Transmission Fan Wiring and Cooler Installation

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
Since my car is up on jackstands I figured I'd upgrade my transmission cooler. Previously I had been running a converted PPKv2 radiator as a cooler. I do not recommend it because you'll experience runaway temps, that core is no match for the stock system. I've dealt with it for a long time because I have not driven my car much but now I've decided to take some action.

I started by sourcing a 'Small' dual pass cooler from Mishimoto then upgraded to the Large then went to a Setrab 72 row but in the end I decided to go back to an ebay dual pass that is virtually identical to the Mishimoto unit. I bought these coolers on sale in December 2018 and they have just sat in my garage and upon looking just now, it appears they are half off the half-off price I paid before, just under $60 a pop:

This cooler isn't a world beater but it does fit the given space with convenient side outlets unlike pretty much any other cooler I could find. Since this is not a race car and I don't like the look of deleted ducting, my constraint was an oem fitment and that meant retaining the fog lights, brake ducts and headlight washers. Ideally, I'd be able to retrofit my existing PPK duct with this new setup.

After testing fitment(and waiting a year) I pulled off the frame rail support bracket and hammered it flat. The OEM bracket comes in at an odd angle and means the task of bending metal to fit had become no longer a DIY at home sort of job. Since I don't have a welder I would have to stick to more rudimentary means to make this work.

This is what the bracket looks like before:
31057


Used a dremel to cut off the welded bolts:
31058


Take a heavy hammer and flatten it out to make a nice mounting surface. This picture below was not the final angle, but you'll want it to be pretty close to the frame rail when done with a slight angle forward about halfway through so the cooler fits inside the fender liner.
31059


Next, I went an grabbed some aluminum flatbar from Home depot and hammered out a simple bracket:
31060


Additionally I bought:
2x 10AN to 8AN 90 degree hose ends (Fragola 229009)
6x 8AN hose ends (Russell 610035)
10 FT 8AN Nylon hose (Amazon)
5.2" Paddle Blade Pusher Fan (Spal 30103013) (VA31-A101-46S)
180 Degree Farenheit fan kit (Derale 16720)
8AN adapter with 1/8 NPT Sensor port (Russell 670353)

It is also assumed you've purchased or already have the 8AN transmission fittings and the Improved Racing 160 degree thermostat with 8AN fitment.

When mounted it will look something like this:
31061

31062

31063

31066



I did start to mock up the OEM bracket since I already had it but this metal is not good for bending and broke so a custom bracket will need to be made later:
31064



I decided to mount the thermostat below the brake duct since there is a circular flat spot on the fender liner(MSport) that it should be able to mount to pretty easily. This is the position it will have:
31067
31068


Be sure to run the outlet to the top cooler port. If you go back to the transmission, the 'outlet' is on top, per realoem diagrams.
31070
31074


Now I mounted up the thermoswitch:
31071
31072


And here we are a few zipties later:
31073



WIRING:

31084

Per the chart above, I think that says the fan will draw 4-6 amps at 13v since I have the pusher fan. The pusher fan part number ends with "S" and not "A" so I am guessing that means Soffiante vs Aspirante. Makes me wonder if the motor is actually different or if the propeller angles are just optimized for one direction or another. In any case, we will need 22-23 gauge power wires.

This estimate is based on nick-free soft annealed Cu wire having a tensile strength of 37000 pounds per square inch.

AWG gaugeConductor
Diameter Inches
Conductor
Diameter mm
Conductor cross section in mm2Ohms per 1000 ft.Ohms per kmMaximum amps for chassis wiringMaximum amps for
power transmission
Maximum frequency for
100% skin depth for solid conductor copper
Breaking force Soft Annealed Cu 37000 PSI
00000.4611.6841070.0490.16072380302125 Hz6120 lbs
0000.409610.4038484.90.06180.202704328239160 Hz4860 lbs
000.36489.2659267.40.07790.255512283190200 Hz3860 lbs
00.32498.2524653.50.09830.322424245150250 Hz3060 lbs
10.28937.3482242.40.12390.406392211119325 Hz2430 lbs
20.25766.5430433.60.15630.51266418194410 Hz1930 lbs
30.22945.8267626.70.1970.6461615875500 Hz1530 lbs
40.20435.1892221.10.24850.8150813560650 Hz1210 lbs
50.18194.6202616.80.31331.02762411847810 Hz960 lbs
60.1624.114813.30.39511.295928101371100 Hz760 lbs
70.14433.6652210.60.49821.63409689301300 Hz605 lbs
80.12853.26398.370.62822.06049673241650 Hz480 lbs
90.11442.905766.630.79212.59808864192050 Hz380 lbs
100.10192.588265.260.99893.27639255152600 Hz314 lbs
110.09072.303784.171.264.132847123200 Hz249 lbs
120.08082.052323.311.5885.20864419.34150 Hz197 lbs
130.0721.82882.632.0036.56984357.45300 Hz150 lbs
140.06411.628142.082.5258.282325.96700 Hz119 lbs
150.05711.450341.653.18410.44352284.78250 Hz94 lbs
160.05081.290321.314.01613.17248223.711 k Hz75 lbs
170.04531.150621.045.06416.60992192.913 k Hz59 lbs
180.04031.023620.8236.38520.9428162.317 kHz47 lbs
190.03590.911860.6538.05126.40728141.821 kHz37 lbs
200.0320.81280.51910.1533.292111.527 kHz29 lbs
210.02850.72390.41212.841.98491.233 kHz23 lbs
220.02530.645160.32716.1452.939270.9242 kHz18 lbs
230.02260.574040.25920.3666.78084.70.72953 kHz14.5 lbs
240.02010.510540.20525.6784.19763.50.57768 kHz11.5 lbs
250.01790.454660.16232.37106.17362.70.45785 kHz9 lbs
260.01590.403860.12840.81133.85682.20.361107 kHz7.2 lbs
270.01420.360680.10251.47168.82161.70.288130 kHz5.5 lbs
280.01260.320040.08064.9212.8721.40.226170 kHz4.5 lbs
290.01130.287020.064781.83268.40241.20.182210 kHz3.6 lbs
300.010.2540.0507103.2338.4960.860.142270 kHz2.75 lbs
310.00890.226060.0401130.1426.7280.70.113340 kHz2.25 lbs
320.0080.20320.0324164.1538.2480.530.091430 kHz1.8 lbs
Metric 2.00.007870.2000.0314169.39555.610.510.088440 kHz
330.00710.180340.0255206.9678.6320.430.072540 kHz1.3 lbs
Metric 1.80.007090.1800.0254207.5680.550.430.072540 kHz
340.00630.160020.0201260.9855.7520.330.056690 kHz1.1 lbs
Metric 1.60.00630.160020.0201260.9855.7520.330.056690 kHz
350.00560.142240.01593291079.120.270.044870 kHz0.92 lbs
Metric 1.4.00551.1400.015433911140.260.043900 kHz
360.0050.1270.0127414.813600.210.0351100 kHz0.72 lbs
Metric 1.25.004920.1250.0123428.214040.200.0341150 kHz
370.00450.11430.0103523.117150.170.02891350 kHz0.57 lbs
Metric 1.12.004410.1120.00985533.817500.1630.02771400 kHz
380.0040.10160.00811659.621630.130.02281750 kHz0.45 lbs
Metric 1.003940.10000.00785670.221980.1260.02251750 kHz
390.00350.08890.00621831.827280.110.01752250 kHz0.36 lbs
400.00310.078740.00487104934400.090.01372900 kHz0.29 lbs

Below are the specs of the fan, on the graph it is the red line, VA31-A101-46S:
31056
31052


It uses connector SUMITOMO Code 6010-2802, terminal code 1800-2093.

The female connector we need is 6110-4623 with terminal 1800-2094. You can find in various places including Amazon but I ended up ordering from https://www.corsa-technic.com since they provide the contacts with the housing in addition to listed documentation and a decent price. Truth be told, you should just depin/cut/splice but I'm weird.

FYI, regular female terminals actually fit inside of this connector so I'll be doing this temporarily until the actual connector shows up:
31081
31082



Possible Wires of interest:

B3Xa are the front PDC sensors but only have access to 5 amps if I am reading the diagrams correctly(probably not). E26 is the left fog light which is interesting as a manual switch. E126 is the left headlight. B42b (not shown) is the ride height sensor but I'm unsure if there is usable power
B43a TPM RDC Transmitter is also in this area, but the wire gauge is small.

31026
31027



Headlight:

This seems to be what people first gravitate to.
31020

31021

31023

31031

31032

ConnectorPinDescriptionColor
X134201Grey / Brown Stripe??
2GroundBrown
3Signal, low beamYellow /Green StripeLeft headlight
4GroundBrown
5Activation, bi-xenon shuttersBrown/ Yellow StripeLeft headlight Right headlight
6Signal, high beamWhite / Green StripeLeft headlight
7Signal, parking lightBlack / Green StripeLeft headlight
8Signal, headlight vertical aim controlYellow / Red StripeLeft headlight
9Supply, stepper motorsYellow / Brown StripeLeft headlight Right headlight
10Signal, LIN busBlue / Red StripeLeft headlight
11Signal, headlight vertical aim controlBlue / Brown StripeLeft headlight
12Signal, front left direction indicatorBlue / Green StripeLeft headlight


What I don't like about these wires is primarily the gauge thickness. All of these wires appear to be aprox 27 gauge


=======================


Foglight:
31022


ConnectorPinDescriptionColor
X7681GroundBrown
X7682Signal, fog lightYellow / Brown StripeLeft fog light

==========================


Ride height Sensor:
31028

31024

31025


ConnectorPinDescriptionColorConnector
X180321Ground Ride height sensor, frontGrey / White StripeRide height sensor, front
2
3
X180324Signal, front level sensorGrey / Green StripeRide height sensor, front
X180325Supply, level sensorGrey / Brown StripeRide height sensor, front


TPM RDC Transmitter:
Power wire seems thin so it may be able to act as a switched trigger wire.

For anyone unfamiliar with the bi-directional wheel electronics (not everyone has it):
31078
31077



They are mounted on the fender liners. I had to move their mountijng point because I put the cooler exhaust vent here:
31079

31076

31080

ConnectorPinColorSignal TypeDescription
X180401Brown / Yellow StripeRDC_VL-Ground
X180402Black / Yellow StripeRDC_VL+Positive supply RDS transmitter, front left
X180403Grey / Yellow StripeRDC_BUSSignal, RDC receive antenna
======


===

So it looks like I'll be looking for:

Yellow with Brown stripe fog light override
Black with Green Stripe headlight remote wire for thermoswitch
Dedicated 12v battery wire[/SPOILER]
 

Attachments

  • 03013_SPEC.pdf
    459.3 KB · Views: 42
  • Derale.pdf
    441.9 KB · Views: 31
Last edited:

matreyia

Major
Apr 19, 2017
1,780
711
0
Ride
335i e93
I used headlight, left. and I leave it on permanently since it turns off when engine is shut off. Add red wire to constant ON connection with inline fuse.
 

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
I used headlight, left. and I leave it on permanently since it turns off when engine is shut off. Add red wire to constant ON connection with inline fuse.
Based on my latest documentation of the RDC Transmitter, I am hoping to find a positive remote wire on Pin 2. Then I'll likely run a dedicated wire to the battery post using a proper gauge power wire. The only power wire I've seen so far that looks sufficient is the fog light and I intend to use it as a manual thermoswitch over-ride instead. The parking/daytime lights wire you are using is only 0.5mm which shouldn't be used for more than 3.7 amps per the chart I listed above. I don't know how many amps your fan uses but mine could see as many as 5.8+ if the fan were to get stuck or seize somehow and go under load.
 

matreyia

Major
Apr 19, 2017
1,780
711
0
Ride
335i e93
Based on my latest documentation of the RDC Transmitter, I am hoping to find a positive remote wire on Pin 2. Then I'll likely run a dedicated wire to the battery post using a proper gauge power wire. The only power wire I've seen so far that looks sufficient is the fog light and I intend to use it as a manual thermoswitch over-ride instead. The parking/daytime lights wire you are using is only 0.5mm which shouldn't be used for more than 3.7 amps per the chart I listed above. I don't know how many amps your fan uses but mine could see as many as 5.8+ if the fan were to get stuck or seize somehow and go under load.

I run two fans off the headlight and never had any problem. Not daytime lights...headlights you must turn on to activate fans when temps are reached.
 

iminhell1

Sergeant
Jun 17, 2018
419
206
0
Based on my latest documentation of the RDC Transmitter, I am hoping to find a positive remote wire on Pin 2. Then I'll likely run a dedicated wire to the battery post using a proper gauge power wire. The only power wire I've seen so far that looks sufficient is the fog light and I intend to use it as a manual thermoswitch over-ride instead. The parking/daytime lights wire you are using is only 0.5mm which shouldn't be used for more than 3.7 amps per the chart I listed above. I don't know how many amps your fan uses but mine could see as many as 5.8+ if the fan were to get stuck or seize somehow and go under load.


If you're using a relay (which you should be), the trigger wire size won't matter ...
 

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
If you're using a relay (which you should be), the trigger wire size won't matter ...

Right, I was trying to avoid running a dedicated power wire. None of them are sufficient besides the xenon and fog lights. Both of which are poor choices as they must be switched on or depend on the sunlight sensor.

The remote wire was a different topic, also I thought he was using a switchable wire as his main power source. Which he is but he's cleared that up as well.
 

iminhell1

Sergeant
Jun 17, 2018
419
206
0
Suggestion for switch, the help call button in the overhead. It's not good for anything else.
 

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
Finished the install today.

The RDC Transmitter lines have varying voltages so they won't work. There is no front PDC on this car but even if there was I suspect the wires are only energized when needed. So I tapped the Parking light wire for a remote source then wrapped it with black tape so it looks part of the loom:
20190920_191308.jpg20190920_192910.jpg

I ran a dedicated 12v source from the battery post terminal up the passenger side, across the radiator carrier, up the driver fender then followed the existing head light harness down to an inline 30a fuse and then to the thermoswitch:
20190920_201722.jpg

The other thermoswitch wire goes to the relay. I also hooked the fog light wire to the relay as a secondary activation method.

Then I used black tape and cleaned up the rats nest of resulting wires:
20190921_164102.jpg

20190921_173720.jpg

Put it back together:
20190921_191329.jpg

I need a duct still:
20190921_194335.jpg20190921_194352.jpg
 

Jeffman

Major
Jan 7, 2017
1,618
1
628
0
Your transmission radiator cooler and fan setup looks great, Tyler.
But your last photo showing the thermoswitch wiring sticking up inside the fog light grill concerns me just a little. It looks somewhat vulnerable to rock bits, sand, and water etc. You may want to wrap it up as well with a suitable weather-resistant rubbery adhesive tape.
 
  • Like
Reactions: doublespaces

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
Your transmission radiator cooler and fan setup looks great, Tyler.
But your last photo showing the thermoswitch wiring sticking up inside the fog light grill concerns me just a little. It looks somewhat vulnerable to rock bits, sand, and water etc. You may want to wrap it up as well with a suitable weather-resistant rubbery adhesive tape.

It hurts me on the visual factor as well. The idea is to re-use part of my existing duct and combine it with some aluminum/sheet metal to ensure the fan is blowing through the fins.

Speaking of the thermoswitch, it never activated so I'll have to double check that I've got it wired correctly. Touching a wire to both of the thermoswitch's pins activates the fan, so the circuit is just not activating at 180 like it's supposed to even at 200 degrees. So after a bit of driving I went and found a parking lot and idled there for some time with the fan enabled. The cooling isn't quick and I'm going to need some ducting/shroud to ensure the fan is blowing air through the fins and not around the side.

Here is 'proof' at a minimum it can stave off 91 degree ambient temps while parked. It started at 198, went up to 199 and fell down to 194. This took quite some time actually but at least I can park the car and not worry about the temps rising continuously.
31199


I'll work on the efficiency of the setup and also test how it performs without the fan on open-road. Theres multiple things I would like to do to improve it's performance but at least it works, more than I can say about my last setup.
 

Stokes

Sergeant
Jan 26, 2018
264
156
0
Houston, TX
Ride
2011 BMW 135i
@doublespaces couple questions...

1. Are you DCT?
2. Did you remove the factory cooler (not use it in conjunction with the dedicated one in the wheel well) and is that why the fan is required?

I'm looking to reduce DCT Temps on track days and it looks like the non M cars utilize the same setup for dct and auto.
 

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
@doublespaces couple questions...

1. Are you DCT?
Not yet, still 6AT

2. Did you remove the factory cooler (not use it in conjunction with the dedicated one in the wheel well) and is that why the fan is required?

I'm looking to reduce DCT Temps on track days and it looks like the non M cars utilize the same setup for dct and auto.

I have a 6MT CSF radiator and 6MT heater core return pipe (Plastic thing that runs across the subframe) and 6MT coolant fittings for my ADE ST kit. The old transmission cooling system is completely deleted, nothing vestigial.
 
  • Like
Reactions: Stokes

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
The connectors came in the mail:

31454


I also went back in and cinched down the thermal switch as I felt a little bit of oil on the bottom of the fittings. The switch is supposed activate at 180F however in my previous outing it never turned on by the time 199F rolled around so I figured seating it down further should help it give a more accurate reading:

31455


I had a photo of the fan connector all hooked up, however it has managed to disappear although it looks as you can imagine. Fits well.

I needed to burn off some fuel to make working in the tank easier so I went on a cruise and got a chance to do some testing of the cooling system in what my car reported as 91F ambient temps. On the freeway cruising around 70 MPH the cooler works fairly well and cooled the transmission fluid down to 76F without any ducting. The thermostat cracks at 160F and is fully open at 180F so I'm very happy with the result. I'm sure the temps could drop faster with proper ducts despite running into traffic once, here is a graph:

31459


I also did some surface street stop light driving and this time the fan did kick on at about 200F when I was pulling into a drive through and it was off again by the time I got home. I think the trigger point was around 198-200F, which will vary for you depending on installation. While parked without airflow it is capable of halting the temperature from creeping up and it will slowly turn the temps back down.

When I was parking back in my garage it had turned back on and there was quite a lot of very hot air coming from my wheel well. I grabbed a temp gun and a napkin to give an idea of how much hot air was being pushed out:

 
Last edited:
  • Like
Reactions: seb.apprenti

Jeffman

Major
Jan 7, 2017
1,618
1
628
0
Looks like you nailed it, Tyler. Is 176F while cruising your goal?
(And just wondering out loud what is an ideal transmission fluid temp?)
 
Last edited:

doublespaces

Administrator
Oct 18, 2016
9,303
4,331
0
AZ
Ride
2009 E93 335i
Looks like you nailed it, Tyler. Is 176F while cruising your goal?
Considering my Tstat doesn't open until 160, anything under 180 and closer to 160 is acceptable. I have not tested this in the 110-115F temps we get every year so I'll have to wait until next year to find out how it handles that.

I'm not done with it yet as I think there are a few things which can be improved.

  • Ducting/shroud, since it is just a hole in the bumper there is likely tons of turbulence. The addition of some duct work that also fits around the fan and makes a moderate seal should help cooldown times at all speeds.
  • Replace 180F thermal switch with 150F
  • Try and find a more efficient core that will fit the given space
  • Secondary cooler - I am moving my engine oil cooler in front of the radiator and will be using my 72 row setrab for this purpose. This free's up the driver side location and allows me to add a second cooler in this area. Here is something overly complicated I had thought up:
31464



(And just wondering out loud what is an ideal transmission fluid temp?)

According to a bobistheoilguy thread, they are saying 150-180. Here is a quote from another website:

The ideal fluid temperature is under 175 degrees, but as fluid ages it starts to break down and lose its capacity to cool down the transmission. This is when transmission overheating occurs. At 220 degrees, varnish forms. At 240 degrees, seals start to harden. At 260 degrees, you’ll often experience transmission slipping as plates slip. At 295 degrees, seals and clutches start to burn and fluid forms carbon, at which point transmission failure might happen soon. But with every 20 degree drop in fluid temperature, your transmission’s lifespan can approximately double!

Seems to me once the fluid hits 160-170 there really is no reason to allow it to go higher than this. Personally, I could probably just delete the thermostat but I like to retain full functionality and that includes the reduced warmup times a thermostat allows.

The last test is how the cooler performs while under load and in extended stop and go situations. I don't expect it to keep up simply due to the cooler efficiency and size. This is my primary motivation to add a second one. Some people stick them in front of the radiator since you can easily put one large cooler up there, however I just do not see the point in sending your transmission heat into your engine coolant and oil circuits.
 
Last edited:
  • Informative
Reactions: Jeffman

Jeffman

Major
Jan 7, 2017
1,618
1
628
0
Thanks for the info, Tyler. I regularly monitor my coolant and transmission temps using MHD. (I have stock 6HP21 / stock coolant setup.). In ~80F dry weather my coolant temps reach steady state 210F in about 10-15 minutes, but I’ve observed the transmission temps take about about twice as long to reach steady while highway cruising, about 20-30 minutes. Then transmission temps equal coolant temps, about 210F...

Based on your bobistheoilguy data, I think one key takeaway is if you have a stock AT Cooling setup like I do, then you should plan to regularly change your transmission fluid (and filter). Mike Miller of BMWCCA tech guru fame recommends ATF changes every 30K miles for the average BMW/driver. I suspect Spoolstreeters like us who “work” our transmissions more than average should probably change the ATF more frequently, like every 15K miles, especially if we have stock AT Cooling. With your setup reaching 180F max your ATF changes can probably be longer.