Build thread for custom fan controller. NERD alert.

[Rcastle]

Don't get me wrong, I commend you for coming up with something like this and am looking forward to seeing it work.

1st lesson learned. Don't buy the flex-a-lite fans for the 4Runner/Tacoma. They will shatter, they will go through your radiator, you will have a bad day.

Currently I am using 2 Flex-a-lite variable speed digital controllers

Flex-a-Lite Automotive Variable Speed Controller with Stainless Steel Temperature Probe

to control 2 separate fans, one is set to come on with the A/C and after I reach 200 degrees, the primary is set to come on at 190 I believe. I am supercharged with the 2.2 pulley and 7th injector with a 180 thermostat. Typically I sit between 188 and 195 which is pretty perfect operating temperature. I also have a switch to kick both fans on full bore or to shut them off for water crossings, etc.

here are the fans I am using.

Dual Powerpacks : High Output Dual 12" Electric RAD Fan/Aluminum Shroud Kit - 26"W x 18"H x 4"D

I have had problems with the probe sticking into the radiator gettting dirty or vibrating out so I have them in the radiator through the upper radiator hose with a little silicone around the wires to make sure they seal. This way they are always submerged in coolant at the intake to the radiator and I have never had a problem with this setup.

Currently this setup is working great but it took me a long time to get there.
I had the first flex-a-lite set shatter like I said, then I had both fans running through 1 controller and it burned it up because it was too much amperage draw.

To power the fans I have a separate 4 gauge wire run to a fuse block that uses ANL fuses as I found these worked best. Each controller has a 40 amp fuse.

After having to mess with these fans so much to get them to be reliable I personally think that the most reliable fan is going to be mechanical. Most often a fan clutch will fail on, electric fans will always fail off. That will leave you stranded. yeah a stuck fan clutch will suck balls till you get it fixed but it will get you home.

just my 2 cents

 

[phattyduck]

I have had problems with the probe sticking into the radiator gettting dirty or vibrating out so I have them in the radiator through the upper radiator hose with a little silicone around the wires to make sure they seal. This way they are always submerged in coolant at the intake to the radiator and I have never had a problem with this setup.

Those through-the-radiator sensors always seemed like a bad idea. I figure a sensor screwed into a bung somewhere (whether in hose adapter or somewhere on the engine) would be the best plan.

The mechanical and electronics side of this (motor driver) actually seems like much more of a challenge than the software control side of things.

-Charlie

 

[DaMonkey]

I received the OBD2 adapter, and it works. Did a simple sketch to show coolant, RPM, throttle, and voltage to see in action. I had to adjust a couple of the OBD calls.

SHORT VID of test

I'll assemble and just monitor it on truck first and get some real data on stock temps and also the condenser split temps so I know what ranges are normal.

I'm using the temp sender from ECU for fan control, but I'm not sure how that reading is treated with a failed sender. I'm suspecting that if ECU reads resistance out of range, it will CEL and simply run as if cold so that it will start and get home. This would be bad if my fans thought it was cold and things start to heat up and they don't turn on. I'm going to go ahead and use the ECU temp for fan control, but I'll put another sensor in as an override if things gets hot and alert driver of temp override. At least then I'll have redundant sensor protection, and I'll also have manual switch to turn on if my gadget STB.