Weissach1982

I'm removing my smog pump and Viscosity fan and was wondering if there was a way I could use my Aux fan instead of buying a new one?
Would I have to buy a fan controller or any other parts to make this work and would this fan put out enough CFM to keep things cool?
As of now, with the clutch fan my temp never goes above the first white line, even sitting in traffic for long periods of time. So if anyone could get back to me on this, that would be great.
Cory J.
82 Weissach

Paul D

Cory - If you are thinking of removing your viscous fan and only replacing it with the front mounted Aux. fan you may not have enough CFM to keep things cool. Here is a link on some Perma-Cool Fans that I was contemplating using when I was replacing my viscous fan with electric fans. They give some basic guidelines as to how many CFM's you need based on engine size. I eventually went with a set of electric S4 fans because I thought it would be easier than trying to find an aftermarket set that with the same form, fit, and function of the S4 ones. Besides, Porsche already did the engineering on them why should I try and reinvent the 'wheel'. The only custom part I had to make was the wiring harness. I did not use the S4 fan controller which is certainly an option. I bought an after market thermal switch for each fan (turns on at 175F and off at 165F), and they work great. BTW, if you go with the S4 fans and shroud you'll need to replace the lower radiator hose with the S4 type lower rediator hose. Good luck!

Weissach1982

What size fan is the aux? I would like to try that fan first to see how it does..but if it doesn' cool enough then i'll buy some other kind of aftermarket fan setup.
Cory J
82 weissach

Paul D

I don't know what the aux fan will push CFM wise. I'm sure someone out there knows. My guess is that the CFM of the aux fan is less than the CFM of just one of the S4 fans. My S4 fans are wired to 12V (the S4 controller actually varies the fan voltage based on airflow needs) so they are going full tilt when they turn on. Those fans can move some air!

PorKen

Cory,

I did just what you're describing and have had no problems, even during the summer. Only thing I did was to change the fan switch in the radiator to a lower 75c (~$12).

However, I have removed my A/C parts, and I live in the Pacific NW. I doubt if it will work well if you use your A/C down in FLA.

...

If you do take out your air pump (so that it doesn't wear out!), you might want to squirt a little light oil down inside so that it doesn't freeze up while in storage.

Weissach1982

Hey Paul,
What was involved in wiring a fan controller and all the parts up to your 82 in order for everything to work with a thermostat etc. That is where i'm lost. I can get a fan/fans with adj thermo and fan speed, but hooking everything up and routing where the wires need to go is my prob. Could you give me some info on what I would have to do in order to hook things up?
Thank you for your time,
Cory J.
82 weissach

Drewster67

Please be serious and realistic. I dont think the smog police will be coming any time soon. If I had a dollar for every one who bypassed a smog pump I'd be a rich man. Besides the 1/4 hp is more like 5-8hp.

Cory, the aux fan "may" work if you

1. remove the a/c condesor
2. mount the fan closer to the radiator.

I think the fan moves enough air but there may be a "power" issue under a full load. Im not sure if the alt. can handle such a draw for x amount of time. But I could be wrong. Any insight anyone?.

TIA

Weissach1982

Would aftermarket electric fans draw more current from the Alternator than the AUX fan? Yeah, wish i could remove a/c condensor, but I'll probably just wind up buying an aftermarket fan if the aux won't be up to snuff. What size aftermarket would be adequate for pulling some CFMS?
Thanks,
Cory J.
82 Weissach

Drewster67

18" - Summit Racing has a slew of a/m fans. You'll need a puller rather than a pusher. For around 170+ and some change you can buy a fan that can handle cars the push 300hp. http://summitracing.com/

BTW - Is that snot nosed vette owner still giving you grief?. (No offense to those who own vettes)

Flex-a-lite Black Magic Electric Fans
Up to 17 free horsepower from a fan change. (More like 10)
By replacing your stock, engine-driven fan with a Flex-a-lite Black Magic electric fan, you can get back up to 17 free HP that the stock fan was stealing. With a powerful motor and steep blade angle, the Black Magic can move up to 2,800 cfm of air--enough to cool off vehicles making 300 horsepower w...

PorKen

I forgot.

I did have to replace the aux fan fuse with a breaker, because the fuse got too hot after extended fan operation, even after cleaning the fuse contacts.

Weissach1982

Drewster-
I'll have to look into those fans at summit and flex a lite. Finding the fan isn't a problem though, its the wiring i'm concerned with on where the fan switch is on the radiator and what kind of relays/fuses etc..I would need to make things work.

-( ''BTW - Is that snot nosed vette owner still giving you grief?. No offense to those who own vettes)''-Nope, hes full of himself and i'm his only rival at my shcool in road course, hes full of himself because he knows his car will out accelerate mine, but I told him its apples and oragnes man. I even invited him to challenge me to an SCCA autocross a few weekends ago...he didn't show and he shut his trap after i told him I was 2 secs behind a newbie with a 350z plus it was my first time and i was last in my class with 2 944Turbos and 2 350zs, but its all good I LOVED IT!

-PORKEN-Oh and I very rarely use my a/c, the blower makes a god awful noise when its on and plus 60mph with the windows down is good enough..although i have to buy a new passenger side window motor (dead) lol. What fuse are you talking about in your above post?
Thanks all,
Cory J.
82 Weissach

Paul D

Cory - I bought 2 fan temperature switch kits. (I'm sure many auto stores sell them). The kits usually contain a thermal probe/switch which senses temperature and a high current relay which turns the fan on. The the thermal probe/switch is used to turn the high current relay on and off which in turn powers the fan on and off. You'll want to make sure the current rating of the fan switch will handle the max. current of the fan. Each S4 fan is fused at 30 Amps which is alot of juice. After market fans will typically draw less current for similar CFM ratings. On my setup I removed all the AC components since it was not working anyway along with the aux fan. Each fan switch comes with some type of temperature probe (some types install in the radiator hose, while some are installed in the cooling fins of the radiator). Mine was the probe type that installs through the radiator cooling fins. I wired each fan to its own thermal switch. The passenger side fan probe is near the upper radiator coolant inlet while I used the factory thermal switch for the driverside fan located in the driverside bottom radiator side cap. I did not want to turn both fans on simultaneously by using only one thermal switch since it could potentially draw 60 Amps (alternator probably wouldn't like that). You will typically need to find a 12 V wire that is switched with the ignition switch which is used to energize the high current relay (fans will not run unless the ignition switch is on). I found a switched 12V wire in an unpopulated relay connector on the fuse/relay panel. You will also need a high current lead which will provide the necessary current/voltage to power the fan. I ran heavy gauge wires (12AWG) to the battery jumper post located on the passenger side of the engine compartment. Last but not least, you will need the same size heavy gauge wires to tie the (-) side of the fan(s) to chassis ground. There are several ground points on the front bumper area that I used. Hope this helps.

ViribusUnits

The aux fan is not enough to cool a 928 in stop and go traffic with the a/c on.

Ask me how I know.

Even after killing the a/c, it wasn't really enough on a 100`F day. Not without a bit of highway driveing. the temp went all the way up to the top read line before I got into the highway where it proceded to come back down to normal.

Weissach1982

Well I guess i'm going to invest in an aftermarket fan. I'll probably buy a single 14-16 inch fan from Felx a lite. Are there any precautions i might want to take when removing my smog pump and visicosity fan?
Kind of off subject, but a few posts commented on the Alternator only having 75amp put out. Do later model 928 Alts put out more amps, if so i might need to purchase one or some kind of aftermarket one. Because right now my volt guage bounces and lights dim everytime my stereo hits, I mean i ''only'' have 2 soundstream Rubicon 10s and a JBL 1200amp(cool,if any of you are stereo nutts), but... I would like to know how to get more amperage by either better alt or just turning down my stereo a notch or two lol.
Thanks guys, your help has been great,
Cory J.
82 Weissach

Drewster67

You'll need to either plug or fabricate an air filter for the smog pump return line. I'm still messing w/dialing in my shark (prior to my broken bolt nightmare still in progress), Iv "experimented w/running an open and closed tube but still am unsure.

Yes, the later sharks run higher amp alts. My S2 runs a 90 amp Paris Rhone. But then again it could be just a alt "type" issue. Anyone care to comment?. Looking for clarification myself.

Happy Motoring!