MVRK - DIY - Electric Fan Conversion

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mvrk10256
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MVRK - DIY - Electric Fan Conversion

Postby mvrk10256 » Wed Nov 30, 2011 5:40 pm

DISCLAIMER: I AM NOT RESPONSIBLE FOR ANYTHING IF YOU FUCK IT UP.

otherwise feel free to ask me questions.


DIY: Electric Fan Conversion

Parts:
1.Spal 16" fan
2. Spal fan mount kit
3. BimmerWorld Spal Fan Harness

[COLOR="red"]NOTE1: This project involved messing with your cars electrical system. If you don't understand the terms, or whats going on in this post I strongly recommend you do not attempt this on your own as it requires some electrical knowhow. [/COLOR]

NOTE2: Due to the thermo switch being voltage activated whereas the kit is ground activated we are going to make modifications to the original design, they will be clearly and explicitly explained in this post.

NOTE3: The way we are wiring it we have to have the blue AC button on for the fans to go on, but it is totally worth it.


DIY:
1. Pull out the original fan
-32mm wrench
-reverse threaded
Image

2. Bolt it in
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3. The Harness you get has 4 wires and a relay.
-Red : Fan positive
-Yellow: 12V battery
-orange: ignition
-grey: sending unit

here is the original schematic:
Image

here is the modified one:

Image

***The reason we are doing this is because the thermo switch is 12V activated, meaning it turns stuff on with applying a 12V signal to the device.The fan system is designed to be ground activated - meaning there is a continuous 12V signal and we open a ground connection to activate.

This makes us have a slight dilemma. We solve it by switching our system and making it 12V activated. Since the relay basically has two chanels we are now going to make the "ignition" wire (orange) always go to ground, and the grey wire will now get a 12V signal at activation.

Now that we understand whats going on lets start wiring

4. Get access to 12V battery ( this is a good time to get access to the 12V switched (ignition as well) but we wont need ignition for this.

*This thing is the best place to tap in as it doesnt really do anything anyway.
Image

RED: 12V
Green: Switched

5.(OPTIONAL) Since I will need 12V for other projects I made a Y connectors
Image
Dont forget to put the 20A fuse inline
Image
Image

and in the car
Image

6. Make a ground
-I used one of the existing holes for a ground - just make sure you clean off the paint and you have a good contact
-we will run the fan ground and the orange "ignition" wire there as well
Image

7. Mount the relay here next to air filter
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8. Red wire run from the 12V to the yellow wire to the relay
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9. connect the red wire from the fan to the red wire on the relay
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10.our wire bundle
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at this point you should have:

RED(relay) to RED(fan +12)
BLACK(fan) to ground
ORANGE(relay) to ground
YELLOW(relay) to +12V on car


that only leaves the grey wire to hook up.

11. Run the grey wire across teh front of the car
Image

-I put holes in the metal and used zip ties to run it along the inside between radiator and frame.

12. Time to wire it into the Thermo Sensor

*There are multiple versions of this plug. use a voltmeter to figure out what lines you need to tap into. Basically one of the three plugs will have a 12V signal when you hook it to ground (middle one (green/black) on mine)

the other two wires are the slow and fast ones this is what we will tap into.

NOTE: when you reach 119C it switches to fast - BUT IT TURNS OFF SLOW! - so we have to tap into both.

Image


13. at this point just clean up the wires and get everthing put back together.

AGAIN REMEMBER YOU NEED TO HIT THE BLUE AC BUTTON FOR IT TO TURN ON!!.


Alternatively you can just wire it to the igition as I did in the end, so the fan spins whenever the ignition is on. keeps car cool and works nice at the track.
Last edited by mvrk10256 on Wed Nov 30, 2011 6:22 pm, edited 1 time in total.
-Maksim

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M20_fever
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Re: MVRK - DIY - Electric Fan Conversion

Postby M20_fever » Wed Nov 30, 2011 5:56 pm

this is exactly how I wired mine in, works great.
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mvrk10256
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Re: MVRK - DIY - Electric Fan Conversion

Postby mvrk10256 » Tue Dec 06, 2011 4:58 am

M20_fever wrote:this is exactly how I wired mine in, works great.



I ended up wired to ignition. Keeps me cool on the track between laps.
-Maksim

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Re: MVRK - DIY - Electric Fan Conversion

Postby M20_fever » Tue Dec 06, 2011 1:09 pm

I deleted the ac, so the button just stays on, so the fan runs with ignition anyway.
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Re: MVRK - DIY - Electric Fan Conversion

Postby Rick » Thu Dec 08, 2011 7:00 pm

Have you driven with this mod in our southwest summer yet?

May have to do this, I hate the fan sound when its hot out and you rev the engine, sounds like a Cessna lol. Must be good for a HP or two as well (at least when the elec fan is off anyway)
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Re: MVRK - DIY - Electric Fan Conversion

Postby M20_fever » Thu Dec 08, 2011 7:30 pm

Its been fine on 100+ track days, and in moderate traffic on chicago summers.
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Re: MVRK - DIY - Electric Fan Conversion

Postby mvrk10256 » Thu Dec 08, 2011 10:26 pm

Rick wrote:Have you driven with this mod in our southwest summer yet?

May have to do this, I hate the fan sound when its hot out and you rev the engine, sounds like a Cessna lol. Must be good for a HP or two as well (at least when the elec fan is off anyway)



Ya it is actually slightly cooler on the M20 than my stock fan. I did this last summer actually. I noticed it spins up a little better but that may a plecebo effect.



M20_fever wrote:Its been fine on 100+ track days, and in moderate traffic on chicago summers.

+ 1 stood in traffic for like 30 minutes idleing no issue.
-Maksim

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Re: MVRK - DIY - Electric Fan Conversion

Postby Rick » Fri Dec 09, 2011 2:25 am

Excellent, will do then. -yuush-
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Re: MVRK - DIY - Electric Fan Conversion

Postby Rick » Fri Dec 09, 2011 2:34 am

BTW to have it run all the time is a waste (if you're doing that). The alternator is ~80% efficient, and the fan motor is prob 75%, so in reality you are using more power from the engine via the alternator than turning the mechanical fan.

Splitting atoms but WTF, power is power.
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mvrk10256
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Re: MVRK - DIY - Electric Fan Conversion

Postby mvrk10256 » Fri Dec 09, 2011 2:43 am

Rick wrote:BTW to have it run all the time is a waste (if you're doing that). The alternator is ~80% efficient, and the fan motor is prob 75%, so in reality you are using more power from the engine via the alternator than turning the mechanical fan.

Splitting atoms but WTF, power is power.



It runs when the engine is on. At worst it is as bad as mechanical fan, but it moves much more air and is very useful. Sounds like the best solution is fuck fans. Just drive faster.
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Re: MVRK - DIY - Electric Fan Conversion

Postby Rick » Fri Dec 09, 2011 2:59 am

LOL, problem is other assholes are on the road and jam you up -angry-

IMHO unless you turn that puppy off, you havent saved a thing.
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mvrk10256
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Re: MVRK - DIY - Electric Fan Conversion

Postby mvrk10256 » Fri Dec 09, 2011 5:36 am

Rick wrote:LOL, problem is other assholes are on the road and jam you up -angry-

IMHO unless you turn that puppy off, you havent saved a thing.



I mean alternator is spinning one way or another. It keeps the engine cooler. Better efficiency. Peace of mind. No issues with 20lbs battery. Worth it for me
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Re: MVRK - DIY - Electric Fan Conversion

Postby Rick » Fri Dec 09, 2011 9:59 pm

Do you know many amps your fan draws?
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Re: MVRK - DIY - Electric Fan Conversion

Postby mvrk10256 » Fri Dec 09, 2011 11:12 pm

Rick wrote:Do you know many amps your fan draws?



Currently have a 20A fuse in there and no issues so less than that.

How much exactly I dont know.
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Re: MVRK - DIY - Electric Fan Conversion

Postby Rick » Sat Dec 10, 2011 1:47 am

Was curious so calced it. Probably 12-15 amps. lets say 15.
It takes roughly 2/3 hp from the engine via the alternator to run the fan. Not much :)

Where did you get yours?
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