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Fitting Larger Dual Electric fans

Mesh

Mesh

NAXJA Forum User
Location
WA
After my engine build I used two 12” flex-a-lite 392’s with a combined CFM of 1840. The flex-a-lites worked fine until I blocked the flow with an AC condenser then it got even worse when the transmission started slipping. So to prepare for the summer and to put off rebuilding my transmission even longer I decided to upgrade the fans. This time around I went with two 12” CSR 1212HD with a combined CFM of 3130.

The reason I used the Flex-a-Lites in the first place was the thickness. I thought the CSR fans would fit but I was wrong. I needed to remove the old mechanical fan pulley and reroute the belt. I found this post to get things going http://www.jeepforum.com/forum/f11/how-replace-mechanical-fan-electric-700226/. I have an 89 with a newer power steering pump and belt tensioner so it turned out a little different.

Part 1: pulley removed and belt rerouted.

Original setup with the Flex-a-Lite 392’s
1imgp0891.jpg



Modified alternator bracket for the belt
3imgp0908.jpg



Old mechanical fan cut off
4imgp0910.jpg



AC bracket mounted
5imgp0915.jpg



Old belt routing
6imgp0902.jpg



New belt routing
7imgp0921.jpg



New CSR 1212HD Fans
8imgp0888.jpg
 
Sweet. Build any kind of shroud? Fan mounts? Wiring?
 
This is the old setup I'm thinking about doing the same thing. The new fans don't quite match up with the old mounts so I have to start over.

imgp0900g.jpg
 
More progress. Since the radiator core is 10x31" I started with a sheet of aluminum 13x31" 0.063" thick. The bottom tabs are finished and the fans have been laid out. I still have some cutting to do.
1imgp0934.jpg


1imgp0941.jpg
 
Are there any numbers available on what CFM the stock fans pull? I've never looked into electric fans, always been happy with the stock stuff, but I might consider it for the buggy.

This looks like a nice installation, but a lot of work. Mind telling us what the motivation was over the stock setup?
 
I don't think there's any official CFM rating on the stock fans. I like having complete control over my cooling system. I set what temperature they turn on and I know there working correctly. I never really liked the stock setup you have one mechanical fan doing all the work then a smaller electric fan that will only turn on if it’s overheating or if the ac is turned on. Another benefit of electric fans is at low rpm they can run at full speed mechanical fans are dependent on engine speed.
 
Mesh: great job on those fans.

My only problem with elimination of the mechanical fan/clutch is what happens when the alternator craps out and you are trying to limp back to civilization on what is left in the battery?

You won't get very far running strictly on the battery with electric fans running. Of course, carrying a spare alternator would eliminate that problem.
 
joe_peters said:
Mesh: great job on those fans.

My only problem with elimination of the mechanical fan/clutch is what happens when the alternator craps out and you are trying to limp back to civilization on what is left in the battery?

You won't get very far running strictly on the battery with electric fans running. Of course, carrying a spare alternator would eliminate that problem.
Click to expand...

Good point, I hope it's cold out and not dark. Usually when the alternator goes you notice it when the battery gets low so I think you’re screwed either way.
 
Mesh said:
Good point, I hope it's cold out and not dark. Usually when the alternator goes you notice it when the battery gets low so I think you’re screwed either way.
Click to expand...

Me, I'm anal on the gauges, always checking them.

How about a low-voltage alarm/warning light?
 
I tried some driving without the belt when I had the bracket removed but I didn't test to see how far I could go. There are too many things that could go wrong. I like to keep everything in good shape and not worry about it.
 
I vaugely remember 5-90 posting CFM numbers on a stock setup but, I don't seem to find it now.
 
I did the whole e-fan mod on my old 96. I'm wanting to do it again on my 99 whenever I get some spare time and cash.


As far as stock requirements, I seem to remember 2000 CFM being the magical number that needed to be achieved to properly cool the ol tractor motor.
 
Mesh said:
I tried some driving without the belt when I had the bracket removed but I didn't test to see how far I could go. There are too many things that could go wrong. I like to keep everything in good shape and not worry about it.
Click to expand...

No belt, no water pump. Things get real hot real quick.
 
I would consider doing it on the buggy, to get a little more power at the top end, and to allow more options on where to mount the radiator.
 
GoJeep, IINM, lists some CFM values on his site- IIRC he did some simple tests to come up with them. It's surely around here somewhere.
 
I removed the bump in the radiator hold down for easier mounting.
imgp0966w.jpg


The fans are now done and mounted. I still need to do some testing.
imgp0971e.jpg
 
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