gristle101

The automotive industry didn't get very good with their plastics until the middle of the last decade. This opinion isn't hard to justify. Many of the plastic parts within our cars have discolored and become brittle with age. I have also driven a 2004 Land Rover and a 2003 Audi in the past with similar issues. Newer models don't yet appear to suffer from such issues.

This, in my opinion, is the reason why Porsche chose to make the engine cooling fan out of magnesium. The fan requires high blade tip stiffness at redline and must not shear, and also must have modestly good thermal cycle wear capability due to engine compartment temperatures. With these thoughts in mind, I believe that if the 911 air cooled motor were still being built today the fan would be made from a polymer based material.

As with any material, the magnesium does have some drawbacks. I have read in Paul Frere's Porsche 911 Story that the fan saps 3 hp from the motor. The blades have been known to sometimes become brittle with age and shear, causing damage in the engine compartment. They are also difficult to paint, according to a slew of Rennlist testimonies, due to surface wear from dust and dirt in the air as well as a narrow shroud clearance.

With this in mind, I have been daydreaming of a plastic replacement, made via an injection molding or 3D printing process. I don't think that the current form/shape of the fan would be difficult to adapt into a repeatable plastic type component. Then again, my background is in physics and engineering, not materials science. So at this point, my idea is just that--an idea--and nothing more.

There are a ton of businesses in the US that could potentially assist in designing and manufacturing this part, for example http://www.firstamericanplastic.com/ (no affiliation). In a perfect world, I would experiment to optimize the fan shape for increased airflow, but then again this isn't what I do professionally and I don't really have access to the equipment necessary for doing that. So instead I would hypothetically make a mold and/or a CAD rendering of the current magnesium fan and adapt it for manufacture out of a material that could satisfy the rigidity, durability, dimension spec/tolerance and thermal requirements. After that, the amount of interest from 911 owners would dictate the practicality of actually producing the plastic part.

So, I am asking anyone who will listen for insight. Do you think that this would be realistically possible? What do you think would be the biggest challenge? Would you be interested in buying one of these if they existed for maybe a couple hundred dollars?

AOW162435

Absolutely interested in where you take this. If you need a good fan for measurements/modeling, just shout. I may be able to help.



Andreas

gavonder

I would certainly be interested.

Holytin

Magnesium works perfectly fine for me. Why to replace? Where's the benefit? HP savings? You still have to cool this thing in the back of your car. Plastic also ages over the years so fatigue cannot be ruled out 100%

And I rather have a fan in the back of my 911 made from this very cool metal called MAGNESIUM! Who can still claim this nowadays?

I believe Porsche has done their homework back then. Unless its broke don't fix it...

Just my $.02. Time to open a beer...

KMASS993

I'm sure Robert Linton has looked into this. Probably worth reaching out to him to get his thoughts before proceeding.

AOW162435

http://www.fiberdynamics.net/index.html



Andreas

NYC993

Didn't some old racecars use plastic/fiberglass fans? That's what I recall seeing in the p-car museum.

NC TRACKRAT

At a current list price of $558 and discounted to $441, there would seem to be a great incentive to produce a less expensive alternative. NYC993, I think you're correct. I believe that the 917 used a plastic fan.

hapkido2

I'd love to see a carbon fiber version of the fan.

Steve Weiner-Rennsport Systems

A fan upgrade solution is underway and is superior to the OEM unit in several ways.

Not composite due to long-term durability issues; this one will be the very last fan you'll ever use.

_snowbird_

Suspense! Very curious to see where this goes (not that I actually need a fan).

nine9six

I couldnt help thinking this is probably because the newer models are not yet the age of the older models, right?

I think I'll take a page from the aircraft/aerospace industry and have a fan milled from billet titanium alloy, and be done with it! Being facetious of course

Race application fans have to last the duration of the race, not years; despite the enviornmental harshness of race applications.

OverBoosted28

This is like the Victoria Secrets model unbuttoning just the top few buttons of her shirt...........

AOW162435

Hanging on to your every word.




Andreas

Quadcammer

is there really a problem here?

The fans hardly ever catastophically fail and tend to show easily seeable issues prior to doing so (cracks at the base of blades). 3hp to cool the motor? I'm fine with that.

you can do whatever you like, but this seems like an awfully big waste of time and money.