L20b electric fan setting?

[jon521]

So I have done some searches and havent really found much. ive been wanting to put an electric fan on my L20b for awhile now, and a few months back i picked up an aftermarket fan from a junkyard, this is very similar to the one have here: http://www.daviescra...72-details.aspx

 

so my question is, what are you guys using for electric fan sensors and/or what temp do you have it set so the fan will come on?

 

Thanks!

 

BTW im using a stock 521 rad

[datzenmike]

I would place the sensor in the return line where it is coolest and have it set for about 180 or whatever the thermostat is. I have no idea why people insist on placing them on the outlet from the motor. This is the hottest place and does not allow the rad to do it's job first. Only when the water entering the motor is too hot does the fan need to come on.

[Boaty]

Find a 200-170 or so. Doesn't really matter much, to be honest. You want it to be slighly over thermostat temp so it'll actually get to temperature, and you want it to turn off after it cools below thermostat temp.

 

On my KA I'm running a 180 on 155 off. Really cold, but it's on the cold half of the radiator, and it cools very quickly.

 

Make sure when you install it that you use switched power with key ON (not ACC). Or else you'll end up with the fans on even if the car is off. No bueno.

Pico #5591PT will help you greatly for your install. Nice pigtail and relay. :)

[Uber Deaf One]

Find a 200-170 or so. Doesn't really matter much, to be honest. You want it to be slighly over thermostat temp so it'll actually get to temperature, and you want it to turn off after it cools below thermostat temp.

 

On my KA I'm running a 180 on 155 off. Really cold, but it's on the cold half of the radiator, and it cools very quickly.

 

Make sure when you install it that you use switched power with key ON (not ACC). Or else you'll end up with the fans on even if the car is off. No bueno.

Pico #5591PT will help you greatly for your install. Nice pigtail and relay. :)

 

Don't you want the fans to stay on after you turn the car off? If the coolant is hot enough of course...

[datzenmike]

My Sundance is wired this way. The fan has a warning that it could come on at any time even with the key off. All motors over heat slightly just after they are shut off. You could run it either way, after all non electric fans stay off with the motor and they are fine.

[Laecaon]

My VW has the fan stay on after car is off... My datto has a fan on the waterpump, so off with the motor.

 

And Boaty, doesnt ACC turn off also with the key, otherwise my radio would never turn off.

[kelowg]

Ive had mine wired on acc 6-8 yrs with one problem. Think about it, engine alittle too hot fan relay sticks on killing battery

 

[datzenmike]

The fan won't stay on for long a few min at most.

[Boaty]

My old fan set up used the original Air Conditioning lead as the switch for 12V in, with a probe-thermoswitch (which SUCKS). The Air Conditioning circuit see's power with ACC and ON positions, and is dead in START. It will work in a pinch, but keeps the fans on in the ACC position. So if the rad is still hot, and you want to just chill and listen to the stereo - your fans will be on. Not ideal.

 

I now pull switch power through the black/white (key in ON position only) which goes to the thermoswitch mounted in the radiator, then back to the relay. Grabs fan power directly from the accessory fuse box located in the car, each with a 20A fuse. To be technical, since I'm using that for the switched +12V for the ECU/ECCS/Fuel Pump Relay, so it functions as it would if it were factory. This circuit is also fused and protected, so if THAT ever blows a fuse, I'll definitely know it - the engine won't run. It's a basically zero-load on the system now as it only powers relays, no coil or anything - should be fine.

 

This isolates everything and keeps the stock wiring unloaded as it's only being used to switch the relay on when the thermoswitch closes.

 

No electric fan should stay on with the key off. If you're anal about it, run an override with a toggle switch. If a thermoswitch (temp switch mounted in radiator) ever goes bad, it's a sure fire way to kill a battery. There is no need to continue running the fan if the engine is off and the key is not in the ON position. The water isn't circulating anyways. It's easy to mount a toggle this way, however - simply run a toggle to bridge the leads going to the thermoswitch. Doesn't even require a fuse since it's all fused at the header lead anyways.

 

EDIT: Additionally you could add a kill switch for the fan system. One must be on for the temp switch to even activate (just mount it upside down so it doesn't look funky under normal conditions), and one to break the switched connection. Even a 3-position toggle would work for this. Not really necessary to do this, but being technical - it's easy to do.

[jon521]

I see. so it dont need to run with the engine off, but its not going to hurt it. i want a sensor that comes on slightly over what my thermostat opens up at, but shuts off below what my thermo. closes at, correct?

 

but i was also wondering what sensor you guys use particularly. i know there are those aftermarket ones that stick into your rad, but ive heard those are just cheap and dont do there jobs too well....

[Boaty]

You're referring to the probe inserts. It's a capillary tube and come coiled up. Most people just squish them into their radiator core, but technically they are supposed to be inserted into a radiator hose. Yes, they are cheap but they DO get the job done. Not accurate even in the slightest, and the three I've used/gone through/worked on, never kept the correct temperature. You have about 3' or so of wound up capillary tube that can't be shortened, so you then have a nice big fatty coil of ugliness hanging out somewhere around your radiator. This also prohibits where you can mount it, and in my opinion is all bad and should only be used as a last resort.

 

THAT being said, if you're using a stock 521 radiator - you won't have provisioning for a temp sensor like late model cars. I am personally using one from an 80's VW, because it was the same threads as the drain plug in my CXRacing radiator. With the older cores, you're forced to use the probe type thermoswitch, or you can use an in-line hose fitting with a temp sensor. I BELIEVE a stock 240sx has one in the lower radiator hose, so if you're at a junkyard... there ya go. I do believe it's smaller diameter than an early Datsun hose, though - you'd have to have somebody with one in their hands to check for you. I couldn't find mine (but when I do I'll be running a two-stage fan set up).

 

The VW sensor I'm using is a 180 on, 155 off. As I said it's a little on the cold side but it cools very quickly (brand new aluminum radiator) so I'm not really concerned with it.

I think an ideal temperature range would be 200 on, maybe 170 off? I think the stock 240sx (KA24DE) is a 205F on, 170 off, not sure on that. It really isn't THAT big of a concern to be honest.

 

If you use the probe style thermoswitch and just push it in the core fins, just get your car up to temperature and then adjust the fan to come on just after by using a thermometer. Say, if you had a 192F thermostat, set it to turn on at 200F. Or, if you have a 180F thermostat, set it to turn on at 190. The off temps will always be significantly lower than your thermostat anyways unless you use a 160F thermostat (which is kind of meh since it's been proven an L-series makes best power @ 190F +/- 5)

 

At any rate, don't be TOO concerned with what temps you get, and if it's an adjustable just remember to set it to turn on just over thermostat temp and you're golden.

 

Remember: Switched power with ON not ACC ;)

[jon521]

Thanks man! i will keep an eye out next time im at the junkyard