|
|

|
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. |
|
|
| malaga_red75 |
Aug 6 2010, 05:52 PM
Post
#1
|
|
'74 2.5L N/A Subie ![]() ![]() Group: Members Posts: 454 Joined: 5-March 06 From: Menlo Park, CA Member No.: 5,674 Region Association: None |
subaru JDM EJ25 DOHC
So, got my conversion finally road worthy and have noticed that while I am driving around, the car stays at around 200 F. when i stop, or let it idle in my garage... the temp slowly climbs and doesnt stop (i shut it off around 230 F). I am assuming this is an issue with my fans. I am running a front mounted radiator, using 2 push-style fans. A few things that i think may be wrong... -There is no shroud around the fans... just the shroud that seals the radiator to the front (since they are push fans, they are mounted on the front side of the radiator, in between the radiator and the nose of the car) - there is about a 1 1/2" gap between the fans and the radiator (this was just the way that ended up working for mounting the fans) anyways, i am pretty sure that the cooling system is working (no kinked lines, thermostat working, fans do turn on) as indicated by driving and the temp staying cool, there is just something not working when i stop moving. let me know what you guys think. -Peter |
![]() ![]() |
| Mike Bellis |
Aug 6 2010, 07:03 PM
Post
#2
|
|
Resident Electrician ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 8,347 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None
|
First, you should pull the air not push. Second, i bet you have small pockets of air in your system. I would recommend you seal the system and pull a vacuum at the high point. This will force all the air to the vacuum.
When I do mine, I clamp off overflow tube on the expansion tank near the engine. Pull vacuum on the front for a few minutes. Take the overflow tube in the engine bay and put it in a bottle of water. Un-clamp the tube and the water will displace the air. Do this several times and all the air will be gone. Mine runs at 150-160 on the freeway, 180-190 stoped. |
| ArtechnikA |
Aug 6 2010, 08:07 PM
Post
#3
|
|
rich herzog ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 7,390 Joined: 4-April 03 From: Salted Roads, PA Member No.: 513 Region Association: None |
|
| Mike Bellis |
Aug 6 2010, 11:05 PM
Post
#4
|
|
Resident Electrician ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 8,347 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None
|
First, you should pull the air not push. Reference, please - 'cause everybody else in the world says it's easier to push a fluid than suck it... Air from any fan modulates. It may feel like just air blowing but as the blade cuts through the air, the air modulates. When you try to force air into a radiator, the surface design of the radiator will reflect the forced air molecules back on itself. This causes turbulence even before any air gets through the radiator. This action reduces the efficiency of the fan. Fans react more to output turbulance than input turbulance. The energy is the motion of air molecules moving in space. If I pull air from the back side of the radiator, there is no more turbulance than if I run the fan in free air. The efficiency of the fan increases. Air will be pulled through the radiator at a greater rate than if I try to push it. Have you ever tried to push a rope? |
malaga_red75 cooling issues... Aug 6 2010, 05:52 PM
BarberDave :trophy:
1st. Are you useing the same size rad... Aug 6 2010, 06:43 PM
ArtechnikA
Reference, please - 'cause everybody else in... Aug 7 2010, 06:18 AM
malaga_red75 Dave,
I do have a shroud that feeds all the air... Aug 6 2010, 08:00 PM
kg6dxn Fluid dynamics is different. Pushing or pulling fl... Aug 7 2010, 07:10 AM
ArtechnikA published reference... Aug 7 2010, 07:17 AM
DBCooper
published reference...
That's hard to do be... Aug 7 2010, 08:58 AM
kg6dxn
published reference...
I'm not sure what yo... Aug 10 2010, 10:57 PM
RobW Impressive technical knowledge... I want to drink ... Aug 7 2010, 07:20 AM
kg6dxn
Impressive technical knowledge... I want to drink... Aug 7 2010, 07:56 AM
malaga_red75 So, I re-did the cooling system, bringing the fans... Aug 10 2010, 10:37 PM
kg6dxn
So, I re-did the cooling system, bringing the fan... Aug 10 2010, 11:00 PM
malaga_red75
Looking at your picture, You may also want to c... Aug 10 2010, 11:39 PM
kg6dxn
Looking at your picture, You may also want to ... Aug 11 2010, 07:45 AM
kg6dxn I use a vacuum pump from harbor freight $70 a... Aug 10 2010, 10:53 PM
malaga_red75 ok, i will make my holes bigger then take some mea... Aug 11 2010, 12:28 PM
malaga_red75 So, yesterday I tried getting all the air out of t... Aug 12 2010, 10:12 AM
kg6dxn
So, yesterday I tried getting all the air out of ... Aug 12 2010, 11:36 AM
Phoenix-MN
So, yesterday I tried getting all the air out of... Aug 12 2010, 12:26 PM
malaga_red75
[quote name='kg6dxn' post='1355505' date='Aug 12 ... Aug 12 2010, 01:35 PM
malaga_red75 and mine will and does begin to overheat at idle i... Aug 12 2010, 01:36 PM
charliew You must not be moving enough coolant if you need ... Aug 12 2010, 05:20 PM
malaga_red75
You must not be moving enough coolant if you need... Aug 13 2010, 12:27 PM
ArtechnikA
Will a bad headgasket cause it to overheat at idl... Aug 13 2010, 03:15 PM
realred914 You could try the the Bong method to get the air ... Aug 13 2010, 11:22 PM
budman5201 I had the exact same problem in 2 of my sub conver... Aug 14 2010, 11:19 AM
malaga_red75
I had the exact same problem in 2 of my sub conve... Aug 14 2010, 12:02 PM
malaga_red75 well, new thermostat installed. no change... well... Aug 14 2010, 03:25 PM
kg6dxn
well, new thermostat installed. no change... wel... Aug 14 2010, 04:08 PM
budman5201 one question, how many return lines do you have th... Aug 14 2010, 04:56 PM
budman5201 the basic design of the water pump housing on a su... Aug 14 2010, 05:06 PM
malaga_red75 budman-
First, when i did the tstat test, the new... Aug 14 2010, 08:35 PM
budman5201
budman-
First, when i did the tstat test, the ne... Aug 15 2010, 12:56 PM
malaga_red75
budman-
First, when i did the tstat test, the n... Aug 15 2010, 03:42 PM
drive-ability IMO a blown head gasket would be much worse under ... Aug 14 2010, 09:44 PM
malaga_red75
IMO a blown head gasket would be much worse under... Aug 14 2010, 09:49 PM
budman5201 here is a stolen pic from STI progress thread. sho... Aug 15 2010, 01:31 PM
malaga_red75 well, I think (fingers crossed) that the cooling s... Aug 16 2010, 07:37 PM
kg6dxn Awesome! :Qarl: Now put that thing back togeth... Aug 16 2010, 07:45 PM
budman5201 SWEET! cool, anxious to see now where your tem... Aug 17 2010, 05:59 PM
malaga_red75 so, as the ultimate test for my cooling system, I ... Aug 19 2010, 11:41 AM
kg6dxn
so, as the ultimate test for my cooling system, I... Aug 19 2010, 11:45 AM
budman5201 SWEET! :headbanger: :driving: :DRUNK: Aug 19 2010, 06:18 PM
charliew I guess you also don't have the oil filter coo... Aug 20 2010, 11:30 AM
ArtechnikA
I guess you also don't have the oil filter co... Aug 20 2010, 12:22 PM![]() ![]() |
|
Lo-Fi Version | Time is now: 14th December 2025 - 12:08 PM |
| All rights reserved 914World.com © since 2002 |
|
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |