Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
> Cooling question - Fan housing vents
mikedsilva
post Jul 18 2015, 03:26 AM
Post #1


Member
**

Group: Members
Posts: 90
Joined: 23-February 15
From: Australia
Member No.: 18,462
Region Association: Australia and New Zealand



I live in quite a warm climate, and my car has the stock heat exchangers, but the heating system is not connected and I don't have the motor installed to pump warm air to the cabin anyway.

My question is whether I would benefit by blocking off the 2 vents from the fan housing, that blow air through the heat exchangers?
Would this help force more cooling air through the fins of the motor?

Here is a pic of one of the fan housing vents I am referring to...
(IMG:http://www.914world.com/bbs2/uploads_offsite/i1260.photobucket.com-18462-1437211603.1.jpg)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
barefoot
post Jul 18 2015, 06:18 AM
Post #2


Senior Member
***

Group: Members
Posts: 1,279
Joined: 19-March 13
From: Charleston SC
Member No.: 15,673
Region Association: South East States



Yes, blocking them off will force more air thru the cylinders.When I got mine, it had these capped off by some aluminum bits fabed from an old license plate and worm drive hose clamps.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mikedsilva
post Jul 18 2015, 06:26 AM
Post #3


Member
**

Group: Members
Posts: 90
Joined: 23-February 15
From: Australia
Member No.: 18,462
Region Association: Australia and New Zealand



excellent.
Thanks for the reply!
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dave_Darling
post Jul 18 2015, 11:57 AM
Post #4


914 Idiot
**********

Group: Members
Posts: 14,991
Joined: 9-January 03
From: Silicon Valley / Kailua-Kona
Member No.: 121
Region Association: Northern California



Air flow is tricky stuff. It doesn't always do what it looks like it should.

In this particular case, we have at least one person with instrumentation (Jake Raby) who tells us that blocking those off leads to increased head temperatures. I don't know the mechanism, but is seems like the setup wants to bleed air off through those.

--DD
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
ThePaintedMan
post Jul 18 2015, 12:53 PM
Post #5


Advanced Member
****

Group: Members
Posts: 3,886
Joined: 6-September 11
From: St. Petersburg, FL
Member No.: 13,527
Region Association: South East States



(IMG:style_emoticons/default/agree.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mikedsilva
post Jul 18 2015, 02:46 PM
Post #6


Member
**

Group: Members
Posts: 90
Joined: 23-February 15
From: Australia
Member No.: 18,462
Region Association: Australia and New Zealand



oh.. now i am confused.. I too thought i read somewhere that blocking off is not good.
But even if the tubes and heater fan were all connected, if the heater was turned off and the air had nowhere to go, isnt that the same as blocking the exits?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
vw505
post Jul 18 2015, 03:08 PM
Post #7


Member
**

Group: Members
Posts: 228
Joined: 17-April 03
From: San Antonio, TX , Navy retired
Member No.: 579
Region Association: None



No the air get dumped after going though the exchangers, so it bleeds a small amount of air at all times. Think of how hot the heat exchangers would get if the bleed air didn't flow through them.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
era vulgaris
post Jul 18 2015, 04:31 PM
Post #8


J is for Genius
***

Group: Members
Posts: 982
Joined: 10-November 13
From: Raleigh, NC
Member No.: 16,629
Region Association: South East States



QUOTE(mikedsilva @ Jul 18 2015, 04:46 PM) *

oh.. now i am confused.. I too thought i read somewhere that blocking off is not good.
But even if the tubes and heater fan were all connected, if the heater was turned off and the air had nowhere to go, isnt that the same as blocking the exits?


The air does have somewhere to go. Have you ever looked at a flapper valve? When closed to the cabin, the air that's passed through the heat exchangers simply gets routed out to the ambient air under the car.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mikedsilva
post Jul 18 2015, 05:49 PM
Post #9


Member
**

Group: Members
Posts: 90
Joined: 23-February 15
From: Australia
Member No.: 18,462
Region Association: Australia and New Zealand



ok
I am convinced now, that I should NOT block off the vents to the fan housing and that they should be left to run through the heat exchangers...
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Spoke
post Jul 19 2015, 05:15 AM
Post #10


Jerry
*****

Group: Members
Posts: 6,986
Joined: 29-October 04
From: Allentown, PA
Member No.: 3,031
Region Association: None



QUOTE(mikedsilva @ Jul 18 2015, 07:49 PM) *

ok
I am convinced now, that I should NOT block off the vents to the fan housing and that they should be left to run through the heat exchangers...


If you have heat exchangers you should run the air through them. As mentioned, the airflow through the HE's never stops. For cabin heating, the air is directed to the interior by the flapper. If no cabin heat is required, the air is dump out under the engine at the heat flapper.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 30th May 2024 - 03:23 PM