Novak Conversions Jeep Wrangler TJ radiator

Cooling fan upgrade comparison: Explorer 11-blade fan and HD clutch versus SPAL 19" 850-watt electric brushless fan

Got the Camero fan in today but those sores on my leg aren't healed yet so I'm waiting to rip the Jeep apart.

20250904_172705.jpg


20250904_172723.jpg


Once I've got the radiator removed and the 300 watt SPAL fan off I'll try and document what I do to make it fit if I can.
 
Turns out if you really want cold AC, you just need a little propane...

32°F coming out of the vents, 76°F going in the intake, moderate humidity, 2,000 RPM, max blower speed and max fan speed.

All I did was swap the R134A with a R290/600a blend and put in an adjustable low pressure switch. A/C is now stupid cold and also uses less energy

View attachment 616886

I Want the download on this - Did you just add a can of Duracool 12a?

Edit: if one keeps reading and doesn't just get excited - they get a great description here: https://wranglertjforum.com/threads...att-electric-brushless-fan.78963/post-1781452
 
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Yes, I used an adjustable low pressure switch, in particular this one:
https://www.amazon.com/dp/B003R42YMS?tag=wranglerorg-20

Not mandatory but it might be possible to tune it slightly colder with an adjustable switch. I was able to get a few extra degrees out of it. Biggest caveat is to not adjust the pressure setpoint so low that ice accumulates on the evaporator.

Threads right on to the OEM line. Note you do not need to discharge the AC system to replace the switches.

how did you wind up setting the adjustable low side switch to avoid icing? Just kinda guess and see if your feet get wet later, or?
 
how did you wind up setting the adjustable low side switch to avoid icing? Just kinda guess and see if your feet get wet later, or?

Basically, hold the engine at about 2,500 RPM, engine fan max speed, HVAC fan lowest speed. Ultra humid day helps. Basically just watching to see the line going to the evaporator inside the engine bay. If you're close, it will ice up and then thaw every few seconds as the compressor cycles. Once the ice cycle is minimal to non-existent, you're pretty much set.

If you get an effect where using your AC causes airflow to drop off over the course of an hour, then you're still building ice and you need to back it off even more.
 
Basically, hold the engine at about 2,500 RPM, engine fan max speed, HVAC fan lowest speed. Ultra humid day helps. Basically just watching to see the line going to the evaporator inside the engine bay. If you're close, it will ice up and then thaw every few seconds as the compressor cycles. Once the ice cycle is minimal to non-existent, you're pretty much set.

If you get an effect where using your AC causes airflow to drop off over the course of an hour, then you're still building ice and you need to back it off even more.

Do you know offhand what pressure the factory switch opens at?

28psi would ensure you never had any frost, but you could probably go a little lower than that and let it form a small enough amount that it melted during the off cycle.
 
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Do you know offhand what pressure the factory switch opens at?

28psi would ensure you never had any frost, but you could probably go a little lower than that and let it form a small enough amount that it melted during the off cycle.

Not 100% sure, but RockAuto shows 27/45 PSI being common.

I'm pretty sure I've gone a fair amount below that, but have no way to measure. The optimal amount will depend on the mass of refrigerant used as well as the exact propane to butane (or isobutane) blend used in the refrigerant. More butane (or especially isobutane) versus propane will mean lower pressures required.
 
welp, it works - its 70* ambient here right now, so hard to tell if the A/C is that much colder. But if you turn the low side adjustment down really much at all she will ice the lines quite quickly. Brilliant upgrade. @Steel City 06 - this almost deserves its own thread.

I went ahead and pulled my old Aux. fan out while I was there in preparation for the pending Camaro install.
 
Not 100% sure, but RockAuto shows 27/45 PSI being common.

I'm pretty sure I've gone a fair amount below that, but have no way to measure. The optimal amount will depend on the mass of refrigerant used as well as the exact propane to butane (or isobutane) blend used in the refrigerant. More butane (or especially isobutane) versus propane will mean lower pressures required.

Oh, of course. I forgot we were talking about the propane/isobutane mix. 28 psi would be for 134a and if they targeted the blend to be a 134a drop-in then they could have matched that exactly, but they may not have if there were competing priorities.

I'm used to working with gases with full, published property data, this is weird. 🤣
 
Well, add me to the list of happy customers.

I tried a few combinations of PCM controlling the fan I am still optimistic that its possible, but at $50 a credit and needing at least 2 credits...... I'm taking a pause perusing that right now. Because I am a cheap bastard, I wound up using the Widget man PWM Fan controller, I purchased it through Ebay, but you can save a buck purchasing direct from him. Add this with a T-tap of your choosing to the positive line of your ECT sensor (like an orange or yellowish color if I remember correctly) and set the dip switches as following:

1:Hi, 2:Hi, 3:Lo, 4:Lo, 5:Lo, 6:Hi, 7:Lo.

This sets the correct fan polarity, sensor settings and puts the A/C or Switch override to +50% instead of MAX which given the power of this fan feels most fitting.

For the instillation I followed the trimming outlined in The_Walrus's post above I then use 5/16th bolts and nuts with 2 washers between the GM shroud and the Jeep shroud for spacing. I originally pushed the fan to far forward (close to the radiator) and the fan-blades were warping forwards and contacting the Jeep shroud when the fan hit 50%+ RPM. (see below photos)

IMG_9055.JPG

IMG_9056.JPG

^ here you can see the markings on the case for + and - Fan leads from the video linked earlier in this thread.

IMG_9148.JPG

^ I used Red Loc-tite to help ensure the bolts don't back out with the vibrations. ABS Locker nuts are to large to fit in the captive space.

IMG_9151.JPG

IMG_9150.JPG

^ Heres where the fan was contacting. note you need MORE spacing than seen above.

Here are some pictures of the working install. I just used adhesive tape to mount the fan controller. I imagine i will have to update that to a wrap-around zip-tie or bolt of some part as heat becomes a factor. I used High-Amp Power pole connectors and 8Ga wire , if I did it again, I would use the Female OEM GM Connector for a cleaner install, but I wasn't able to find it in-time.

IMG_9193.JPG

^ NOTE! you will need to seal these dip switches with RTV or Di-electric to make the controller water-proof. I haven't done that at the time of this photo.

IMG_9195.JPG

IMG_9196.JPG


I set the low trip point at 180*, and the high trip point at 220* - this seems to keep the fan relatively quiet while keeping the jeep at 190* give or take in what is currently 40* weather. I may adjust these as summer comes around, but for now they seem to allow the jeep to warm up and maintain closed-loop op temp with plenty of headroom for cooling. I am concerned I may be over-cooling, but without a Rad. Temp sensor it's hard to tell. either way, I would rather over cool than over heat.

I have noticed a 1-2MPG increase across the board city and hwy (measured at the pump) , and I can now get 17.5MPG on the HWY (per my ultra-gauge)! (previously the best i could manage was about 14.5-15)
IMG_9188.JPG


I have also noticed substantially reduced warm-up times with the fan not cooling until 180*. The jeep rev's much faster contributing to a more "sporty" driving experience and makes life better if you like downshifting. I wouldn't say theres more power - but she feels more on edge and "perky". The interior is notably quieter. I can hear the fan when it’s running in over-ríe (call it 50%+) but even then it’s still quieter than the stock fan was. I may look into isolating the aground mount to help even more with noise transfer.

All in all this fan moves a TON of air, my finely calibrated hairline estimates 100% on the E-fan is about the same as 1200-1500 RPM on the mechanical fan. I am excited to see how the E-fan holds up in the summer, in combination with @Jezza's water-pump/ fan overdrive pulley hopefully I can keep this poor jeep below *220 idling with the A/C on in the summer.
 
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Well, add me to the list of happy customers.

I tried a few combinations of PCM controlling the fan I am still optimistic that its possible, but at $50 a credit and needing at least 2 credits...... I'm taking a pause perusing that right now. Because I am a cheap bastard, I wound up using the Widget man PWM Fan controller, I purchased it through Ebay, but you can save a buck purchasing direct from him. Add this with a T-tap of your choosing to the positive line of your ECT sensor (like an orange or yellowish color if I remember correctly) and set the dip switches as following:

1:Hi, 2:Hi, 3:Lo, 4:Lo, 5:Lo, 6:Hi, 7:Lo.

This sets the correct fan polarity, sensor settings and puts the A/C or Switch override to +50% instead of MAX which given the power of this fan feels most fitting.

For the instillation I followed the trimming outlined in The_Walrus's post above I then use 5/16th bolts and nuts with 2 washers between the GM shroud and the Jeep shroud for spacing. I originally pushed the fan to far forward (close to the radiator) and the fan-blades were warping forwards and contacting the Jeep shroud when the fan hit 50%+ RPM. (see below photos)

View attachment 661140
View attachment 661141
^ here you can see the markings on the case for + and - Fan leads from the video linked earlier in this thread.

View attachment 661142
^ I used Red Loc-tite to help ensure the bolts don't back out with the vibrations. ABS Locker nuts are to large to fit in the captive space.

View attachment 661143
View attachment 661144
^ Heres where the fan was contacting. note you need MORE spacing than seen above.

Here are some pictures of the working install. I just used adhesive tape to mount the fan controller. I imagine i will have to update that to a wrap-around zip-tie or bolt of some part as heat becomes a factor. I used High-Amp Power pole connectors and 8Ga wire , if I did it again, I would use the Female OEM GM Connector for a cleaner install, but I wasn't able to find it in-time.

View attachment 661146
^ NOTE! you will need to seal these dip switches with RTV or Di-electric to make the controller water-proof. I haven't done that at the time of this photo.

View attachment 661147
View attachment 661148

I set the low trip point at 180*, and the high trip point at 220* - this seems to keep the fan relatively quiet while keeping the jeep at 190* give or take in what is currently 40* weather. I may adjust these as summer comes around, but for now they seem to allow the jeep to warm up and maintain Open-loop op temp with plenty of headroom for cooling. I am concerned I may be over-cooling, but without a Rad. Temp sensor it's hard to tell. either way, I would rather over cool than over heat.

I have noticed a 1-2MPG increase across the board city and hwy (measured at the pump) , and I can now get 17.5MPG on the HWY (per my ultra-gauge)! (previously the best i could manage was about 14.5-15)
View attachment 661149

I have also noticed substantially reduced warm-up times with the fan not cooling until 180*. The jeep rev's much faster contributing to a more "sporty" driving experience and makes life better if you like downshifting. I wouldn't say theres more power - but she feels more on edge and "perky". All in all this fan moves a TON of air, my finely calibrated hairline estimates 100% on the E-fan is about the same as 1200-1500 RPM on the mechanical fan. I am excited to see how the E-fan holds up in the summer, in combination with @Jezza's water-pump/ fan overdrive pulley hopefully I can keep this poor jeep below *220 idling with the A/C on in the summer.

Nice work. Is that the Camaro fan?
 
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Well, add me to the list of happy customers.

@Jezza's water-pump/ fan overdrive pulley hopefully I can keep this poor jeep below *220 idling with the A/C on in the summer.
I recently picked up a new GM fan for cheap so I'll most likely be doing this electric fan conversion too ! I'd like that quicker revs for when I'm ripping around 😁 (which happens all the time)
I've noticed that my jeep wouldn't go past 189* in this sub 55* degree weather lol
I also have Jeremy's waterpump OD pulley and I have to beat on it hard to make it touch 191*
I had my header glowing after ripping through the back roads I go through and it finally touched 195* after letting it idle to somewhat heatsoak. I was impressed! (In sub 55* weather)

The most I've seen IIRC was 228/230ish * when it was well over 112* here in Texas in a HEB parking lot when it first opened up! A/c on at full blast for an hour with cars infront of me,Stock pulley would've lead me to just turn the jeep off.
 
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Well, add me to the list of happy customers.

I tried a few combinations of PCM controlling the fan I am still optimistic that its possible, but at $50 a credit and needing at least 2 credits...... I'm taking a pause perusing that right now. Because I am a cheap bastard, I wound up using the Widget man PWM Fan controller, I purchased it through Ebay, but you can save a buck purchasing direct from him. Add this with a T-tap of your choosing to the positive line of your ECT sensor (like an orange or yellowish color if I remember correctly) and set the dip switches as following:

1:Hi, 2:Hi, 3:Lo, 4:Lo, 5:Lo, 6:Hi, 7:Lo.

This sets the correct fan polarity, sensor settings and puts the A/C or Switch override to +50% instead of MAX which given the power of this fan feels most fitting.

For the instillation I followed the trimming outlined in The_Walrus's post above I then use 5/16th bolts and nuts with 2 washers between the GM shroud and the Jeep shroud for spacing. I originally pushed the fan to far forward (close to the radiator) and the fan-blades were warping forwards and contacting the Jeep shroud when the fan hit 50%+ RPM. (see below photos)

View attachment 661140
View attachment 661141
^ here you can see the markings on the case for + and - Fan leads from the video linked earlier in this thread.

View attachment 661142
^ I used Red Loc-tite to help ensure the bolts don't back out with the vibrations. ABS Locker nuts are to large to fit in the captive space.

View attachment 661143
View attachment 661144
^ Heres where the fan was contacting. note you need MORE spacing than seen above.

Here are some pictures of the working install. I just used adhesive tape to mount the fan controller. I imagine i will have to update that to a wrap-around zip-tie or bolt of some part as heat becomes a factor. I used High-Amp Power pole connectors and 8Ga wire , if I did it again, I would use the Female OEM GM Connector for a cleaner install, but I wasn't able to find it in-time.

View attachment 661146
^ NOTE! you will need to seal these dip switches with RTV or Di-electric to make the controller water-proof. I haven't done that at the time of this photo.

View attachment 661147
View attachment 661148

I set the low trip point at 180*, and the high trip point at 220* - this seems to keep the fan relatively quiet while keeping the jeep at 190* give or take in what is currently 40* weather. I may adjust these as summer comes around, but for now they seem to allow the jeep to warm up and maintain closed-loop op temp with plenty of headroom for cooling. I am concerned I may be over-cooling, but without a Rad. Temp sensor it's hard to tell. either way, I would rather over cool than over heat.

I have noticed a 1-2MPG increase across the board city and hwy (measured at the pump) , and I can now get 17.5MPG on the HWY (per my ultra-gauge)! (previously the best i could manage was about 14.5-15)
View attachment 661149

I have also noticed substantially reduced warm-up times with the fan not cooling until 180*. The jeep rev's much faster contributing to a more "sporty" driving experience and makes life better if you like downshifting. I wouldn't say theres more power - but she feels more on edge and "perky". The interior is notably quieter. I can hear the fan when it’s running in over-ríe (call it 50%+) but even then it’s still quieter than the stock fan was. I may look into isolating the aground mount to help even more with noise transfer.

All in all this fan moves a TON of air, my finely calibrated hairline estimates 100% on the E-fan is about the same as 1200-1500 RPM on the mechanical fan. I am excited to see how the E-fan holds up in the summer, in combination with @Jezza's water-pump/ fan overdrive pulley hopefully I can keep this poor jeep below *220 idling with the A/C on in the summer.

Great job & clean install. I've got the same controller but I was also going to try looking at the Hemi PCM and see if there isn't a electric fan signal in there somewhere. Just haven't done it yet.
 
I recently picked up a new GM fan for cheap so I'll most likely be doing this electric fan conversion too ! I'd like that quicker revs for when I'm ripping around 😁 (which happens all the time)
I've noticed that my jeep wouldn't go past 189* in this sub 55* degree weather lol
I also have Jeremy's waterpump OD pulley and I have to beat on it hard to make it touch 191*
I had my header glowing after ripping through the back roads I go through and it finally touched 195* after letting it idle to somewhat heatsoak. I was impressed! (In sub 55* weather)

The most I've seen IIRC was 228/230ish * when it was well over 112* here in Texas in a HEB parking lot when it first opened up! A/c on at full blast for an hour with cars infront of me,Stock pulley would've lead me to just turn the jeep off.

In this cooler Texas weather I am seeing 185-195 in everything from cruising to driving like a Jeremy Clarkson with a chicken in the passenger seat. I seem to gain the most temp sitting at idle after a high load HWY run. She actually keeps pretty cool in "spirited" driving. In the summer I sit around 210 cruising and 215 sitting. I get nervous when she starts to climb up towards 220 and beyond, by the time I hit 225 I am concerned. I have seen 228-230 briefly on startup, t that doesn't concern me to much so long as it goes down in the first min or two. what worries me is climbing up past 220 when cruising at 80 with the A/C on.
 
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In this cooler Texas weather I am seeing 185-195 in everything from cruising to driving like a Jeremy Clarkson with a chicken in the passenger seat. I seem to gain the most temp sitting at idle after a high load HWY run. She actually keeps pretty cool in "spirited" driving. In the summer I sit around 210 cruising and 215 sitting. I get nervous when she starts to climb up towards 220 and beyond, by the time I hit 225 I am concerned. I have seen 228-230 briefly on startup, t that doesn't concern me to much so long as it goes down in the first min or two. what worries me is climbing up past 220 when cruising at 80 with the A/C on.

Yep, the real testing and review comes during the summer.

My old setup was always fine in the cooler AZ temps, but the current setup has me where I need to be in extreme temps.
 
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In this cooler Texas weather I am seeing 185-195 in everything from cruising to driving like a Jeremy Clarkson with a chicken in the passenger seat. I seem to gain the most temp sitting at idle after a high load HWY run. She actually keeps pretty cool in "spirited" driving. In the summer I sit around 210 cruising and 215 sitting. I get nervous when she starts to climb up towards 220 and beyond, by the time I hit 225 I am concerned. I have seen 228-230 briefly on startup, t that doesn't concern me to much so long as it goes down in the first min or two. what worries me is climbing up past 220 when cruising at 80 with the A/C on.

I had a 99 XJ, and the computer would turn the electric fan on at 220. So that's full operating temp, not hot or anything to worry about. I didn't worry at all if it was 230 or less.
 
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Novak Conversions Jeep Wrangler TJ radiator