Plastic Engine Cooling Fan
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
Remember, a 993TT fan will not work in the 993 NA fan housing; you need the housing as well to do that.
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: May 2001
Posts: 8,365
Likes: 82
From: Vancouver, BC
I thought the fans were the same diameter between the NA and Turbo's and were interchangeable, and the difference in the shrouds were just because the Turbo needs the mounting spots for the IC. I did not know you cannot interchange the fans. Never compared them side by side, so good to know ...
Pro
Joined: Jun 2010
Posts: 537
Likes: 17
Originally Posted by Mike J
I thought the fans were the same diameter between the NA and Turbo's and were interchangeable, and the difference in the shrouds were just because the Turbo needs the mounting spots for the IC. I did not know you cannot interchange the fans. Never compared them side by side, so good to know ...
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Every Era of 911 Owner Explained in One Sentence
Verdad Gallardo
Thinking of Buying a Porsche? Do These 10 Things First
Joe Kucinski
Pixar Pals Turned Into 1-of-1 Porsches!
Michael S. Palmer
Theon Goes Full Carbon Fiber With Stunning New Build
Verdad Gallardo
Genius Porsche-Themed Gifts That'll Make Any Dad or Grad Smile
Joe Kucinski
10 Used Porsches Are Selling for Way Too Cheap
Joe Kucinski
Tuner Is Converting Porsche 911s Into Shooting Brakes
Verdad Gallardo
This Coachbuilt Creation Is A Modern Take on the Legendary Porsche 917
Verdad Gallardo
Is This Convertible Cayenne A Steal, Or A Returnless Investment?
Verdad Gallardo
RL Community Team
Rennlist Member
Rennlist Member
Joined: Jul 2004
Posts: 10,641
Likes: 2,057
From: Dallas, TX
I seem to recall the fans on Vintage Porsche racecars were plastic. I suspect the metal fan has to do with service life as a metal fan can last the life of the car and in racing it need only last the life of the race. I too have heard about fatigue failures of the fan. I suspect the root cause of these failures has more to do with fan contact to the housing due to a misalignment or a failing bearing. Manufacturers go to great lengths to test performance and service life of components. I am sure if the engineers could get long life out of plastic it would have been implemented as a quality/cost out project long before the 993. The fact that the fan is made of magnesium not zinc pot metal or other lower cost heavier metal casting suggests that Porsche engineers focused on this part quite a bit to keep the weight down.
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
I seem to recall the fans on Vintage Porsche racecars were plastic. I suspect the metal fan has to do with service life as a metal fan can last the life of the car and in racing it need only last the life of the race. I too have heard about fatigue failures of the fan. I suspect the root cause of these failures has more to do with fan contact to the housing due to a misalignment or a failing bearing. Manufacturers go to great lengths to test performance and service life of components. I am sure if the engineers could get long life out of plastic it would have been implemented as a quality/cost out project long before the 993. The fact that the fan is made of magnesium not zinc pot metal or other lower cost heavier metal casting suggests that Porsche engineers focused on this part quite a bit to keep the weight down.
Its simply FAR FAR more expensive to manufacture than a pressure casting.
RL Community Team
Rennlist Member
Rennlist Member
Joined: Jul 2004
Posts: 10,641
Likes: 2,057
From: Dallas, TX
Junk Science????
Uses three HP?? Seeing that the fan is spun up to speed when the car is running the use of HP is related to the pumping action of the fan not the acceleration of its mass to operating speed. Maybe we could gain three horsepower simply by removing the fan entirely? Then again the air intake tract would probably heat the air the engine uses quite a bit reducing combustion efficiency and output by a lot more than three horsepower! Then again 3 HP is just a guess in the first place according to the OP.