View Full Version : Thermostat is a 180 deg. at what temp do I have the fans kick on?


Flyman
10-28-2004, 07:28 PM
with a new 180 degree thermostat what temp. should I have the fan turn on?

195, 200???



Thanks

SmokingWS6
10-28-2004, 08:33 PM
195, 200 is a good setting

off 190, 196 or so

jimmyblue
10-28-2004, 11:03 PM
Where do you really want your ECT to be?

You might set both fans to be on full time, and
drive some logging ECT. You will see the ECT swing
from its lowest at idle / low cruise to its max for
hard driving. I prefer to set my fans so the low fan
turns on just below the stable minimum, so it runs
full time but doesn't interfere with warmup. The
high fan I want on before the thermostat hits the
top of its opening to keep it in control. This makes
for the tightest temperature swings without making
the high speed fan run excessively. I put off one
degree below on.

If the fans kick on after the thermostat is fully open
then you are just allowing more temperature swing,
and your worst pretty much sets the spark timing
you can stand.

SmokingWS6
10-28-2004, 11:08 PM
I like to keep my high fan about 10 degrees above what my low can reasonably maintain so it wont run excessivly. If its about 60* or below outside my low will occasionaly shut off on the highway. Its also bad to be stuck making your 1/4 run with the high fan on. I have fan switches so if I want to keep it as cool as possible i'll manually control it.

tici
10-29-2004, 06:08 AM
I agree with jimmiblue, but Iwouldn't go with the rating of the thermostat: the value usually sucks. Also the temperature you see using Atap is not the same as what the PCM will use to command the fans (dunno why...) Better you put a lamp or a voltmeter in parallel to one fan to see when it turns on and off.
Thermostat: the aftermarket style has a slow warm up, it leaks somehow and in winter it's a pain.
I ended up modifying the stock one: I drilled an hole and tap a M4 thread right in the middle of the seat. It's adjustable! From the outside you can change the lenght of a bolt to adjust the temperature ;)

http://memimage.cardomain.net/member_images/4/web/460000-460999/460473_76_full.jpg

jimmyblue
10-29-2004, 09:03 AM
The real ideal I think would be a thermostatic fan
control that ran off radiator tank temp rather than
water jacket temp; make sure the tank is always
held below thermostat pivot temp so the 'stat has
some "authority" backing it up for thermal surges.

What I described was a way to find, at least in terms
of what the PCM "thinks" is going on, the real thermostat
control range and adapt the fan settings to that. The
ratings on the box are known to be bogus (15 degrees
lower than actual working temp point roughly). I have
not seen any discrepancy between commanded fan and
actual fan action points however.

samz28
10-29-2004, 02:24 PM
if you are automatic you want all the help you can get (cooling wise). otherwise i'd raise the temps up when not drag racing to let the engine burn the fuel most efficiently.


keep in mind when its freezing out there and you're whippin down the autobahn with your m6 you could drop too cool. This could cause enrichment (cold start) to kick it. Or if oil temps get too cool it could lose its ability to lubricate and keep water out.

Some folks up in canada actually cover up their radiators in the winter for high way trips to keep ECT up. This would be a scenario where you would want to put a 215 back in if you do alot of freeway driving for winter.

summer temps change of course cause its damn hot.

J&JsTA
10-29-2004, 02:38 PM
if you are automatic you want all the help you can get (cooling wise). otherwise i'd raise the temps up when not drag racing to let the engine burn the fuel most efficiently.


keep in mind when its freezing out there and you're whippin down the autobahn with your m6 you could drop too cool. This could cause enrichment (cold start) to kick it. Or if oil temps get too cool it could lose its ability to lubricate and keep water out.

Some folks up in canada actually cover up their radiators in the winter for high way trips to keep ECT up. This would be a scenario where you would want to put a 215 back in if you do alot of freeway driving for winter.

summer temps change of course cause its damn hot.


These numbers were popular a year ago for the different temps

Stock Thermostat, lower your fan settings to:

FAN 1 ON/OFF: 209/200
FAN 2 ON/OFF: 219/210

180 Thermostat set to:

FAN 1 ON/OFF: 194/185
FAN 2 ON/OFF: 204/195

160 Thermostat set to:

FAN 1 ON/OFF: 184/175
FAN 2 ON/OFF: 194/185