Running aux fan only...what temperature switch to use?

[bmwpower]

I can't seem to find a 82C temperature switch as Jim suggested. Bavauto only has a 80C/88C.

What is everyone else doing? Running a lower degree thermostat (71C, 75C, etc)? Or just use the 80C/88C temperature switch over the stock 91C/99C switch?

As Jim mentioned, and it makes sense, you want the fan to come on high a few degrees above when the thermostat opens to cool the car, but to not let the fan run all the time when on the track.

[bmwpower]

Never fails.... Will this work?

https://www.bmpdesign.com/product-exec/product_id/3603/category_id/120/search_year/1983/search_model/15

[kishg]

Using 80/88 with a 75C thermostat.

[bmwpower]

Using 80/88 with a 75C thermostat.

Is the fan coming on when driving? Or only after pitting?

[kishg]

Is the fan coming on when driving? Or only after pitting?

only when idle in pit lane. don't really need it when driving on the track.

[jlevie]

The BMW switch will work.

[bmwpower]

The BMW switch will work.

Huh? You said to go with 82C. Which one do you mean?

[bmwpower]

bump......

[Herb]

I used all stock s52 gear, and had a "constant on" electric fan (not needed, just got wired that way), zero problems on the track.

[kishg]

Huh? You said to go with 82C. Which one do you mean?

i think he meant the BMP one will work.

[bmwpower]

i think he meant the BMP one will work.

Ok, that makes more sense. When he said BMW, I was like...wha?

[Skafrog]

Use the stock aux fan connector so you can manually turn it on with the AC button. In addition, you will still be able to rely on the stock temp switch to auto turn the fan on.

[bmwpower]

Use the stock aux fan connector so you can manually turn it on with the AC button. In addition, you will still be able to rely on the stock temp switch to auto turn the fan on.

The only worry I have about doing that is the side effects of having the A/C switch on....idle bump and whatever else goes along electronically with having the A/C on.

Unless I just somehow rewire the switch to only turn the fan on and remove the link to the ECU for the idle bump...I need to look at the diagram again...

[Mohammed_A]

The only worry I have about doing that is the side effects of having the A/C switch on....idle bump and whatever else goes along electronically with having the A/C on.

Unless I just somehow rewire the switch to only turn the fan on and remove the link to the ECU for the idle bump...I need to look at the diagram again...

this is a track car right??? how come u still gonna have air con pump installed.... as far as i know the idle bump and power loss comes due to the air con pump being activated, in my opinion if it is your track car then remove the pump

[bmwpower]

this is a track car right??? how come u still gonna have air con pump installed.... as far as i know the idle bump and power loss comes due to the air con pump being activated, in my opinion if it is your track car then remove the pump

I'm not 100% sure, but I thought the idle bump was from the ECU and not a result of the compressor turning on.

A/C system is out of the car...