The Stovebolt Site Forums The Shop Area The HiPo Shop Electric Fans - Temp Control?

I have installed an electric puller fan on my V8 54 project and am looking for suggestions/recommendations on which temperature control unit should be used. The fan is a two speed unit and I want the low speed (2400cfm) to kick on at 180 degrees and the high speed (3200 cfm) to kick in when the "to be installed" AC compressors starts up.

Has anyone installed one of the temperature controlled fan sensors. What brand? How did you wire it up? Installed in manifold or head?

I just installed an "Old Air" a/c Hurricane system....am still using my pump mounted fan but did use a pusher in front of the condensor for extended periods of idling.

Old Air offered a kit that had the fan running off the water jacket (Thermostat housing) and the second trigger, off the trinary switch that comes as an option with most a/c system kits. This is a high/low switch that works off head pressure of the a/c. Check out their site as the whole setup is under $50.

Dave

You will want the temperature switch to be toward the radiator or on the radiator. If it is in the block before the thermostat, it will hunt and drive you batty.

My switch is a tube installed between the fins on the radiator

I have an electric fan and a switch like gazim's and I asume his has an adjustable stat like mine, but with my aluminum radiator it runs too cold. Too cold is easier to fix than too warm.

I have two puller fans on an aluminum radiator and installed one temperature sensor for both in the intake manifold. No problems; turns them on at 185° and off at the same temp. If you have an aluminum radiator it's not recommended to install the sensor in or on the radiator due to electrolysis damaging the radiator. '57 3100 w/big block.

A good question is what radiator are you using? I have a Cobra in my 40.. It is having a hard time keeping up even with a elec fan. Plus the pump mounted flex one. I'm starting to think Alum. may be the way to go... When in traffic I can get her to 220 with no trouble at all..

By the way welcome new guy...

This was the sequence:

1. 1965 BB Chevy radiator w/engine fan - ran really hot (210-220) at all RPMs when temps were over 90°, afraid to idle it for long as the gauge started climbing. Not a fun situation.

2. Aluminum radiator (18" x 24", 1" tubes) with three Zirgo 1500CFM fans on a custom aluminum shroud - ran hot (210-220) above 95° at idle.

3. Ron Davis aluminum radiator (18" x 26", 1" tubes)custom shroud with two 13" Spal fans.

I installed A/C and the Ron Davis setup this winter and temps haven't been above 95° yet but it idles with the A/C on for long periods without ever getting above 190°. I use a Stuart water pump and have that bypass blocked. A drilled 180° Stuart thermostat to handle pressure changes, 18lb radiator cap.

Running alum radiator w/2 pusher fans. temp runs whatever thermostat I have, using a 185 now cuz it ran too cold with the 160 Have no shrouds or fan on the water pump

Gazim - With this temp sensor that has the tube on it, I assume it is a bulb looking affair a couple of inches long at the end. Where do you locate the bulb end of it in the radiator? I have one of these but never had any instructions for placement and such. How much CFM does you fan pull? What kind of relays are you using to power the fan? Amps?

Boy some of these questions I can't answer. I'm kinda a shade tree mechanic. The tube sensor is about three inches long and about 1/8 diameter. It was sent with a plastic gizmo you push between the fins and hold it against the core on the engine side of the Radiator. The fact that this might not give you a accurate reading is not important, you adjust the switch to match the temp you want them to come on. I don't know the CFM of the fans, They are dual fans approximately 12inches that I picked up at the local salvage yard for 5 bucks. I am running no relay at this time. a Very short lead from the voltage regulator to the temp control switch. They just come on automaticly at 185 degrees. T he only annoying part of this is they cycle on and off for 20min after I shut down. The fans have a inline fuse I installed that is rated at 20amp and I am not blowing it. so the draw must be less than that. Sorry I can't give you more info.

When choosing electric fans an important consideration is CFM as related to amperage draw and the alternator capacity. As a general rule of thumb for every 90 CFM you're going to pull one amp and the highest draw is on start-up of the fan.

As an example I run two engine radiator cooling fans drawing 20amps each and a transmission radiator cooling fan drawing that draws 15amps. All are installed with ignition on relays with two temperature senders; one engine, one transmission. That's 55amps of draw without temp sensors, ignition, stereo, lights or other electrical requirements.

For that reason, after watching the lights seriously dim way down at idle when the fans went on with the stock 60amp alternator, I went to a 140amp alternator that puts out 90amps at idle.

Hey Gaz, my buddy had an Old Air elec fan setup that ran after shutdown. We ended up connecting the main power + to the IGN instead of battery. I have a two speed fan from a Crown Vic, it has two sets of wires, one for each speed.

After a serious under dash electrical fire in another vehicle, I prefer separate power sources for fans, stereos, etc. using relays with individual fuses to the accessory(s) and ignition key-on wires for each relay.

http://good-times.webshots.com/photo/2239546800083629245UPRxnN

The image is the set-up for my fans that mounts under the dash. A wire directly from the battery to an 80amp fuse, connected to a four post distribution block, 30amp fuse for each line between the block and relays, 30amp fuse from each relay between the relay and accessory.

I have a separate distribution block for all key-on relay wires, which requires only one wire from the ignition to operate all key-on accessory relays.

Brian, I already had planned on doing just that. Us retired guys don't have enough time to get more than the necessry things done.

I have researched the different fan controllers for my project, and I think the one made by Spal is the best one available right now.
http://www.spalusa.com/fans/automated/accessories/fanpwm.html

I also think that they make the best electric fans, and will use one or two of them too

Grigg

Jay, you get stuff figured out yet? Betcha this thread has helped a bunch out.

I had narrowed it down to the spal sensor and controller. It appears to have a low and high setting that will work well with my two speed fan.
Thank you for all the information.

why are you using an 80 amp fuse??? for one wire????
distribute all those relays w/ separate fuse links to each relay using a 6- 8ga. (check out the entire amps in your system) off a dist block that can handle the amps off the Batt/Alternator.
it sounds like you have most of your eggs in one basket and when it blows.

:rolleyes: you are up a creek without locomotion :rolleyes:

BTW:
you should have two 30 amp relays for each fan because of start up current draw (only).
http://www.stovebolt.com/bboard/cgi-bin//ultimatebb.cgi?ubb=get_topic;f=3;t=002596#000001

http://www.stovebolt.com/bboard/cgi-bin//ultimatebb.cgi?ubb=get_topic;f=3;t=001440#000002

http://www.stovebolt.com/bboard/cgi-bin//ultimatebb.cgi?ubb=get_topic;f=3;t=001675#000010

I have, according to Spal, two fans for the engine radiator that draw 19.5amps in normal operation, 25amps max draw at start-up. The one fan on the trans cooler draws 6.3amps in normal operation, 9amps at start-up. that's a total of 60amps maximum draw if all three did start up at the same time, in back of an 80amp fuse.

Spal, and friends who also do these things, assured me a 30amp relay fused on both sides was more than adequate for the specs on each fan.

I'm certainly not adverse to making changes for a good purpose, safety being as good as it gets, but why would you recommend two 30amp relays for each fan?

One link you provided stated fusible links should not be used under dash, where my fan wiring is located.

FWIW, I am going with a Lincoln Mark VIII fan because they advertise 4500cfm! Those and the Taurus fans (for the 3.8l motor) are the most popular. i went a placed called dc control for the electricals. They have a ramp up and down unit and the sensors that clip right onto the radiator fins. I think the site is www.dccontrol.com I also agree with those who say that too much cfm is better than not enough Good luck with whoever you choose for a vendor.
Dan

That Lincoln fan is an excellent choice. I've wanted to use one on a couple of projects but never had the required clearance.

NOTE: The Lincoln Mark VIII fan will draw continuous currents of [email protected] & [email protected], and has a starting current in excess of 100A! You will definitely need to upgrade your alternator to a 3G-130A!

The later Crown Vics & Merc Marquis also use the big Mak VIII fan, got mine for $25 at the U-Pull-It yard.

One thing forgotten about electric fans is they are for idle traffic cooling only. I don't know how many have had cooling problems on old stuff or rod projects when running up the road. Newer cars with electric fans are designed so that there is enough cooling capacity concerning airflow when traveling the road at highway speeds. An electric fan CAN NOT pull as much air as a 50 mph road wind. Only an engine mounted fan can do this. Notice the H.P. drop pulling a steep grade when a trucks clutch fan is fully engaged. Takes alot of power to pull more air than road speed. Would take something like a 1 horse belt driven electric motor to acomplish this, and more electricity than our vehicles make. They are a good solution for idle traffic cooling with ac or what not, but not a suitable replacement for an engine driven fan unless cooling has been oversized to accomadate this. Sorry, just had to put my pennys in. I have just had to many of these arguments with others who make mods, engine swaps or the like, and then figure, "ohh and electric fan easy solution". Not always the case.

I somewhat disagree, I think that a properly sized and engineered electric fan and shroud can be more than adequate on a vehicle.
My VW Jetta has only electric fans, and never overheats even with the AC on in traffic.

Look at this, http://www.flex-a-lite.com/auto/html/diesel-fans.html
Flexalite offers electric fans and shroud assemblies to replace the engine driven fans in diesel pickups.

I expect that most of the people who buy the fans will tow something, as that's why most people buy diesel trucks.

I don't think Flex-A-Lite would sell a product that will disappoint customers and cause vehicles to overheat.

So, perhaps the old thinking is that electric fans don't perform, but today they do.

I plan to use one or two Spal electric fans on my 48 Chevy 2 ton with a diesel engine. And from what I have seen and heard from other people using only electric fans I don't expect to have any issues with them. I have two friends with diesel pickups that run electric fans only, and they have no problems even with a load.

Grigg