Nikoncamera

Hi guys,
I want to fit a 993 turbo fan pulley (not the whole fan unit) to my normally aspirated 993, as it is a smaller diameter, and should spin about %15 faster at any given revs.
Is this possible? ( the porsche dealer seems to think it will work) Has anyone else done this?
It seems like an easy way of getting more cooling, for only about $80.
Thanks Lyndon.

Rezal

Have you had cooling problems? If not, why bother?

I've never had any cooling issues, even on the track, with the engine cover on. If you haven't done so, you might consider removing your engine cover as well.

Jeff 993TT

I agree with Rezal... What type of overheating problems are you having?

A gt2 spoiler may be anohter option too.

roebedo

Speaking of cooling & spoilers.. I live in Arizona, and right now its been getting pretty warm.. actually pretty hot. I dont like to drive my car during the day, and I refuse to run the AC just because I feel better if I try and keep the car as cool as possible.

If I drive the car w/ the rear spoiler up at all times make any significant difference? It would almost seam to be true, because of the better air flow??

Nikoncamera

Hi, I'm really just looking to make the car a little more heat proof, with summer starting here soon ( Northern Australia gets pretty warm...), the engine temps are always on the warm side of cool, if you get my meaning.
I always have the engine cover off in summer, and have put in a oil fan bypass switch.Just thinking that a new Turbo S oil cooler is about $1000 AUD ( for about %20 more cooling ) and a CarGraphic is nearly $2000 AUD, I thought this might be a simple ,cheap mod to get slightly more efficient cooling, given that I dont think the car is overheating as such, just running " warm ".
Given our cars sensitivity to heat, and the constant heat, oil cooler and fan switching debates, why isnt this mod done as a simple first step ? Or is there a technical reason i'm missing?
Cheers Lyndon

chris walrod

By switching to a smaller pulley, you will reduce power output much like when the a/c compressor is on.. More oil cooling capacity is what you really need. Does your car run hot with the cooler fan on high all the time?

Nikoncamera

Hi Chris, the car just runs slightly warm in summer, nothing over the top.
I figured for a minimal power loss ( an extra 150 revolutions of fan for every 1000 revs) , that it would be better for the primary cooling system to be working slightly harder, rather than looking for expensive extra oil cooling, that is probably overkill for the driving conditions (ie The Car Graphic, as it seems to me that the Turbo S option only really works while the car is moving).
Cheers Lyndon

chris walrod

Also keep in mind that you dont want the fan to cavitate by spinning it too fast, as fans typically have a sweet spot in which a given blade design or profile has a best efficiency sweet spot. I will assume Porsche designed their fans sweet spot to run in the mean rpm range.. Not sure how efficient they are at redline?

I will bring this topic up with our aero guys..

mike cap

Lyndon,

You will see little if any benefit from a mod like this. Chris is correct, that the oil system is the primary heat transfer method by an overwhelming percentage.

A few years back I read a technical study on cooling of piston aircraft engines. I can't remember whether an engine manufacturer or airframe manufacturer did the study, but the engines are the same basic design as our cars - horizontally opposed, four and six cylinders, air-cooled.

The proper cooling of the engine in flight was attributable more (huge margin, like 80% - 20%) to the oil circulation in the engine and back through the oil cooler than to the air flow through the cowling and over the cylinder heads. Really surprised me when I read it.

I'll try and find that article. It was interesting reading.

Edit Note:
Also, one thing to keep in mind regarding running the cooling fan 15% faster is the fan or impeller "cube" rule. To drive the fan 15% faster will require about 50% more horsepower than is presently being consumed.

chris walrod

..yes, aero drag rules apply here as well

ljugete

Replacing your fog lights with the Turbo S scoop with fixed positioning light is a cheap but effective mod. IMHO.

Nikoncamera

thanks guys, cheers Lyndon

Greg Bell

Hi Lyndon,

I drive a 1996 C2 Coupe in Townsville North Queensland where it can get very hot. I've removed the engine tray and so far have had no issues with heat.