...

I\'ll eventually head to a front mounted cooler.

Yes the relay will still be needed

The starting current for many electric fans can be 20+ Amps, maybe more - that\'s a big ask even for a large switch, and will cause some arcing each time you operate the fan. Using a relay, you can run much thinner wire to the relay from the switch which avoid heat and losing voltage in the wiring, and you can then keep the fan wiring short and run it from the battery.

The 12A running current of the volvo fan I had ran nearly 45A of in rush current when it started. You\'ll probably want a larger fuse type - like the maxi blade, as the standard blade fuses will just keep popping.

Kodiak · June 14, 2012, 04:38:32 PM

I was going to put 2x10" fans on staggered but how would I go about making it so that if one failed it wouldn\'t cut the other one off? :confused:

I would hope they wouldn\'t fail but I\'m useless at fathoming electrics generally!

ChrisL · June 14, 2012, 05:21:51 PM

I was going to run both fans off the battery for power, but then run a relay, fuse and switch per fan, so effectively two different circuits.

Should keep one alive if the other fails, and keep things cool enough to get home/back to the pits to fix/sack it off/bodge it.

Prof · June 14, 2012, 05:52:06 PM

You can probably run each fan through it\'s own fuse and relay, but wire the relay coils in parallel to the switch. If one fails, you can always remove the fuse for that fan circuit, leaving the other still working fine.

Kodiak · June 15, 2012, 04:57:37 PM

Ahh right. Cheers guys :Thumbsup!

Kodiak · June 20, 2012, 09:38:39 AM

Fans = 12v, 10A

What size (amperage) wire do I need?

One how to stated it was a fraction of 10A, another stated it was a wire capable of 30+A

Really wishing I hadn\'t had a drunkard as an Elec-Mech teacher at College...

Kodiak · June 20, 2012, 11:10:14 AM

I\'m assuming that the wire will have to match the spec of the fan (10A) but will it need to be beefier to cope with surging and if so by how much?

Reading the how to on www.aaroncake.com there\'s a black and yellow wire on the right hand side of the engine bay with a switched 12v supply that I can loop the relay into. But since I\'m using 2 fans/ 2 relays/ 2 switches/ 2 fuses will I need to splice the second fan relay into a different wire?

Cheers

Prof · June 20, 2012, 04:21:37 PM

Quote from: Kodiak;826991I\'m assuming that the wire will have to match the spec of the fan (10A) but will it need to be beefier to cope with surging and if so by how much?

Reading the how to on www.aaroncake.com there\'s a black and yellow wire on the right hand side of the engine bay with a switched 12v supply that I can loop the relay into. But since I\'m using 2 fans/ 2 relays/ 2 switches/ 2 fuses will I need to splice the second fan relay into a different wire?

Cheers

I\'d wire both fan circuits directly back to the battery - none of the existing wires have really got any spare capacity.

Kodiak · June 21, 2012, 01:54:12 PM

As well as the Switch power sources?

Prof · June 21, 2012, 02:39:42 PM

No, the switch should only be carrying a few tens of milliamps to energise the relays, so they can be fed from just about any suitable power source (fused).

Because I had my fans wired to work with a thermostat in the top rad hose, and also an Emanage Ultimate piggy back, I fed the relays from an always on (but fused) 12 volts, so that when the car was parked up and the ignition removed, the fans could still run to cool the radiator after heavy running.

You do have to be careful of alarms in that respect, as some alarms use a voltage drop sense on the battery, and if the fan was to operate whilst the alarm was armed, it would set it off.

Kodiak · June 21, 2012, 02:58:00 PM

Well if I\'m feeding the fans direct from the battery and fit a thermostat into the spare hole in the rad at a later date I could also have a delay on the fans?

I suppose I could feed the switches from the Cigarete Lighter as I don\'t intend on using it?

Also, regarding cooling, I bought a Godspeed radiator for the FC from America.

Stock Fitment ,Fittings for ancillaries in all the right places and dual flow. Not to mention, MUCH thicker... No idea how much of an upgrade it is but it certainly looks well engineered.

[ATTACH]54907[/ATTACH]

Little pic of the old vs. new.