Lets talk fans

[wetoolowdingbangow]

One simple bit of logic will probably help a lot too:


Any electric fan setup that doesn't pull a TON of amps when it's running, also isn't moving much cool air.



No free lunch. If you want to save the HP by ditching a mechanical fan, your are going to probably need a bigger alternator to run a serious electric fan setup.

When I was figuring out my radiator setup, I called Ron Davis Racing. They sold me an enormous radiator that I think they call the "Offroad Truck" application. Two big electric fans with a custom shroud.... I forget what the current draw is, but it's something ludicrous like 50A+ when both of them are running at full speed / full load.

They told me that they tested a lot of fans and most couldn't move the advertised CFMs once they were actually installed behind a radiator. They could only get the advertised CFMs spinning in open, unrestricted air.... which basically makes those specs useless for comparison.

A good fan has a strongly angled blade and a strong electric motor to work against that load when it's spinning.... I had a set of Summit Racing "Flex-A-Lite" fans on my old BBC setup and I think they ran on a 10A fuse (or less!)... knowing what I know now, it doesn't even make sense that they would do the job correctly.



-G

I totally here you on the amps being pulled. As with any rating its with the "wind at your back" with this stuff. I figure if most people are saying windstar then thats likely the direction im headed. Im also only cooling a small block. My dads L88 corvette puts out about 700 NA hp and he has one hell of a radiator and fan setup. I definitely dont need anything that crazy as mud is pretty rare out here and im not racing.

I ran camaro fans for awhile but they were too small for the surface area of the radiator. They did ok, but I still had occasional heating issues. I switched to windstar fans and never looked back. I love them. For the price and performance I don't see any reason why you'd go with anything else.

I used to run them off a temp probe that was just stuck between the fins of the radiator. I never had any issues with it but I was always worried about how accurate it was. After my LS swap I let the PCM control the fans. I do want to wire in a cut off switch at some point for water crossings though.

Another valuable vote for windstars. Thanks for posting up.

Since it appears these windstar fans are the shizznit, you guys should look up your local LKQ Salvage yard. I have a bunch in my system for like $25. And all our parts have a 6mo warranty. I am going to pick up a set just to have them.

Edit: If you don't have a local LKQ, I can sell them to you. There would just be a little more $$ for shipping.

Yeah! I could get one from pick n pull but you may not come out alive from that place. Too much crossfire and tweakers bumping vehicles over. $80 for a new one from rockauto...makes me feel a little better that its new too...

 

[Greg72]

I totally here you on the amps being pulled. As with any rating its with the "wind at your back" with this stuff. I figure if most people are saying windstar then thats likely the direction im headed. Im also only cooling a small block. My dads L88 corvette puts out about 700 NA hp and he has one hell of a radiator and fan setup. I definitely dont need anything that crazy as mud is pretty rare out here and im not racing.

Fair enough.

The Windstar fan is cheap enough that's it's probably worth trying first and assess how well it works in your application.

While you might not be doing full-throttle assaults in the mud, you can still build a LOT of heat doing low-speed crawling on steep terrain....especially if you don't have very deep gearing in the axles/transfer case. Bad gearing makes the engine work a lot harder to build the torque you need to get up and over obstacles. I learned that one the hard way on my first trip to Moab in 2003... My feeble electric fan setup was no match for a day of moderately difficult wheeling.

-G

 

[Cili]

Just out of curiosity, go out to your truck and give the fan a spin by hand and see how much resistance it has.

I'm going to bet it spins around pretty easily, indicating that the clutch is not working properly. No guessing at parts there.

Also just some general information. The clutch changes how much "slip" it has depending on what the engine needs. It adjusts if the engine is getting warm and will lock up.

Now going down the road the clutch is usually completely disengaged as just the air and road speed is enough to cool the radiator. That's why yours works fine for that, because the fan isn't needed.

Personally, I would fix the problem at hand. Even though most people have good luck with the windstar fans, I've had way too many bad experiences using after market parts and modifying stuff that isn't necessary.

 

[Russell]

The mechanical fan on my LB7 is rated for 10,000 CFM under full power. It also slows the truck down noticeably when it locks in. The only time it does so is when the fan clutch is frozen up in the winter, it releases after the engine starts making some heat and it thaws out. There isn't an electric fan out there for automotive use that comes anywhere near that air moving capacity.

I'm fairly certain that most mechanical fans on the older trucks are rated for between 6 and 7000 cfm. That explains why a 5000 cfm rated electric fan can't quite keep up when you are working the engine to it's limit.

I still say that if your mechanical fan isn't cooling your rig, you've got another problem somewhere.

If your rad is good, your thermostat is good, and you are full of coolant (and not air locked) then I'd start looking at the fan clutch. It may not be engaging.

 

[blazinzuk]

Russel is absolutely right. Years ago hot rod did a test. Most aftermarket fans pulled 75% of their rated power. The mechanical fans very rarely have published ratings but even the cheapest non clutch mechanical fan pulled double what the best electric pulled.

But for a gas motor the windstorm seem to work very well.

I had a huge like 8 blade fan on a dart I had years ago. Don't even have a clue what it was off of. It pulled so much if the car was on and you dropped a rag within 3 feet of the front of that car it would never hit the ground. Just sucked onto the grille

But windstorm are proven and OEM fans are usually way better than aftermarket

 

[Blue85]

I don't see the point of installing electric fans unless they are switched automatically based on temperature. A lot of the "fuel savings" is because they don't have to run all the time. In cooler weather they might not run at all on the highway.

I think the best choice depends on the vehicle and what you're doing with it. If you're pulling a trailer through the mountains, a mechanical fan is likely to pull more air while you keep the RPMs up. For cold A/C at idle, the electric wins. I've driven with no fan at all (not by choice) in 100 degree weather and the engine ran about 220 while cruising. Coming to a stop would push it towards the red in seconds.

 

[JoshHefnerX]

If any of you guys are familiar w/ Corvairs (air cooled) they run a mechanical fan and I can't remember the numbers behind it but it's a lot. Guys have been trying for years to put electric's on there because the fanbelt setup on these suck. Not 1 has been able to keep up w/ cooling. Part of it is because w/ the fan you're pressurizing the air somewhere (either infront or behind depending on the design), and the electrics can't pressurize the air - not enough power.

If you want a really cheap test find a spacer block and use that to replace your fan clutch. You'll know then if your clutch is bad.

 

[Russell]

I don't see the point of installing electric fans unless they are switched automatically based on temperature. A lot of the "fuel savings" is because they don't have to run all the time. In cooler weather they might not run at all on the highway.

I think the best choice depends on the vehicle and what you're doing with it. If you're pulling a trailer through the mountains, a mechanical fan is likely to pull more air while you keep the RPMs up. For cold A/C at idle, the electric wins. I've driven with no fan at all (not by choice) in 100 degree weather and the engine ran about 220 while cruising. Coming to a stop would push it towards the red in seconds.

Mechanical fans freewheel unless the air coming through the rad is hot enough to lock the clutch in, or if it is frozen. The fan still spins due to parasitic drag through the clutch but it isn't spinning full engine rpm.

The mileage gains going electric would be marginal at best. A/c still works great at idle with a mechanical fan as it does still move air even when it isn't locked in.

 

[Fordum]

I think one of the best fans I have come across is still being made, but lots of people don't like them, and they are probably not the best fit for this use.

This is the outfit that invented them, I think.

https://www.flex-a-lite.com/belt-driven-fans.html

But I want to say that there is another company that makes a more aggressive version.
The one I worked with would move a ton of air at idle. Way more than the factory fan. It was great for long idling sessions or driving really slow looking for tracks in a road on a hot day.
But, when you rev it up, the blades flatten out and it has less drag than stock.

The only downside, is that if you rev the engine standing still to try to cool it off, you are losing airflow.
But, the darn things move so much air at idle, you seldom have to.

I have heard several people say they can fail and come apart or don't do good in water, but the one I helped put in a friend's truck never failed and he went under water with it a couple of times.

 

[dyeager535]

Part of the difference also is likely to come from the way the shrouds are designed. All the factory fans I see are far enough back from the radiator, that the shroud covers the ENTIRE radiator surface. While electric fans sometimes don't sit fractions of an inch from the radiator, they are not effectively pulling across the entire surface of the radiator. IMO the way they are designed, the only parts of the radiator getting effective cooling, is what is directly under the fan blades.

Russ, not questioning your statement, but where did you find the fan CFM specs for the LB7? Having real numbers from a reliable source is definitely useful. 10,000CFM is ridiculous, but not surprising.

While economy MIGHT be helped at slower vehicle speeds by running electrics on a thermostatic switch, even if they are on when you are going 60MPH, they are going to be "overdriven" by airflow and will not be a draw. Personally I wouldn't run electrics without an automatic on/off. It's not hard to wire them up to run automatically, and if something comes up while the vehicle is running and you get out, warming it up, etc., you don't have to worry.

 

[Russell]

Part of the difference also is likely to come from the way the shrouds are designed. All the factory fans I see are far enough back from the radiator, that the shroud covers the ENTIRE radiator surface. While electric fans sometimes don't sit fractions of an inch from the radiator, they are not effectively pulling across the entire surface of the radiator. IMO the way they are designed, the only parts of the radiator getting effective cooling, is what is directly under the fan blades.

Russ, not questioning your statement, but where did you find the fan CFM specs for the LB7? Having real numbers from a reliable source is definitely useful. 10,000CFM is ridiculous, but not surprising.

While economy MIGHT be helped at slower vehicle speeds by running electrics on a thermostatic switch, even if they are on when you are going 60MPH, they are going to be "overdriven" by airflow and will not be a draw. Personally I wouldn't run electrics without an automatic on/off. It's not hard to wire them up to run automatically, and if something comes up while the vehicle is running and you get out, warming it up, etc., you don't have to worry.

No official source on that spec, just read it on the diesel place forums or something similar.

 

[bp71k5]

When I was running a temp switch and relay, I accidentally flipped the fan "disable" switch I had for water crossing in case it ever rains here again. . I towed a small tent trailer back through the mountains and home about an hour and never saw the water temp get much above normal. Once I got home and was trying to back the trailer into the driveway, I smelled coolant and looked down to see the temp gauge spiked right before the radiator hose blew and shot steam and coolant everywhere. So my experience is that the fans may not be needed as long as there is air moving across a properly sized functioning radiator and thermostat. If guess those situations are idling, rock crawling, towing, etc)

I've now been running a PWM controller on mine and it cycles on and off at idle but the fans rarely get up to high speed even when it's just idling. I used to be able to see the voltage gauge drop when the fans kicked on and now they cycle on and off without budging it. This tells me a stock motor probably doesnt need insane CFM to keep things cool.

 

[wetoolowdingbangow]

Fair enough.

The Windstar fan is cheap enough that's it's probably worth trying first and assess how well it works in your application.

While you might not be doing full-throttle assaults in the mud, you can still build a LOT of heat doing low-speed crawling on steep terrain....especially if you don't have very deep gearing in the axles/transfer case. Bad gearing makes the engine work a lot harder to build the torque you need to get up and over obstacles. I learned that one the hard way on my first trip to Moab in 2003... My feeble electric fan setup was no match for a day of moderately difficult wheeling.

-G

Good point. My gearing is not the best and im working the truck pretty good. Im sure when i re-gear things will get better.

Just out of curiosity, go out to your truck and give the fan a spin by hand and see how much resistance it has.

I'm going to bet it spins around pretty easily, indicating that the clutch is not working properly. No guessing at parts there.

Also just some general information. The clutch changes how much "slip" it has depending on what the engine needs. It adjusts if the engine is getting warm and will lock up.

Now going down the road the clutch is usually completely disengaged as just the air and road speed is enough to cool the radiator. That's why yours works fine for that, because the fan isn't needed.

Personally, I would fix the problem at hand. Even though most people have good luck with the windstar fans, I've had way too many bad experiences using after market parts and modifying stuff that isn't necessary.

Ok thanks. Im going to give it a try here shortly.

Russel is absolutely right. Years ago hot rod did a test. Most aftermarket fans pulled 75% of their rated power. The mechanical fans very rarely have published ratings but even the cheapest non clutch mechanical fan pulled double what the best electric pulled.

But for a gas motor the windstorm seem to work very well.

I had a huge like 8 blade fan on a dart I had years ago. Don't even have a clue what it was off of. It pulled so much if the car was on and you dropped a rag within 3 feet of the front of that car it would never hit the ground. Just sucked onto the grille

But windstorm are proven and OEM fans are usually way better than aftermarket

Sounds about right to me. I guess my fan is probably not up to par clutch wise.

I don't see the point of installing electric fans unless they are switched automatically based on temperature. A lot of the "fuel savings" is because they don't have to run all the time. In cooler weather they might not run at all on the highway.

I think the best choice depends on the vehicle and what you're doing with it. If you're pulling a trailer through the mountains, a mechanical fan is likely to pull more air while you keep the RPMs up. For cold A/C at idle, the electric wins. I've driven with no fan at all (not by choice) in 100 degree weather and the engine ran about 220 while cruising. Coming to a stop would push it towards the red in seconds.

For me the replacent of my mechanical fan comes from a few different angles. I want to free up more space in the engine bay, keep the engine cooler, getting rid of the shroud, one less thing on the pulley system. I totally agree that it should be hooked up to sensors. I might be thinking about boobies and forget to turn the fan on.

Some other folks ive talked to who are running tbird fans on a 2 speed switch are keeping their trucks cool, while rock crawling on the low setting. Thats sort of what im looking for.

Sure i could fiddle around with my mechanical fan but i just like everything the electric one offers.

 

[ashman]

I should point out that the original reason I went with electric fans was my body lift making the stock shroud unusable. Obviously the lack of a shroud was the "real" problem, not my mechanical fan.

That said, the windstar fans do great and I got the added benefit of them taking up less room and being able to lean into a running engine without risking life and limb.

 

[dyeager535]

I ran my truck around without a fan for a bit, 25MPH or so seemed to be the magical number where flow-through cooling was not a problem. This was just street driving though, off road lugging the engine up hill the temp will climb fast until the cooling fan comes on.

One thing I'll give the electric fans...they sure seem to last for a long time. I haven't grabbed a bunch of them, but the ones I've monkeyed with all still work, even from the mid 90's.

 

[wetoolowdingbangow]

I should point out that the original reason I went with electric fans was my body lift making the stock shroud unusable. Obviously the lack of a shroud was the "real" problem, not my mechanical fan.

That said, the windstar fans do great and I got the added benefit of them taking up less room and being able to lean into a running engine without risking life and limb.

This is exactly why im doing this. Im going to do a 1 inch body lift soon so itll become a headache...unless i do the E-fan.

I ran my truck around without a fan for a bit, 25MPH or so seemed to be the magical number where flow-through cooling was not a problem. This was just street driving though, off road lugging the engine up hill the temp will climb fast until the cooling fan comes on.

One thing I'll give the electric fans...they sure seem to last for a long time. I haven't grabbed a bunch of them, but the ones I've monkeyed with all still work, even from the mid 90's.

Yeah i havent heard too many failures with the E-fans. I plan on getting a oem replacement fan.

 

[Blue85]

Most factory fans are very reliable, but a retrofit is only as reliable as the wiring, switches and relays. It just takes one high resistance crimp (like using a dreaded butt connector or a Chinese relay socket) to leave you fanless and overheating. Of course it's most likely to fail during the hottest conditions.

 

[dyeager535]

No argument there. I would source the proper gauge wiring and connectors for whatever I was going to use for relays (and they would be locking, no question) and make the wiring complete. No soldering, no splicing, all new wiring except where you might need it, such as the fan motor pigtail.

 

[p0ps45]

I've now been running a PWM controller on mine and it cycles on and off at idle but the fans rarely get up to high speed even when it's just idling. I used to be able to see the voltage gauge drop when the fans kicked on and now they cycle on and off without budging it. This tells me a stock motor probably doesnt need insane CFM to keep things cool.

I'm also running this set up. Take a look at the Spal PWM (http://www.spal-usa.com/fans/automated/accessories/fanpwm.html it has default start/stop temps as well as programmable by you. Also is variable speed to ramp up the fan speed as temps climb. I run these in Sacramento where the summer temps exceed 95+ on a regular basis and the truck stays cool, rarely does the second fan cycle on.