1 of 10
Bryan Irons
Keeping a Cool Head
2 of 10
Bryan Irons
Keeping a Cool Head
Cooling fan push-through mounting kits like these are not recommended for an off-road vehicle.
3 of 10
Bryan Irons
Keeping a Cool Head
The damage that can occur when using push through mounts.
4 of 10
Bryan Irons
Keeping a Cool Head
An air shear is used to cut the rough outline.
5 of 10
Bryan Irons
Keeping a Cool Head
We use an air nibbler to cut the fan openings.
6 of 10
Bryan Irons
Keeping a Cool Head
Although not necessary, use a file to clean up the rough edges once you are done.
7 of 10
Bryan Irons
Keeping a Cool Head
6mm mounting hardware is drilled and tapped into the aluminum to keep it secure.
8 of 10
Bryan Irons
Keeping a Cool Head
Speed holes and dimple dies for added strength.
9 of 10
Bryan Irons
Keeping a Cool Head
We try and get the biggest relays we can fit, 30A in this case. The Maradyne kit includes instructions and a built-in fuse. They also offer switched controllers as well.
10 of 10
Bryan Irons
Keeping a Cool Head
The finished goods.
Story & photos by Bryan Irons
Creates air flow when the terrain doesn’t allow
Being cheap when it matters has bitten us in the ass for the last time. OK, second last time… maybe third. We had hacked and slashed our way through the cooling system of Stinky Jeep for years and had been let down like a knock off Viagra user once again. In our haste and stupidity, we childishly thought that it was a really simple system that worked from the factory, so why bother stressing over it when doubling the horsepower output of the engine? We even thought that cobbling in some upgrades would make it even better. It sounded great on paper that we swapped out the lousy four blade mechanical fan for junkyard electric units and mediocre control units, in hindsight we could have used that paper to mop up the spewing coolant.
The past cooling system was in trouble with the miniscule 150 hp levels we were pushing, but what was going to happen when we stab in over 400 hp with the Merican Metal Menace? We were smart enough to know when to call for help and we hung the white flag high. After some conversing over the phone, our failures were all too evident to Maradyne’s CJ Clayton who had heard our song and dance before, so we strapped on a set of “big boy” panties and ponied up to the bar for a lesson in air management.
Keeping control of your cooling system is in fact, an exact science. In order to keep your science as precise as possible in the complex world of thermal dynamics, you need to know all the variables. This is where many systems (such as ours) fail miserably as calculating the turbulence of the light bar and winch stacked in front of you rig, or the conductivity of whatever swamp water you’re running as coolant, mess the results up worse then a U.S. presidential nomination.
In light of our inability to count past ten without pulling socks, CJ dumbed it down for us. While aluminum radiators are all the rage; brass/copper units still conduct heat away from your coolant and into the atmosphere better, but are much costlier. Our three core unit would be fine for our intended purposes, but remember, adding another layer of cooling fins only gives miniscule returns as the hot air created from the front tubes do little to cool the remaining. CJ suggested looking at core density and tube dimensions as key factors. Old radiators had the tubes about 14 mm apart; newer units are in the 10 mm range. For an off-road rig that will see high loads and low speeds, the word from every expert we have talked to is “get the largest radiator you can fit.”
Moving the air through the radiator fins was the real reason we rang up CJ at Maradyne. In a nutshell, electric cooling fans are more efficient and create the maximum amount of airflow when you need it the most, at low speeds and high loads. Make sure to look at different manufacturers stats on air flow as no two fans are alike and if the manufacturer muddies up the numbers with fine print, there’s obviously something to hide.
We got a few other tidbits as we pulled the trigger on a new set of rad spinners. Puller fans move more air through the cooling fins in a more even pattern. You can run a pusher as well if you have multiple rows to assist in air movement. CJ always recommends running the largest diameter fan(s) that you can squeeze in. For us, two 12-in Champion series fans with 225-watt motors were the ticket; we were also informed that a shroud should be built to cover the entire area of the radiator when the fans are running.
The Champion series are a quality unit for a multitude of reasons you need to see first hand. With a glass reinforced structure and reversible blades, the structural rigidity in them is second to none. Having a fan housing that flops around in the wind and is susceptible to high temps, will fail quickly and take other parts out with it. The fans we had in the past likely had an IP rating of “Oh no! Not water!” but the IP67 rating of the Maradyne fans allows them to be submerged. In fact, many high performance marine applications use Maradyne cooling fans.
On the electrical side of things, each of our new fans had the potential of drawing 20 amps each, so we were glad we ditched the stock alternator for an MSD 160 Amp one wire piece… even if it was all chromed out. We also scored pair of fan relays from Maradyne to hook up to a simple on/off system. After may years of running “variable speed” fan controllers, we were running low on fingernails to bite hoping that the controller wouldn’t fail… again. A simple relay switched on and off by our Holley Terminator EFI system at different temperatures was the final fix.
With our “thank-you” and call complete with CJ at Maradyne, we had to wait for a box of fans and relays to be dropped at the door. After their arrival, it was now time to start fabbin’ a shroud. In the past we had used the cheap “mounting ties” that push through the radiator fins and lash the fans directly to the radiator itself. After all the jostling around on back road, our fins were getting bent like magazine editors at a performance review. Some time and a small pic got them all back in shape and we considered ourselves lucky as springing a leak could have easily happened. Our shroud is nothing special but works as intended. A flat piece of aluminum sheet and some time with a cutting tool resulted and a sturdy mount with enough gap to ensure a smooth flow of air through our heat exchanger.
CJ had given us some good pointers to keep the fans moving as much air as smoothly as possible. We punched a few extra holes in the back to allow more air to flow through the rad when at speed. This also added some extra strength to the flimsy shroud by using a dimple die to create a flange in the edge. This mod is a double edge sword as the open holes also allow air to be circulated in the reverse direction when the fan is running. The fix for this is to mount a flap door to the backside of the vents to essentially create a “one-way valve”. We also made sure to keep the fan edges about 15 mm back from the radiator fins to ensure air can be drawn from the entire surface of the radiator.
When having problems, we always recommend listening to the experts in their field… but some times we’re too dense to take our own advice. After some time, we came to our senses and it paid off once again. Between the previously installed Daystar hood vents, the cooling fans and advice from Maradyne, and ditching the premise of just trying to prop up the cooling system, our rig now lumbers down the trail in 35°C heat and stays at a rock solid 90°C all day long. So, like any addicted chain smoker will tell you; do as we say, not as we do!
Maradyne Fans - www.maradynehp.com