88911coupe

Just caught this thread...is over heating an issue with the 996 in hot climates? I fight this with my old '88 Carrera but I assumed Porsche had finally addressed this...

washington dc porsche

Relative discussions.. I doubt anyone in this post is speaking of literally "overheating". I think it's more of staying below 215 degrees which is far from being close to overheating.

white out

bumping an old thread.

Are there low speed and high speed fans or is it one set of fans with two speed settings?

fpb111

One set two speeds. With a resistor to determine which is chosen. The resistors can burn out and compromise the system.

wwest

996 works well in HOT climates w/HARD driving just as long as fans/blowers are all fully functional and radiator/condensor air intakes are unblocked. Still not a bad idea to reduce the heat load on the radiators (and get a slight increase in FE) by closing down or disabling(***) the climate control system's reheat/remix cooling moderation technique.

***Install a manually operated water flow blocking valve to prevent HOT engine coolant from reaching the heater core INSIDE the A/C plenum.

wwest

Resistors are OUT in favor of solid state semiconductor PWM power switching for inductive devices. Or in some cases running 2 fans, low speed in series, high speed in parallel.

DreamCarrera

Questions about the fan mod that allows both radiator fans to run at high speed with the flip of a switch.

With the hot summer weather just around the corner coupled with the fact that these cars(996s) engines like to run really hot, I'd like to do the fan mod to my 996.

I'll be the 1st to admit that I'm not an electrical engineer, so I have a couple of questions for those of you who have already done this mod(or are electrical engineers...LOL). The 1st page of this thread has instructions for performing this mod but they are a little unclear on some of the fine points.

I will be using a toggle switch for the mod and I understand that one connection on the switch will be the ground which will run from one prong on the switch to a ground location on the chassis. Should I simply run it to any chassis screw location near the relay panel by loosening the screw and wrapping the wire around the screw before I re-tighten the screw?

As for the second prong on the switch(I'm assuming it takes only a two-prong switch...is that correct?) which is connected to the ground location on both high speed fan relays(relays #20 and #22), how do I go about making these connections? Do I run two separate wires, one from each relay, and then attach both of them to the same connection on the switch? Also, what gauge wire should I use for this mod?

TIA for any help...

BAD.TAG

^ +1

A picture of the relays involved would be great. Electrical work always worries me..I imagine flipping the switch and frying all my computers in one shot.

DreamCarrera

Here's a link to a relay diagram for a 2000 Boxster, which I believe has the same relay panel(and layout) as the 996.

http://www.theschillings.com/boxrelay.htm

Tbred911

or this can be accomplished as you previously mentioned by running the AC on MAX cooling, recirculate mode and no windshield flow right? I am assuming you are using a cabin fan speed of 1 (lowest) so it doesn't freeze your face off here...

BAD.TAG

Thanks for the link.

I was hoping someone would post up a picture of a relay to show which contact to wire into, but maybe its simpler than I think and only has 2 which are clearly marked +/- ?

BAD.TAG

Took a look at my relay set up and its a bit different than the diagrams DreamCarrera posted (though that was appreciated)

It seems that most of the people doing this mod are Mk1 owners and for MkII they changed the layout. The second row up where 19-22 are in Mk1 is largely blank on mine.

Its possible that these were simply moved to the bottom row so I removed one and took a pic.

Can anyone verify if these look like the Mk1 fan relays and if pin 87 is the one to wire into?

Thanks for any help

DreamCarrera

Thanks for clarifying this...I should have mentioned that I believe the relay panel of the 2000 Boxster, for which I posted a link, is the same as a 996 MKI relay panel. From your post, it definitely appears that the MKII panel is a bit different.

I'm still hoping someone who has successfully done this mod chimes in to give us full details on doing this fan mod.


OT: Brett(BAD.TAG), I clicked on the link in your signature...WOW...awesome photos!!! I'm a huge Grand-Am fan and really enjoyed the Grand-Am action shots on your site.

thstone

My 996 has been running a little hot lately so I checked it out over the weekend and at least one of my relays is inop. Will replace the relay. Thanks for all of the good advice.

BAD.TAG

Thanks! Always nice to hear your work is appreciated . Let me know if you have a particular fav and I'll give you the RL price