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This 55037969AB found at 4.7l Jeep GC seems to have a 18,5 inch blade and 1943cfm, but there's a fan clutch listed also, so i think they have both from factory, clutch fan and electric for accessories.
This is the biggest concern i have, i'm looking for a car that doesn't have a fan clutch from factory and only runs electric fans.
The biggest problem is to find out the CFM's, seems you can't find accurate information anywhere.
you had the Volvo fans already, and like you said they will fit our radiator, so i think i will wait and see how yours is running when you made the conversion.
In the meantime, i will try to find info on other fans with big CFM replacement.
Yeah the volvo fan is stand alone, no clutch fan behind it. It was because of the lack of info I decided to build the chamber. I had a guy ping me about a year after that project, the guy built fan installations for some application and mentioned the only thing he would have done differently was to create a grid across the box to measure the flow. I told him the probe I had on the anemometer would have disrupted the flow too much and it did not make sense to go that route. He did mention the data collected across the various fans was a good comparison for what I was after. It showed me the Taurus fan drew the most CFM followed by the straight blade Volvo then the s-blade Volvo.
Since data collection is my profession (electronics test engineer), repeatability was key across each fan. Real world performance is also key for me and those volvo's have not disappointed. I have 2 spares (one has a noisy bearing) in the shed, one of those will find its way into the Dak. But, I can set up a test of both fans on my test box and compare them before the install.
I know you do a lot of research and testing, given the measurements by factory or seller seems unreliable of the different ways they are tested, so many variables.
I know by reading they test the Spal fans different than others, who seems to provide the results on a free flow setup.
I've read other forums and i don't believe in the flex a lite because of lifespan....
If i would go aftermarket, i'd rather go Spal, they seems to be good quality, they are available over here too.
In the long run i think only way to know wich fan is the best is to compare them in a test setup, similar way you're testing.
So if you hook up the fans, you could measure the difference between them, and as long as you set the fans and testing box all the same and compare them right after each other you know wich has the highest CFM rating on you're setup, it doesn't matter if you don't follow any rules of measuring as long as you test in the same setup.
If you read across the forums, the Lincoln mark VIII would be the highest rating, followed by the Ford Taurus, Ford Thunderbird, Jeep, Volvo and lots of others.
The issue is you can't test em all and you have to read or go searching for fans wich come close in dimensions to fit our radiator and look for fan setup for bigger cars/engines who would run fully electric, without the clutch fan from factory.
I can imagine very well you are gonna go with the Volvo fan, because you have this one already, i'm just wandering if the size does matters and if it will be sufficient to cool the engine in extreme conditions without the clutch fan, meaning in traffic stop and go towing on a hot day.
If i read other postings the Jeep fan is around 18 inch and should put out 4000 CFM, but those numbers don't mean anything unless you can compare them in a kind of comparison setup like you made.
I will wait and see if you do the conversion and hear from you hands on if you like it or not.
I think it's all a guessing game, because there are too many variables, i've read postings were everybody is happy with their flex a lite fans on corvettes and others will say there suck....
Every car has a cooling system with another airflow to the radiator, wider or different radiators, shroud or not and so on, some would run the 2 stage fans at 180 and 200 others only have the 1 speed fan, and than there's engine operating temperature, ambient temperature and so on.
Thing is, i'm convinced it works when you drive solo and city stop and go traffic, i'm not convinced if you tow on low speed or in traffic jams....with electric only, but it's all guessing from me.
Hope you can get good results with the Volvo fan, and i might consider to go that route on mine.
Reading your reply reminded me of how Spal did their testing... somewhere I read on their site that they measure a pressure differential. I dont know how that factors into evaluating a fan setup and performance but... I did pick up a few magnahelic gauges over the summer and now have the tools to mostly duplicate their pressure differential setup. Damn.. .now I'm curious.
Also your comments about stop & go traffic... yeah the diesel is not a good example for that one, once fueling is cut to an idle, temps drop pretty good, gas would be different. The worst case I've ever had my ram in was going up over a 3000' summit on a dirt road where speeds were 15~20 mph. I generally wait until it crys for help and temps climb up over 210, then I'll pull over and lower the on temp setting on the controller under the hood (which is just a cheap probe setup). Its always good to go after that.
I think I mentioned this, the next step on the Rams cooling setup is to re-design the shroud to leverage the heat pulled out of the core. right now its wasted, it can be routed towards the airbox to bring up intake temps (100*F is ideal on the diesel.
I do not have the knowledge and equipment to do the tests like you do, and i admire you for that.
Like you said data is everything, but beware of the cost you getting into this.
You've stated earlier you didn't like the 205-210 temperature i'm driving on the Dakota because of the aluminium heads, but like others mentioned, it should be the right operation temperature for this engine.
For myself i wouldn't mind to see 215 to 220 max, but sure as hell i would have to cool it down from that point, i see higher temps on the Jeep guys, but for me 220 is the max.
When i shut mine off when arriving at home my temp usaly is 205 to 210 and when i look for about 15 min later it's at 215, this is normal because there is no more flow through air or coolant of course.
So with 220 i'm confident the heads will hold up, but over it i rather be safe than sorry.
This is why i'm concerned, let's say i hit a trafic jam on a hot day while towing, temps slowly goes up towards and over 220, would i be in time putting up my clutch fan and run it again, before destroying my heads ( valve seats ) ?
For me it's a big ? because i can't find cheap parts over here a used engine will cost me around 3000 dollar and i will probably have to change all the electrics because of the CCD to PCI change.
I could reman the heads myself for most part, but it will take me a long time to have parts and this is my daily driver and only vehicle.
There are numerous vehicles on the road that don't have a mechanical fan, including V-8's, (and larger....) A good electric fan, that moves as much air as possible, with a good shroud, and you will be all set.
My go-to for aftermarket fans is Permacool. One of these should fit inside the existing shroud with a little work, and will pull 2950CFM. You'll want to mount the fan so the blades are as far back as possible, with the back edge of the blades just inside the shroud opening for safety. And, since removal means the fan comes out with the shroud instead of needing to remove the top of the shroud to get the clutch fan out, you can permanently attach the two piece shroud into a one piece unit. The nice thing about electrics is, even at low engine RPMs they can pull the max CFM whereas a clutch fan can only spin as fast as the engine spins. My experience with Permacool is their heavy duty higher rated fans move major air, comparable to what a clutch fan moves, but that's based on the "hand behind the blades" test and not any testing gear.
For other eco-mods, look at a Kamm-back style bed cover. This bed cover would line up with the top of the cab roof, and angle down to the top of the tailgate, which is supposed to help direct air along without any turbulence and return a 10-15 percent mileage improvement. If done right, it might even look nice, although I doubt it.
Kammback-style rear:
Vimes you must visit ecomodder.com (v8cowboy, have a look) LOL, that site is awesome and there is a ton of knowledge there. I had a shell on this truck when I got it, yanked it and sold it. Not a shell guy as I use the bed too much. I will get a jackrabbit tonneau cover for it though at some point. The Ram has one and love it..
that is a slick fan setup, look like the blades are flex blades too. The site mentioned the use of a 30A fuse for startup, a better solution is a thermistor to suppress inrush current. Have a forum buddy who had a relay catch fire while starting up twin tarus fans, too much inrush current. He switched back to a non-electric fan clutch for a bit but then went back to the e-fans and solved the problem. not sure if he used the thermistor or not, have not chatted with him in a bit.
