Electric cooling fan, LMC, not as effective - need advice on shrowd physics.

[Rangergirl92]

I bought an electric cooling fan from LMC truck to take load off the motor and improve hp, mpg, torque. I got all those benefits and they were better than id hoped! But the motor gets up there in temps now. She's a 92 so the gauge has L to H with a "normal" range. Sits fine on highway. A/C compressor engagement bumps it up but only a little on its own. In stop and go or "around town" diving it goes to the high side of normal. Hasn't technically overheated and i can make it work. I had the shroud out at first. Installed it and it seems to help a smidge.

Should i retrofit the system so the fan sits away from the radiator and mounts to the shroud instead of directly to the radiator or should i get the flex o lite model with the aluminum shrowd? Is 16" fan just too small. Looking for any suggestions or experiences and product recommendations.

Thx y'all.

 

[RonD]

Shroud's purpose is so the fan can only pull in air THRU the radiator fins
Its way easier pull in air from the sides(inside engine bay) than thru radiator fins

Yes, if you don't have a shroud it will help
You can often use original shroud to cut and build a new one for an e-fan
Or find an E-fan shroud in wrecking yard

Mechanical or electric fans are only used/needed at lower speeds or when stopped, above 30MPH the vehicles speed is forcing more air thru radiator than any fan could, so an e-fan should shut off, the benefit of e-fans

Generally speaking a 4cyl needs about 1,500CFM fan, V6 2,000CFM fan
But a 2,000-3,000CFM two speed fan might be better in a V6
Whats the CFM on the 16" fan you have now?

 

[PetroleumJunkie412]

I used aluminum bar stock to put the e fan at the round bit of the factory shroud.

Helps.

 

[bobbywalter]

which fan do you have exactly?

 

[Rangergirl92]

which fan do you have exactly?

It was a kit I got from LMC truck's website. The fan is 13",8 blades with an output of 1560CFM

Electric Cooling Fan Kit Keeps Your Engine Cool

Shop from thousands of parts and accessories to help you restore, maintain, and customize your Chevrolet, GMC, Dodge or Ford truck or SUV. Keep 'em on the road with the right part, right price, right now.

www.lmctruck.com

 

[Rangergirl92]

I bought an electric cooling fan from LMC truck to take load off the motor and improve hp, mpg, torque. I got all those benefits and they were better than id hoped! But the motor gets up there in temps now. She's a 92 so the gauge has L to H with a "normal" range. Sits fine on highway. A/C compressor engagement bumps it up but only a little on its own. In stop and go or "around town" diving it goes to the high side of normal. Hasn't technically overheated and i can make it work. I had the shroud out at first. Installed it and it seems to help a smidge.

Should i retrofit the system so the fan sits away from the radiator and mounts to the shroud instead of directly to the radiator or should i get the flex o lite model with the aluminum shrowd? Is 16" fan just too small. Looking for any suggestions or experiences and product recommendations.

Thx y'all.

CORRECTION: it is a 13" 8 blade fan kit from LMC truck. I bought the thermostat as well. It has an output of 1560CFM.

 

[Rangergirl92]

Shroud's purpose is so the fan can only pull in air THRU the radiator fins
Its way easier pull in air from the sides(inside engine bay) than thru radiator fins

Yes, if you don't have a shroud it will help
You can often use original shroud to cut and build a new one for an e-fan
Or find an E-fan shroud in wrecking yard

Mechanical or electric fans are only used/needed at lower speeds or when stopped, above 30MPH the vehicles speed is forcing more air thru radiator than any fan could, so an e-fan should shut off, the benefit of e-fans

Generally speaking a 4cyl needs about 1,500CFM fan, V6 2,000CFM fan
But a 2,000-3,000CFM two speed fan might be better in a V6
Whats the CFM on the 16" fan you have now?

Hey thank you for the information and clarifications. I made a mistake it is actually a 13" 8 blade fan kit: https://www.lmctruck.com/1983-11-ford/cooling-system/fr-electric-cooling-fan

So could I get little "L" brackets to adapt the factory shroud then? Where can I find such brackets? Hardware store? Amazon? Any suggestions for modifications would be greatl;y appreciated!

 

[RonD]

1,500cfm is not quite enough for a V6 engine, probably OK in most temps but summer would be the challenge

If you have a single core radiator(manual trans) you may want to go to a double core(automatic), Ranger used both so it fits no problem, the extra coolant allows more heat dissipation

Adapting a shroud to e-fan is just trial and error unless you can find a post/article that used the same e-fan you have and same Ranger shroud

 

[Kira]

Any suggestions for modifications would be greatly appreciated!

That'd all be sheet metal work, no? Fabricate or alter junk yard finds.

 

[gaz]

@Rangergirl92 ,
Recommend NO LESS THAN a 2,800cfm or greater, CORRECTION...15" electric fan.

While driving greater than 35, I do not need the fan on unless towing or going through a mountain pass; even then moving 44-55 mph I did it for piece of mind. When stopped, in stop-n-go traffic or at speeds under 35, my fan is on.

If I were using an air conditioner, I would add a second fan, a pusher to the front of the radiator, dedicated to the a/c; whenever the a/c is on, that fan would be on.

Using an electric fan without a shroud is REALLY asking for trouble; the fan may only get 10% of the drawn air through the radiator, the bulk of the air will be scavenged from the sides.

A 16" fan is very easy to use with a stock shroud. I have also fabricated a custom shroud from sheet Aluminum (Al). The Al looks nicer but weighs more and was not free; I gave it a try, hoping that the Al might offer some augmented heat dissapation, essentially a big heat sink.

 

[rubydist]

I agree, the fan you currently have is not moving enough air.

 

[bobbywalter]

i would not use that fan in anything.



i would force this one in there though....

or a volvo fan.

Amazon.com

 

[Rangergirl92]

Okay everyone, first I wanted to thank you all for your recommendations and insight - it has been very helpful in reassessing nad finding the right parts for this upgrade!

I have decided to do the following:

I am picking up a 16" 8-blade fan with a 3000 CFM max output for $50.

I can easily mod my current wiring harness to create a dual speed rate when the A/C is on as well. I would use a two relay system to deliver a "standard" and a "high-flow" voltage rate to the fan based on (a) the thermostat start signal, and (b) the AC clutch engagement signal I would tap from the compressor on the ac system and lead that into a relay. I worked in the auto diag world for way too long lol but if you guys have experience in wiring/electrical I am always looking for suggestions to improve my circuit designs to be safer and more effective. Thanks in advanced!

I am also going to install a Spectra Premium "heavy-duty" cooling w/ AC radiator for ~$100 (i.e. the one for automatic transmissions suggested by @RonD with 2 rows) and I am getting it from Rock Auto.

Here are the links to the products "in my cart" right now:

Fan kit: https://www.amazon.com/gp/product/B01N3YMULB/?tag=959media-20
Radiator: https://www.rockauto.com/en/moreinfo.php?pk=271476&cc=1137855&pt=2172&jsn=926

Any feedback would be much appreciated on these before I pull the trigger. If you have an all aluminum radiator brand or model that any of you would suggest that has more rows, all aluminum and/or just better quality but is less than $200 by itself I am all ears. Thx guys!

 

[don4331]

A couple comments (some symantics):

The pint of extra coolant in a two row radiator contributes very little to greater heat dissipation; twice the area for coolant to be in contact with air makes big difference.​

Does your existing radiator just need a flush? Radiator coolant needs to be flushed every so often or it doesn't do the job it once could.​

Adding an extra row to radiator might not make significant difference with your current fan.​

Fan is rated 1560 cfm with no resistance, with single row radiator, it will be xxxx (something less than 1,560), with single row radiator plus a/c condensor, it will be reduced further, and with two row radiator plus a/c condensor, reduced even more. The fan will have a curve of airflow vs restriction. Often a little more resistance drops airflow off a cliff.​

Aside: Friend had a built 454 in a Chevelle which had overheating issues with 3 row radiator, so he got a custom 4 row radiator - and had even more issues. The radiator had so much resistance to air flow, that all the cooling air went around the radiator, not through it.​

Too much air flown (probably not the case here) is just as bad as too little. Air must move slow enough to pick up energy (heat) from coolant. If it is going too fast, it just does a drive by.​

Brass is a better conductor of heat than aluminium, but aluminium is lighter. Finding a brass radiator these days is kind of unicorn, but they do work well.​

Air moves through path of least resistance. Fan needs to be set up, so only possible path for cooling air is through the radiator (may be with some cavaets to allow alternate pathes at speed). Adding ducting as suggested above helps a lot.​

​

Lastly, I would caution about making more than 1 change at a time. If you make a whole stack of changes you don't know which one(s) worked, and which were just waste of time and/or $$$.

 

[Lefty]

I got a bigger fan...works great...don't even need a shroud.