Turbo Jeep cooling issue

[Steel City 06]

Here's the spec sheet for the fans. I'm kind of ignorant on how to understand it.

Those fans are most certainly undersized for your application. Assuming similar static pressure drop to my fan combo (210 Pa, or about 21.5 mm H2O), you are only getting about 400 CFM per fan through the radiator for about 800 CFM total, which is likely going to be insufficient in a lot of cases, especially if you add AC on top of that. Add a turbo and I guarantee that would cause issues. You basically have enough fan to run the AC and not much more.

The SPAL 19" fan should pull triple that airflow even with the radiator, condenser, and 3rd cooler stacked on it. I estimate about 2,800 CFM in my setup.

I would recommend giving the Explorer fan or the SPAL Camaro fan a shot. Both should have way more than enough airflow for your needs.

 

[Steel City 06]

I've definitely thought about that, my oil pressure seems to drop to about 25-30 after warmup since I've installed the kit. I'm running 10-30 and it seems to have helped a little. Maybe my oil is getting too hot.

Super easy air to water oil cooler:
https://wranglertjforum.com/threads...ost-oil-cooler-heater-in-a-4-0-and-why.73481/

It's also simultaneously an oil heater, so massively improves oil life and gives a small gas mileage boost.

 

[MikeE024]

I've definitely thought about that, my oil pressure seems to drop to about 25-30 after warmup since I've installed the kit. I'm running 10-30 and it seems to have helped a little. Maybe my oil is getting too hot.

Remember, your issue is in idle with the AC on, so I wouldn’t be worried about the oil in idle heating up the engine coolant too much. If anything, I’d be more worried about your coolant heating up the oil too much (Mobil 1 and Redline both stated in BITOG to stay under 250*). Still shouldn’t be a problem.

Fwiw, I run Redline 5w-30 bc it has a low Noack and does well with turbo engines. No need to run their 10w-30 bc the Noack isn’t any lower. Enough on that.

If your fan setup and thermostat are working properly, which is sounds like they are, then I’d probably try the 19” brushless spal. This makes sense if you are good when putting more air through the radiator by driving around. You may just need serious air pulling through the grill with your setup.

 

[Steel City 06]

What is the amp or wattage rating on you current Spal fans? That is a much better indication of power than CFM.

Also, just to put it in perspective, the surface area of a single 16” fan is about 25% larger than two 10” fans.

Power is only part of the equation, but can tell you a decent amount. Surface area is incredibly important too.

Larger fans tend to be more efficient at moving air. My puny 19" fan takes 835 watts to run and yet probably pulls less than 6,000 CFM if it was in free air. Meanwhile, a Big Ass Fans 30' ceiling fan can pull 368,098 CFM using 2,000 watts. Even running it at 800 watts, the 30' fan still pulls 40X as much air as the tiny 1.5' fan does at the same power.

Larger surface area also means more area for heat exchange, which I think is a huge thing people tend to overlook. If your fans only cover 40% of your radiator, even if you somehow pulled the air through at Mach 1, you're still not going to see as much heat rejection as if you covered 100% of the radiator at a much lower airspeed.

 

[MikeE024]

Power is only part of the equation, but can tell you a decent amount. Surface area is incredibly important too.

Larger fans tend to be more efficient at moving air. My puny 19" fan takes 835 watts to run and yet probably pulls less than 6,000 CFM if it was in free air. Meanwhile, a Big Ass Fans 20' ceiling fan can pull 368,098 CFM using 2,000 watts. Even running it at 800 watts, the 30' fan still pulls 400X as much air as the tiny 1.5' fan does at the same power.

Larger surface area also means more area for heat exchange, which I think is a huge thing people tend to overlook. If your fans only cover 40% of your radiator, even if you somehow pulled the air through at Mach 1, you're still not going to see as much heat rejection as if you covered 100% of the radiator at a much lower airspeed.

That’s pretty incredible man. Thanks for sharing.

 

[Mrmassdestruction]

Thanks for sharing some of your research, it's very insightful. Do you by chance know the thickness of the camaro fan? Worst case I can go back to the stock radiator, it probably cools better anyways. I'm just tired of throwing money at this thing.

 

[Mrmassdestruction]

Does anyone have any experience with delta current control fan controllers? I already bought one and it's just collecting dust. I wonder if it's compatible with the camaro fan.

 

[MikeE024]

Does anyone have any experience with delta current control fan controllers? I already bought one and it's just collecting dust. I wonder if it's compatible with the camaro fan.

I can only assume it’s not compatible since @Steel City 06 mentioned finding a controller to work with the OEM fan since most don’t work. But, he’d be the guys to ask.

Here’s his thread

 

[Mrmassdestruction]

Okay, I just went through the thread. So with the camaro fan mounted to the oem shroud I presume it shouldn't stick out much further. I'm definitely going to consider this option. I already swapped to a 160 Amp Durango alternator so hopefully I can power it sufficiently. @Steel City 06 , do you have any more info on how you secured the fan to the shroud? I appreciate everyone's help!

 

[Brianj5600]

I don't remember seeing any posts about pulling air that has already passed through the radiator or heated from under the hood. If the radiator is sealed to the grill shell, only ambient air coming through is 7 slots. That gives the coolest air available.

 

[Steel City 06]

Okay, I just went through the thread. So with the camaro fan mounted to the oem shroud I presume it shouldn't stick out much further. I'm definitely going to consider this option. I already swapped to a 160 Amp Durango alternator so hopefully I can power it sufficiently. @Steel City 06 , do you have any more info on how you secured the fan to the shroud? I appreciate everyone's help!

Basically I just cut the Camaro shroud profile down to the outer of the two rings, and then just fished a nut and washer in between the two. A couple washers to space it out from the TJ shroud (the 2nd ring is maybe 1/4" smaller diameter than the TJ's shroud). Repeat for every stay, maybe double it.

A blind rivet and a fender washer might also do the job.

 

[Steel City 06]

Does anyone have any experience with delta current control fan controllers? I already bought one and it's just collecting dust. I wonder if it's compatible with the camaro fan.

Took a look at their website. Those fan controllers look like they are intended to control brushed fans by basically switching the power supply on and off at a high frequency. The OEM SPAL fans are different - you just need a PWM to ground signal of a few milliamps.

It might be possible to use that controller to generate a PWM signal by using a relay to invert the PWM signal to ground and some pull-up or pull-down resistors, but it's certainly complex and definitely not guaranteed to work. Plus, the inverted logic of the OEM SPAL fans basically means you'll be building a very complex circuit. (At that point, you're better off just using an Arduino.)

The Lingenfelter controller I know will work. I actually originally intended to use a Rugged Circuits Arduino, but just haven't had time to get that figured out yet.

 

[Mrmassdestruction]

Very interesting, I might have to give this a shot, I mean if it's good enough for a 600+ hp v8 surely it can cool my 4.0.

Edit: parts are ordered. Everything should be here next week.

 

[Mrmassdestruction]

Fan controller came in a little early, definitely seems to be high quality.

 

[Mrmassdestruction]

Fan came in.

 

[Mrmassdestruction]

OK, so I was planning on doing a small scale test outside of the jeep to see if my setup will work, didnt get around to it. One thing I didn't consider is the ac override, it seems that the override input for the lingenfelter is only max duty cycle. @Steel City 06 did you happen to set up an ac override with your controller?

 

[willis36]

Does anyone have any experience with delta current control fan controllers? I already bought one and it's just collecting dust. I wonder if it's compatible with the camaro fan.

Back when I ran an electric fan I had one of those and they work amazing!! Put that dude in for sure. Fan hardly ever ran on full speed, and it has a slow start feature so it doesnt pull much load when it kicks the fan on. I had mine on a old 17 inch volvo fan and never had overheating problems. I bumped it with a wrench accidentally and fried it, so I just put the mechanical fan back on.. If not for that I would still be running it

 

[Steel City 06]

OK, so I was planning on doing a small scale test outside of the jeep to see if my setup will work, didnt get around to it. One thing I didn't consider is the ac override, it seems that the override input for the lingenfelter is only max duty cycle. @Steel City 06 did you happen to set up an ac override with your controller?

I haven't had time to experiment, but I was considering using a Zener diode as a sort of minimum override for when AC is turned on. Basically it would clamp the temperature sensor to a max voltage drop, causing the fan to run at that speed or a higher speed if demanded by the temp sensor.

 

[Mrmassdestruction]

Interesting, sounds like it would work. I guess with 100% fan my ac should be working pretty good.

 

[Mrmassdestruction]

It may look like mad science but I was able to get the fan running with an arduino and a temp sensor. That means I can run any control scheme I want. I was thinking about implementing pid control what do you think @Steel City 06?