RotaryRevn

I have a series 4 turbo motor being run by a microtech. The microtech can turn my electric fan on/off. What temp do most of you have have your e-fan turn on?

thanks

RotaryResurrection

iTrader: (8)

about 195 on and 185 off would be ideal IMO. Most switches are rated 205-215 in oem applications, though, and the aftermarket adjustable versions are usually pretty inaccurate. You'd better have a strong charging system/alternator to run an e-fan, though...s4 alts usually do not do well with them at all. Heck, s4 alts usually do well to run a stock FC with no electrical mods/extra demands.

RotaryRevn

Thanks for the info The motor is actually in my first gen so I'm hoping that the electrical need's aren't as much as the 2nd gen.

RotaryResurrection

iTrader: (8)

What chassis it is in really doesnt matter. The alternator doing the charging is what makes the difference...and of course the size and health of the battery, and proper clean connections on all the power cables.

A good size e-fan can draw 20-40 amps, and the s4 alt is only 70 amps. And most of them aren't performing 100% after 20 years either, so you can see why this is an issue. On a stock s4 I often see as little as 12.5 vdc at idle with no accessories on and no e-fan. Turn the lights on and you see 12.3 or 12.0. Then add an e=fan and see what you get. Sometimes a charge/ground wire kit helps, sometimes you need a rebuilt or upgraded alternator.

JYM

I have my efan turn on around 89-90 degrees Celsius, just because as the temperature of the radiator increases, heat transfer is more efficient (since the heat difference between radiator and incoming air is greater). Also, this way my fan doesn't turn on while I'm on the freeway (on a normal day it'll be around 85-86 degrees Celsius on the freeway).

But that's just me and the reasoning I used.

RETed

I have my SPAL-PWM turn on 100% @ 205F.
The SPAL-PWM can be set for 50%, which I have mine set @ 195F.
It turns off automatically under 195F.
With these settings, the temp tends to overshoot a little to about 220F.
Anything lower and the fan cycles a lot.
With these settings, the fan doesn't cycle as much.
The stock electric fan used to kick in @ 225F, according to my SPI water temp gauge.


-Ted

RotaryResurrection

iTrader: (8)

The FC stock aux e-fan is controlled by a 207* temp switch on both s4 and s5 models that had the fan. It's just meant as a failsafe/backup and to aid in a/c function, not meant to cool the actual engine primarily.

J-Rat

iTrader: (2)

I think my on temp is about 203 and my off temp is about 195.

RotaryRevn

Thanks for the ideas. I did notice that with my headlights on and the fan going, the idle would drop. I probably need to look into an alternator upgrade.

Icemark

Changed Kevins reply to say 70 amps... the stock S4 alt is only 70 amps peak, the S5 alt is 80 amps peak output.

RRTEC

iTrader: (13)

I always set mine to kick on at 185deg.

RotaryResurrection

iTrader: (8)

IT was always to my understanding that s4's were 80A, s5's were 90A, and FD/rx8 are 100A. I have never had one load tested to verify, however.

I see captain-save-a-thread is in here combating the evil of minute technical inaccuracy for the good of all and changing my posts. Thanks for that.

NZConvertible

You should look at your BAC valve too. It should compensate for extra alternator loads and keep the idle speed up. Assuming you still have it...

That's pointless. The engine hovers around that temp in normal driving, so the fan will run far more often than is required. Turning the fan on any earlier than 90degC/195degF is totally unnecessary.

The correct info (S4 70A, S5 80A) has been posted hundreds of times and is easily found in the FSM's. Dunno how you could've missed it.

Who pissed in your cereal this morning? Being out by 13-14% is well beyond "minute technical inaccuracy"...

RotaryRevn

Yeah, unfortunately no bac valve, it's been blocked off...... I reset the fan to come on at 90c when I was messing with my microtech this morning. I'll try it out. thanks everyone!

NZConvertible

Without a BAC valve the idle speed will always dip when the fan or headlights are on, because there's more load on the engine from the alternator. An alternator upgrade won't fix that.