U-928

For a street driven 928, equipped with a stock 82*C thermostat, what would be the preferred turn on temp for electric radiator fans?

I'm having a hard time deciding on what temp sensor to buy, as I'm unhappy with my old arrangement.

New England climate.

180*F? 185*? Hotter?

TIA.

ramcram

I set mine to turn on at 90C, 195F. I'm just in the process of fitting a new temp switch into the water bridge, near the temp gauge sensor and it turns on at 95C and off at 90C.

GlenL

Make sure to measure the temperature of the water returning from the radiator. Otherwise the fans come on whenever the engine gets hot. And not "too hot" but just hot.

Notice that Porsche puts the temp sensor near the outlet from the radiator. This turns on the fans if the forced flow from driving isn't enough air.

Ducman82

i have my electric fans set to come on at 180ish. as close to the thermostat temp as i could. the sensor for the controller i have is in the rad fins, down by the lower intake hose.

U-928

Good point. This makes me re-evaluate what I was going to use to turn the fans on. Inline temp sensor in the lower radiator hose should work, as I'm not too keen on sticking probes through the fins. Thanks for the input guys.

Ducman82

ya, im not key on probes either, but this little guy is ok. its not a giant one like most aftermarket kits.

http://www.dccontrol.com/constant_te...ontrollers.htm

for my MS conversion, i did tap the temp II (i think) sensor hole next to the heater hose line on the T-stat housing.

U-928

I have used them in the past, with great results, especially in the long term. It was on a $100 radiator though, not a $700+ one like in our sharks.

This is the one I've had very good luck with on my VW projects.

Derale 18748 Temp Switch

I haven't integrated fan control into any of mt past MS projects, but it's on the to-do list when the new motor goes in with MS3x.

OBehave

Jeremy, I use this on my track car with dual electric fans and my DD 85 wired to the A/C fan in front of radiator. It wires direct to your temp gauge so there is no need for a separate sending unit and you can adjust the on time to whatever temp you desire and it's priced reasonably.
Ed

http://www.centechwire.com/catalog/cooling/fc2p.shtml

svpmx83

I'm running twin S4 fans in an 81 Euro S with a microsquirt controlling switching

I run series for slow speed and parallel for high. using the engine temp sensor in the water bridge and two outputs from the microsquirt

Slow speed turn on is 50C and over 400 rpm
High speed switching is set to 94C

in our subtropical climate temp remains static at around 95C with the AC on and with the fans cycling in and out of high speed nicely when the car is stationary