Welcome to the North American Subaru Impreza Owners Club Sunday April 20, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Electrical & Lighting

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 05-31-2005, 09:50 AM   #1
Valhakar
Scooby Specialist
 
Member#: 39514
Join Date: Jul 2003
Chapter/Region: SWIC
Location: Avondale, AZ
Vehicle:
2003 WRX 2.5L Hybrid
Mostly Blue

Default Anyone here built a FAN bypass switch for Radiator fans?

I am wanting to be able to turn the fans on manually to cool the engine in stop and go traffic. I also want to be able to hit a timed switch that will run them for X minutes after you turn off the engine.

My major concern is that ECU feedback. The ECU knows when the fans are running and the last thing I want is the car going into limp mode because the ECU thinks it is unable to turn on the fans.

Anyone?
* Registered users of the site do not see these ads.
Valhakar is offline   Reply With Quote
Old 05-31-2005, 10:23 AM   #2
cboggess
Scooby Specialist
 
Member#: 30804
Join Date: Dec 2002
Chapter/Region: SWIC
Vehicle:
87 Yugo
Red

Default

There's a company in australia that makes a fan cutoff switch for crossing deep rivers. I'd check with them to see if they make what you want. You can find them in the outback forum. They're the same company that makes the high clearance bumpers for the outback and forester.
cboggess is offline   Reply With Quote
Old 05-31-2005, 01:57 PM   #3
Undepelo
Scooby Specialist
 
Member#: 34960
Join Date: Apr 2003
Chapter/Region: MAIC
Location: MD
Vehicle:
What would baby
Jesus say of OT?

Default

Quote:
Originally Posted by Valhakar
I am wanting to be able to turn the fans on manually to cool the engine in stop and go traffic. I also want to be able to hit a timed switch that will run them for X minutes after you turn off the engine.

My major concern is that ECU feedback. The ECU knows when the fans are running and the last thing I want is the car going into limp mode because the ECU thinks it is unable to turn on the fans.

Anyone?
If everything is in working order, your engine will not keep much cooler even if you kept the fans on 24/7. For that you would have to remove the thermostat, which is not a good idea. The thermostat will regulate the coolant flow to the engine so if you cryofreez the radiator with 10Kcfm fans the termostat will just close and recirculate the coolant in the engine block. Keeping the engine in the range of operational temperature. Is your tamp. gauge going past normal?
Undepelo is offline   Reply With Quote
Old 05-31-2005, 02:06 PM   #4
Valhakar
Scooby Specialist
 
Member#: 39514
Join Date: Jul 2003
Chapter/Region: SWIC
Location: Avondale, AZ
Vehicle:
2003 WRX 2.5L Hybrid
Mostly Blue

Default

Quote:
Originally Posted by Undepelo
If everything is in working order, your engine will not keep much cooler even if you kept the fans on 24/7. For that you would have to remove the thermostat, which is not a good idea. The thermostat will regulate the coolant flow to the engine so if you cryofreez the radiator with 10Kcfm fans the termostat will just close and recirculate the coolant in the engine block. Keeping the engine in the range of operational temperature. Is your tamp. gauge going past normal?
1. Running a 160 degree thermostat.

2. It isn't just for the radiator. Fans cycle air through the engine bay helping to prevent heat soak. Heat soak that can make some cars rev to 2-3K on the tach till they get air moving through the engine bay to cool everything down. (No it cant be fixed, only affects a handful of people) I also run a skid plate.

3. Running fans while in the grid at AutoX or the strip is not only advisable, but a necessity.

4. Anyone with an oil temperature gauge knows the idiot gauge in the dash is only used by well........ idiots. I focus on my oil, not my coolant.

When your oil hits 110C++ because some D.C. Eurotrash trophy wife has wrapped her 70K SUV around a guard rail, you WANT the extra cooling. Also a cooling fan running for 5 minutes after you turn off the car cools down the oil in the turbo much better than a turbo timer.
Valhakar is offline   Reply With Quote
Old 05-31-2005, 02:19 PM   #5
Undepelo
Scooby Specialist
 
Member#: 34960
Join Date: Apr 2003
Chapter/Region: MAIC
Location: MD
Vehicle:
What would baby
Jesus say of OT?

Default

Quote:
Originally Posted by Valhakar
1. Running a 160 degree thermostat.

2. It isn't just for the radiator. Fans cycle air through the engine bay helping to prevent heat soak. Heat soak that can make some cars rev to 2-3K on the tach till they get air moving through the engine bay to cool everything down. (No it cant be fixed, only affects a handful of people) I also run a skid plate.

3. Running fans while in the grid at AutoX or the strip is not only advisable, but a necessity.

4. Anyone with an oil temperature gauge knows the idiot gauge in the dash is only used by well........ idiots. I focus on my oil, not my coolant.

When your oil hits 110C++ because some D.C. Eurotrash trophy wife has wrapped her 70K SUV around a guard rail, you WANT the extra cooling. Also a cooling fan running for 5 minutes after you turn off the car cools down the oil in the turbo much better than a turbo timer.
Ok, now we are talking.
Typically the thermo-switch that controls the fans are located at the base of the radiator. I haven't looked at the Impreza's etc. so it could be in a weird location. Anyway, They usually are 2 wire switches that close the circuit, duh.. which can be spliced and wired with a manual switch to bypass the thermo-switch. You can even make a harness between the thermo-switch and the feed wires so you don't have to cut into the OE wires. About the ECU, my guess is that if you feed the negative wire to ground via the manual switch and put a diode to avoid any reverse currents, your ECU has no way of knowing the fans are on.
Undepelo is offline   Reply With Quote
Old 05-31-2005, 02:27 PM   #6
Valhakar
Scooby Specialist
 
Member#: 39514
Join Date: Jul 2003
Chapter/Region: SWIC
Location: Avondale, AZ
Vehicle:
2003 WRX 2.5L Hybrid
Mostly Blue

Default

Sounds like a plan, once I find the switch. I am surprised no one else has done this. I haven't found a DIY anywhere.
Valhakar is offline   Reply With Quote
Old 05-31-2005, 03:04 PM   #7
Undepelo
Scooby Specialist
 
Member#: 34960
Join Date: Apr 2003
Chapter/Region: MAIC
Location: MD
Vehicle:
What would baby
Jesus say of OT?

Default

Quote:
Originally Posted by Valhakar
Sounds like a plan, once I find the switch. I am surprised no one else has done this. I haven't found a DIY anywhere.
Humm, I'm looking at the STi manual and don't see the thermo-switch.. I'll let you know if I find it.

I guess the other option is to use a relay and power the fans directly. If you do that you need to be sure you won't loose current when the car is off by using a ignition switched source of current only.

Last edited by Undepelo; 05-31-2005 at 03:12 PM.
Undepelo is offline   Reply With Quote
Old 05-31-2005, 03:39 PM   #8
Undepelo
Scooby Specialist
 
Member#: 34960
Join Date: Apr 2003
Chapter/Region: MAIC
Location: MD
Vehicle:
What would baby
Jesus say of OT?

Default

Well, I found the engine coolant temperature sensor, located near the manifold on a coolant line, but I don't think this is a switch, just a sensor. I think the fans may be turned on by the ECU and not mechanically. I wouldn't fool around with it. You would probably be safer to power the fans using a relay and a good current source.
Undepelo is offline   Reply With Quote
Old 05-31-2005, 04:01 PM   #9
mhaythor
Scooby Newbie
 
Member#: 82410
Join Date: Mar 2005
Chapter/Region: Tri-State
Location: Wilmington, DE
Vehicle:
2004 WRX

Default

Just press the air conditioner button to start the fans...

(ducking the ensuing onslaught)
mhaythor is offline   Reply With Quote
Old 05-31-2005, 04:03 PM   #10
Undepelo
Scooby Specialist
 
Member#: 34960
Join Date: Apr 2003
Chapter/Region: MAIC
Location: MD
Vehicle:
What would baby
Jesus say of OT?

Default

Quote:
Originally Posted by mhaythor
Just press the air conditioner button to start the fans...

(ducking the ensuing onslaught)
Undepelo is offline   Reply With Quote
Old 06-01-2005, 12:53 AM   #11
sabelt
Scooby Newbie
 
Member#: 39385
Join Date: Jul 2003
Default

ive used the PIVOT fan controller on my 03 sti... dont really like the results, using too much power, car feels sluggish duing hi revs...
sabelt is offline   Reply With Quote
Old 06-01-2005, 01:26 AM   #12
Rickyh
Scooby Specialist
 
Member#: 40453
Join Date: Jul 2003
Chapter/Region: South East
Location: Metairie, Louisiana
Default

HKS(or maybe Blitz) makes a fan controller. It can lower the setpoint that they turn on, you can manually turn em on, and a few other options. I've seen em for around 140 bux.
Rickyh is offline   Reply With Quote
Old 06-01-2005, 02:12 AM   #13
WRXBob
Scooby Specialist
 
Member#: 12455
Join Date: Nov 2001
Location: CA
Vehicle:
02 WRX

Default

You can fooled the ECU to turn on fan. Basically I grounded one of the fan relay wire by mean of a adj mechanical thermostat. I have been running that set up for over 3 years now.
WRXBob is offline   Reply With Quote
Old 06-01-2005, 09:14 AM   #14
Valhakar
Scooby Specialist
 
Member#: 39514
Join Date: Jul 2003
Chapter/Region: SWIC
Location: Avondale, AZ
Vehicle:
2003 WRX 2.5L Hybrid
Mostly Blue

Default

Quote:
Originally Posted by WRXBob
You can fooled the ECU to turn on fan. Basically I grounded one of the fan relay wire by mean of a adj mechanical thermostat. I have been running that set up for over 3 years now.
So the fan is always hot and uses a ground relay? ( One item I need to know )

You have bypassed the ECU relay and installed your own ground replay before it in the wire?
Valhakar is offline   Reply With Quote
Old 06-02-2005, 09:39 AM   #15
subieworx
Scooby Guru
 
Member#: 47769
Join Date: Nov 2003
Chapter/Region: MWSOC
Default

Quote:
Originally Posted by mhaythor
Just press the air conditioner button to start the fans...

(ducking the ensuing onslaught)
That's what I do.

My 91 Prelude I used to have would run the fans after the car was turned off. Thought something was wrong with the car at first.

Last edited by subieworx; 06-02-2005 at 10:39 AM.
subieworx is offline   Reply With Quote
Old 06-02-2005, 09:45 AM   #16
Valhakar
Scooby Specialist
 
Member#: 39514
Join Date: Jul 2003
Chapter/Region: SWIC
Location: Avondale, AZ
Vehicle:
2003 WRX 2.5L Hybrid
Mostly Blue

Default

You can't press the AC and walk away. Once I am able to tap the fans directly, I will build a timer to run after the car is turned off.
Valhakar is offline   Reply With Quote
Old 06-03-2005, 02:30 PM   #17
ride5000
Scooby Guru
 
Member#: 32792
Join Date: Feb 2003
Chapter/Region: NESIC
Location: lincoln, ri
Vehicle:
2003 GGA MBP
12.9 / 105+

Default

why on earth would you run the fan without coolant circulating?
ride5000 is online now   Reply With Quote
Old 06-05-2005, 12:10 AM   #18
Valhakar
Scooby Specialist
 
Member#: 39514
Join Date: Jul 2003
Chapter/Region: SWIC
Location: Avondale, AZ
Vehicle:
2003 WRX 2.5L Hybrid
Mostly Blue

Default

To cool the oil. As the oil cools it draws more from the turbo circulating oil. That is why our cars do not require a turbo timer. It also moves ait through the engine bay cooling everything down. You always run your fans with the engine off at the track between runs.
Valhakar is offline   Reply With Quote
Old 06-05-2005, 07:49 AM   #19
ride5000
Scooby Guru
 
Member#: 32792
Join Date: Feb 2003
Chapter/Region: NESIC
Location: lincoln, ri
Vehicle:
2003 GGA MBP
12.9 / 105+

Default

how does the fan pulling air through the radiator cool the oil?
ride5000 is online now   Reply With Quote
Old 06-05-2005, 08:05 AM   #20
Mulder
Trust no one
Moderator
 
Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 WRX
05 GTO/11 Sonata(!)

Default

There is no independent thermo-switch for the fans. The ECU turns them on and off based on data from the engine coolant temp sensor. You cannot tap that sensor for any external device because this will load the circuit and change the sensor value seen by the ECU, affecting engine operation. If you want to do this it has to be by controlling the fan relays, post-ECU.
Mulder is offline   Reply With Quote
Old 06-05-2005, 01:47 PM   #21
Valhakar
Scooby Specialist
 
Member#: 39514
Join Date: Jul 2003
Chapter/Region: SWIC
Location: Avondale, AZ
Vehicle:
2003 WRX 2.5L Hybrid
Mostly Blue

Default

Quote:
Originally Posted by ride5000
how does the fan pulling air through the radiator cool the oil?
The WRX has an oil cooler that sits up front. Moving air through the radiator pulls air through this as well.



As an example:



My engine oil temp gauge can be at 90C degrees. If I turn off the car and wait 5 minutes, the oil temperature is still at 85C ++. On the other hand if I turn off the engine then turn the ignition on, using the AC switch to turn on the fans, oil temperature drops into the 70C range in 3-5 minutes. The entire engine bay benefits as well. If you pop the hood with the fans off the IC, Intake, air box, heat shields and radiator are too hot to touch. Run the fans for 5 minutes and check, everything is warm.

I want the benefits of the cooling fans without having to sit outside in a hot car for 5 minutes. If I let the engine heat soak then start the car, driving into stop and go DC gridlock, the car does some really nasty things.
Valhakar is offline   Reply With Quote
Old 06-05-2005, 03:48 PM   #22
ride5000
Scooby Guru
 
Member#: 32792
Join Date: Feb 2003
Chapter/Region: NESIC
Location: lincoln, ri
Vehicle:
2003 GGA MBP
12.9 / 105+

Default

do you have a special wrx or something? aftermarket oil->air cooler?

in the oem case, we have an oil->water heat exchanger. coolant is PUMPED through the sandwitch adapter between the oil filter and the block. what pumps coolant is the water pump, which as an engine driven accessory does not circulate when the engine is not turning over.

on the flip side, the oil is pumped via the oil pump. this is another engine-driven accessory which will NOT circulate when the engine is not turning over.

so the normal method of oil to coolant heat exchange does NOT OCCUR when the engine isn't running.

when you see your oil temp drop with coolant fans on, remember that's the temp AT THE SENSOR. where is your oil temp sensor located?

blowing air over any hot object will indeed cool it off faster. to that end you will indeed return the entire engine block to ambient temps faster than if you do not have forced air flowing over/around it.

on the other hand, have you considered that the current draw of the radiator fans will be between 15 and 25 amps? that's a LOT of current to be drawing from a battery, which will eventually lead to an earlier demise.

i think you should be looking at installing fans on the IC, which is what you really want to keep cool in the first place.

jm2c
ken
ride5000 is online now   Reply With Quote
Old 06-06-2005, 09:03 AM   #23
Valhakar
Scooby Specialist
 
Member#: 39514
Join Date: Jul 2003
Chapter/Region: SWIC
Location: Avondale, AZ
Vehicle:
2003 WRX 2.5L Hybrid
Mostly Blue

Default

I could car less about the intercooler. My concern is cooling the entire engine bay to avoid an unwanted idle spike in heavy DC traffic.

By running the fans for 3-5 minutes I can lower the engine oil temperature by 15-20 degrees Celsius. Oil will circulate through the system as it cools. This is why the WRX does not require a turbo timer. Argue all you want about specs and systems, running the fans lowers the engine oil temperature, it is already proven by everyone that runs a oil temperature gauge.

I find that once my oil temperature gets above 95-100C and has sat for a few minutes, the engine tries to compensate by raising the idle to 1500-2000RPM+. My car is not the only one that does this and so far there is no cure so far for the dozen or so people I have met that have this issue. Car did it when stock, car does it now with aftermarket EM, 160 degree thermostat, and a 35/65 coolant/water ratio.

As for the battery concern, a battery is a consumable. I replace mine every 18 months. A few dollars spent every year and a half keeps the electrical system in peak performance.
Valhakar is offline   Reply With Quote
Old 06-06-2005, 09:25 AM   #24
ride5000
Scooby Guru
 
Member#: 32792
Join Date: Feb 2003
Chapter/Region: NESIC
Location: lincoln, ri
Vehicle:
2003 GGA MBP
12.9 / 105+

Default

if you think oil circulates when the engine is off, you've got a lot to learn about the mechanics of your car.

good luck.
ride5000 is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
WTB: motor for radiator fan!!!! aqua Private 'Wanted' Classifieds 2 10-01-2009 12:16 PM
IAT Switch For Intercooler Fan JSarv Water/Methanol Injection, Nitrous & Intercooler Cooling 19 07-06-2009 10:09 AM
installing manual switch for cooling fans? hybrid gti 2 Electrical & Lighting 3 05-07-2006 10:44 AM
Help: Anyone here with EDM's and leveler switch? 1stgearsyncro New England Impreza Club Forum -- NESIC 7 03-16-2004 01:55 PM
Anyone here that goes to Art Center for industrial/product design? codemunky Southern California Impreza Club Forum -- SCIC 12 04-23-2003 01:10 PM


All times are GMT -4. The time now is 06:35 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.