slate blue

Hi guys, I am getting ready to fit my new thermo fans, I bought a new GT radiator and a set of genuine fans but have at present no means to control them. I have a couple of questions, one how much current do these fans draw? Two I have three options on how to control them, first, connect the factory system up acquired from a wreck, sounds good but might be complicated, second option is a local fan control unit, it does everything the Porsche unit does except it doesn't have variable speed control. The maker says variable speed control for the fan is a nonesense.

The reasons given were that a fan blade has a best operating speed and you should only run it at this speed. He said let the thermostat regulate the water flow and temperature. regulating the fan speed is tinkering at the edges.

Third option is DCcontrols which is a U.S company and it can do everything the Porsche control unit can. It costs double what the local unit costs and there would be a slight delay in getting it, due to postage and the time of year.

Please any thoughts and what have been your actual experiences?

Thanks Greg

928FIXER

I converted my 79 to electric fan 14 years ago.I just used a 944 3 prong switch and a 944 dropping resistor to make it have 2 speeds and wired it so that it cames on low speed with a/c on

drnick

my twin kenlowe fans are switched by the thermostat on the front bottom of the radiator, simply on and off.

SharkSkin

Greg, I think the goal with the variable fan speed on the later cars was more along the lines of managing electrical consumption than trying to gain fine control over cooling.

ErnestSw

Each fan has a dedicated 25 amp fuse at the fuse box.

Fabio421

My fan runs full time. My PO wired the fan to run all of the time after the temp. switch went bad. I have a new temp. switch but have never installed it. The temp. needle only climbs to one needle past the first line on the guage. I have seen lots of people complain about their cars running hot so I have left it alone. I suppose the fan may not last as long but so far I have been running it for one year and theres no telling how long the PO ran it this way. So I guess its not a a huge problem. Save yourself some time and run 'em full time.

Paul D

Greg - I made this upgrade 2 years ago and here is what I did. I used the factiory shroud and twin fan setup connected to 2 different thermal sensors. I purchased 2 high current electric fan kits from AutoZone (simple and inexpensive). I went with 2 fan switches since each fan requires a 30Amp fuse (total of 60 amps) I thought that hitting the alternator with 60A by using a single switch would be too much stress on the alternator. Besides, you'd be hard pressed to find a switch that will handle that much current in an auto store. I initially tried 25 Amp fuses but blew those immediately when the fans turned on. For the first fan (passenger side) I installed the thermal switch from the AutoZone fan kit near the radiator inlet (upper passenger side). It is a probe that is inserted between the cooling fins of the radiator. I was initially against this type of probe but so far has worked flawlessly. This fan comes on first when the coolant gets warm. For the second fan, I used the factory thermal switch (lower driver side) this usually comes on when trolling around town and both fans are on. I currently do not have any way to vary the speed of the fans. They are either full on or full off. Using 2 thermal switched minimizes the chances of both fans coming on simultaneously. These fan kits allow you several differnt wiring configurations and usually will have an aux input where you could tie your AC into the switch so the fan is forced on when the AC is turned on. I ended up wiring an extra switch for each fan so I can manually turn them on. I hid these switches in the tray below the steering pod.

heinrich

I think I'll do that with my '85 sibce my '87 won't need the shroud and fans. Hmmmm So it seems strange S4 alternators can handle the draw?

jpitman2

I am also in last stage of doing this. I have a Kenlowe switch (sensor in top hose, bourdon tube to adjustable switch, to relay). I have one 14" fan (already in hand) on rhs (car wise), one 10" fan on top of other side. Together these 2 cover nearly the same area as a single 16" unit. Currently with a 75C radiator switch in lhs tank, the factory fan cycles in too much, so going back to original 92/87C switch. The sensor/relay supply comes off switched 12V (ie only with key at least at Acc position), but the main power is fused off the engine bay hot point. You might also tap switching power for relay off the main original fan power. Note that Wahler (the switch maker) also make other switches that look same thread in 3 pin types, allowing for 2 temperature switching - at least 85/80C with 93/88C and some others I forget - common on some Audi and VW models. The two pin units seem to be ~$15, the 3 pin/2 range ~$21 in US. My idea, if the 92/87C allows temp to climb too much, is to get an 85/80C switch and use this circuit as a compromise range. I made up an alloy angle frame bolted to the original shroud mounts, and cut an old damaged top shroud up so I have the cold air intakes in place, and installation looks close to std. One odd thing came up - I borrowed a dead core (S4) to build the frame on, and get all the fans fitted up etc. When I tried to fit it on my S radiator, the fan mounting bolts hit the core?? On close examination , the S4 core is ~8-10mm thinner than the 83 S core, and the cross tubes are probably smaller to match this.
jp 83 Euro S AT 49k.

slate blue

Interesting guys, all great responses, please keep them coming. Facsinating that the S4 core is thinner than the S.

Cheers Greg

Ketchmi

Hey Greg,

The link below is what we are using on our fan systems, it works great! You set the turn on temp anywhere between 160 and 230 F. It comes on at 60% fan speed and ramps up as the temperature increases. It also has inputs for A/C and manual on and off switches (for those deep water crossings down there!) They make a heavier duty one that has twice the capacity but there is no need if you are using two smaller fans. The larger one is for big trucks with heavy duty fans. We use two 2950cfm fans that draw about 9 amps each without any problems. Measure the current of the fans you are currently using and you will see that the 25 amp rating of the model number 31165 is more than enough to run the S4 fans.

We could have thrown one in with your head studs...

http://www.flex-a-lite.com/auto/html/vsc.html

slate blue

Got my thermo fan control today from Motorsport, it looks real nice and small and light too. Very glad I went down this direction.

Ketchmi

I'm happy you like it, they work great for us. Here is a photo of one installed inside the shroud on our fan system, it's attached by the two bolts you can see on the top of the shroud. It's easy to hide and it's powering two 14" perma-cool high performance fans in this system with no problems so far.

jpitman2

After some local testing my 14"+9" fans seems to work fine. A couple of cool days first then a 34C day, no real change in behaviour of temps visible in stop/go and AC on. Along the way I seem to have disturbed the power steering supply/return hoses and the oldest part let go a bit, so I had to replumb that area. To get the 10mm ID return line to meet the reservoir 12mm inlet (whoever thought that up needs a kicking!) required fittings to turn a right angle and change diameter, but its all back together now. Significant reduction in noise is apparent, and makes it all seem even smoother then before.
jp 83 Euro S AT 50k

lorenolson888

Hi Dave,

I could not find the product mentioned on your website. Do we order it through the link you gave previously.... or should we call you... I have a devek fan shroud that I have never put in... I think it uses two hayden fans...

THanks,

LO