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Cooling System Basics and Radiator Buyers Guide - Hot and Bothered

Posted in How To: Engine on April 15, 2015
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OK, so the cooling system on your truck is not nearly as sexy as those new shocks or lights. The cooling systems on your rig, however, are much more complicated than it may seem. It’s also far harder to appreciate the importance of your cooling system compared to how cool those new shocks are.

So why go to the expense and effort to upgrade your cooling system? Well, quite honestly, any cooling expert will tell you that a purpose-built cooling system will help achieve optimal engine performance while protecting your not so inexpensive equipment, helping you to avoid situations that lead to equipment failure and unnecessary wear and tear.

Chris Paulsen of C&R radiators says, choosing the correct cooling system components for your application, be it casual off-roading to full blown racing, starts with understanding certain cooling basics. As Paulsen has eloquently written in his website based “Cooling 101,” there are several factors to consider.

Actually, there are a lot of factors, especially when talking about off-road vehicles. From cooling configurations, contributors to heat in the system, the core construction itself, including material, type of welding, fin pitch, fins per inch, tube spacing, overall thickness in comparison to frontal surface area, water flow, airflow, and application. Adding in the harshness of the off-road environment and how a vehicle can be driven hard at even low speeds let alone wide open along a power line road, and you get the idea that there is much more to this cooling thing than meets the eye.

While engines have steadily improved over time, they still have some inefficiency in their design, which at its basic is changing chemical power (fuel) to mechanical power. Burning fuel creates heat obviously, but how the engine is tuned needs to be evaluated as well. Running advanced timing and a lean fuel mixture creates big power, but also higher than normal temps. Something like a restrictive exhaust system can place high demands on the system.

Even something as trivial as a leaking radiator cap can cause heat in the system to increase. We’re sure everyone knows that modern cooling systems are pressurized. Pressurizing the system increases the boiling point with every psi of pressure, increasing boiling point 3 dF at sea level. That means any leaks raise the temperature of the fluid even if all other factors are within spec.

You may never have thought about it, but it’s possible for an engine to run too cold. With the advent of EFI and computer-regulated engines such as the LS series, gone are the days of simply removing the thermostat. In fact, if the water temp isn’t sufficiently high enough, then the computer won’t “kick on” and the engine won’t produce its full amount of power. Modern vehicles need to run within a specific temperature range and if they don’t get hot enough, they won’t run well. Too hot is obviously not good, but too cold isn’t good either.

Understanding your demand will guide your choices in system configuration and construction. Beyond OE open systems there are two other types of cooling systems. The first is a closed system with a surge tank equipped with a radiator cap and fill neck, the second being a pressurized system with an accumulator that acts as an air spring, a pressure relief valve, and a quick disconnect to add pressure that exceeds normal temperature expansion.

System configuration is not the end of the discussion, however, as core construction also comes into play. Paulsen says, an all-aluminum core is preferable as it eliminates lead solder, which slows heat conduction. They are also usually TIG welded, allowing for ease of customization, but perhaps the best part is that they are up to 30 percent lighter than older brass-style radiators.

Each system is different, but factors such as fins per inch (FPI) and tube spacing affect heat dissipation. You’d think that high FPI would work well in race applications, but FPI in off-road applications may be as little as 12 FPI to allow for dispersal of debris. Paulsen further suggests that low FPI in off-road applications may not be the best solution but may be better handled with a proper grille to deflect dirt and mud to allow a higher FPI for better heat transfer.

As your system is just that, a system that works as a whole, you have to consider the implications of airflow and water flow. While core thickness may increase cooling capacity, the decrease in airflow volume and velocity needs to be considered. A continual source of ambient air needs to be supplied to the radiator with high pressure in the front and low pressure behind. This is where grille opening, duct work, airboxes and high CFM electric fans come into play.

Water flow is determined by the pump. However, it’s combined with tube area to determine fluid velocity. Pressure and velocity are two different things, and then there’s water turbulence, which decreases heat rejection. Flow rate and core size can be determined to maximize heat transfer. However pressure drop/changes must be taken into account. Lastly, fluid retention is accomplished with the use of recovery tanks, radiator caps, and fill neck. The fluid retention systems also add the necessary benefit of keeping air out.

There are a lot of determining factors when thinking about how to keep your engine cool, that’s why it’s good to talk to a cooling professional about your vehicle and what it is that you’re going to be doing. They will need to know what performance changes you have done and what typically type of driving you do. Then they can suggest, or even build you, the perfect type of cooling system that you need. Cooling your ride isn’t rocket science, but it is science nonetheless.

We have assembled a buyer’s guide of what some of the best radiator and cooler builders are building. These may not be on your vehicle per se, but these builders probably either offer a pre-built unit for it or they can build a unit just for your vehicle using the knowledge they’ve gained and the input you give them.

Radiators

C&R Racing
Off-Road Radiator
Whether beating through the extreme conditions of the desert or off-road closed course racing the C&R Off-Road Radiator is custom designed to your application. C&R offers complete cooling systems for these high horsepower, low airflow vehicles.
C&R Racing
317.293.4100, www.crracing.com

C&R specializes in different mounting situations for the harsh environment of off-road racing. The radiators are custom-built to the height, width, fitting layout, and mounts specified by your application with a heat exchanger option. Standard and custom radiators are available.

CFR Performance
The CFR EMC=3 modular cooling system is capable of cooling just about anything you can throw at it. The EMC=3 has a huge 3½-inch-thick massive cooling core with three rows of 7/8-inch high volume and high-flow heat transfer tubes with an optimized 15 fins per inch of cooling power. The EMC=2 has an oversized 2¼-inch-thick cooling core with two rows of 1-inch high volume and high-flow heat transfer tubes with an optimized 15 fins per inch of cooling power.
CFR Performance 800.838.8024, www.cfrperformance.com

These advanced cooling modules also include eight separate 3/8-inch x 24 threaded bungs for attaching optional mounting bracket kits and hardware allowing the unique option of using this radiator as a traditional top and bottom tank design or the modern crossflow design.

C&R Racing
Jeep Radiator
This radiator utilizes our all-aluminum race-proven 36mm closed-tube center core. With features like water jetted mounts for the factory fan/shroud including overflow tank, A/C condenser, and transmission oil cooler allow it to install same as factory.
C&R Racing
317.293.4100, www.crracing.com

Off-road or on-road this new C&R Racing radiator will keep your engine cool and get you there and back.

Champion Cooling Systems
Radiator #716
Champion’s 716 radiator is the radiator of choice for ’73-91 Chevrolet C/K trucks, Blazers, and Suburbans with V-8 engines. It also fits in corresponding GMC trucks and SUVs. This popular crossflow radiator is available in a two-row configuration with 1-inch tubes, or our standard two, three, and four-row versions with either 3/4-inch or 5/8-inch tube spacing, depending on part number.
Champion Cooling Systems
951.245.9464, www.championcooling.com

Champion also offer a fan/shroud configuration for enhanced looks and extra cooling power. All Champion radiators are backed by a limited lifetime warranty.

CBR
Pro Class Radiator
Take it from the pros; CBR Performance Products specializes in manufacturing high-performance custom all-aluminum, off-road radiators. Our radiators feature a 100 percent all-aluminum core. All CBR radiators feature the unique wider tube configuration and revolutionary louver fin design angle, allowing the best cooling performance in the most extreme conditions imaginable.
CBR
951.245.2900, www.cbrperformance.com

All CBR radiators are 100 percent TIG welded and made from aircraft-grade aluminum. Ingenuity, durability, strength, and performance are built into all CBR radiators for your everyday demands. This Pro Class Radiator features two in-tank heat exchangers and two air-to-oil coolers located at the bottom of the radiator.

Champion Cooling Systems
Radiator #433
Looking for an aluminum replacement radiator for your Ford F-Series pickup or Bronco? Look no further than our 433. This stout radiator is available in a two-row configuration with 1-inch tubes, or our standard two-, three-, and four-row versions with either 3/4- or 5/8-inch tube spacing, depending on part number. The 433 will fit in trucks and SUVs with V-8 engines ranging from 1968 to 1979 and easily cool upward of 800 hp.
Champion Cooling Systems
951.245.9464, www.championcooling.com

Champion also offers a fan/shroud configuration for enhanced looks and extra cooling power. All Champion radiators are backed by a limited lifetime warranty.

Champion Cooling Systems
Radiator #1165
This radiator is designed specifically for ’83-94 Ford F-Series trucks with diesel engines. Available in two-, three-, and four-row cores, this beast of a radiator will keep your Diesel powerplant running at its optimum temperature.
Champion Cooling Systems
951.245.9464, www.championcooling.com

Champion’s radiators are made from the highest grades of aluminum, are 100 percent TIG-welded (no epoxy) with high-density furnace-brazed cores and louvered fin technology. Available in two, three, and Monster Series four-row cores, the radiators can cool even the largest engines (over 1,000 hp). We also offer a line of low profile as well as high-performance fans and fan shrouds for extra cooling power and a truly custom look. All Champion radiators are backed by a limited lifetime warranty.

Flex-A-Lite
Aluminum Radiator, Dual-Electric Fan
Flex-A-Lite has expanded its line of direct-fit Flex-a-fit aluminum radiator and electric fan combinations for fullsize trucks to now include the ’04-07 Ford Super Duty F-250 and F-350 with the 6.0L PowerStroke turbodiesel engine. The system also includes a Flex-A-Lite exclusive clutch fan emulator that plugs into the existing control system, sending feedback to the truck ECM and avoiding potential check engine codes.

The radiator increases coolant capacity in the core by 16 percent, and it is hand-welded to the side tanks to withstand additional engine pressure. The Flex-a-fit high-performance aluminum radiator is manufactured in the United Sates, featuring a two-row core, hand-welded to side tanks with patented “T” channels.
Flex-A-Lite
800.851.1510, www.flex-a-lite.com

The dual 15-inch electric fans move up to 6,800 cfm of airflow. The entire core surface of the radiator is covered with a sealed shroud design.

Derale Performance
Powerpacks
Derale Performance has integrated their high-performing shrouded Powerpacks with the ultimate fan controller. Using high-output waterproof/dustpoof electric fans incorporated into aluminum shrouds these Powerpacks can conquer even the most extreme conditions.
Derale Performance
323.266.3850, www.derale.com

With the integrated patented PWM Fan Controller that utilizes Pulse Width Modulation to constantly adjust electric fan speeds from 0-100 percent, maintaining the optimal engine operating temperature. With built-in soft start technology, Derale has effectively introduced OEM reliability and function to the aftermarket. Made in the United States.

Flex-A-Lite
Aluminum Radiator And Electric Combo
Flex-A-Lite introduces its Flex-a-fit aluminum radiator and electric fan combination as a direct-fit for ’99-12 fullsize GM trucks and SUVs (except with 8.1L or diesel engines).

The Flex-a-fit radiator has greater coolant capacity than the stock radiator, and it features two-row, all-aluminum core, hand-welded to side tanks with patented “T” channels to dissipate heat more efficiently. Radiator mounting brackets are included for direct bolt-in fit to the stock location, and the “T” channels provide secure attachment for these mounting brackets.
Flex-A-Lite
800.851.1510, www.flex-a-lite.com

This dual 15-inch electric fan moves up to 6,000 cfm of airflow a Flex-A-Lite Variable Speed Controller that start the fans at 60 percent power and increases fan speed as the temperature rises.

Oil Coolers

C&R Racing
External Heat Exchanger
C&R’s External Heat Exchangers offer the option to have the heat exchanger in the tank of the radiator. Oftentimes packaging doesn’t allow, so this design gives the ability to place for convenience of plumbing out of harm’s way. The addition of “plates in the stack” increases oil cooling capability.
C&R RACING
317.293.4100, www.crracing.com

CBR Performance
Mini Off-Road Oil Cooler Kit
CBR Performance Products has brought “Mini Coolers” to the market.These coolers can fit in those tight, confined spaces and are constructed of aircraft-grade aluminum. They feature a unique internal turbulized fin design that improves the flow of oil more efficiently and benefits from its low pressure drop design configuration and maximum heat transfer.
CBR Peformance
951.245.2900, www.cbr-performance.com

This cooler comes with custom billet tanks and integrated shroud, with two, 4-inch SPAL fans for maximum airflow and cooling performance. The coolers can be used for universal cooling applications such as differential, power steering, and small engine cooling applications.

CBR Performance
Xl Off Road Oil Cooler Kit
CBR Performance Products specializes in manufacturing custom, high-performance, all-aluminum oil coolers. These coolers are constructed of aircraft-grade aluminum and feature a unique internal turbulized fin design that improves the flow of oil more efficiently and benefits from its low pressure drop design configuration and maximum heat transfer.
CBR Performance 951.245.2900, www.cbr-performance.com

This cooler has a custom integrated shroud and two, 12-inch SPAL fans for maximum airflow and cooling performance. These coolers are compatible with all engine oil and transmission fluid applications. All coolers are rated up to 150 psi and go through a vigorous testing cycle before they are released.

Flex-A-Lite
Cooler Cover Guards for Transmission and Engine Oil Coolers
Flex-A-Lite Cover Guards are formed and punched from 1/8-inch aluminum. They securely mount on Translife oil coolers using Flex-A-Lite Gator Clips. The design allows airflow, but protects the cooler from debris that could potentially damage it.
Flex-A-Lite
800.851.1510, www.flex-a-lite.com

Translife oil coolers from Flex-A-Lite have long been trusted to protect automatic transmissions, power steering and other vital components from damage caused by oil overheating, and now Flex-A-Lite has developed a line of cover plates to protect these oil coolers from rocks and other debris.

Derale Performance
Hyper-Cool Dual Cool Remote Cooler
Derale offers this compact yet powerful Hyper-Cool Dual Cool Remote Cooler. Perfect for engine, transmission, fuel, differential, or power steering needs, it utilizes an efficient 19-row Stacked Plate Cooler with two 5-inch waterproof/dustproof electric fans attached by an aluminum mounting bracket/shroud combination. Includes two -8AN male fittings and ½-inch barb fittings.
Derale Performance
323.266.3850, www.derale.com

Derale Performance
Scoop Cooler
Derale Performance’s Scoop Cooler is another industry exclusive, using Ram Air technology to force-feed air to their highly efficient 10-Row Stack Plate Cooler. Featuring a unique mounting bracket that sandwiches the cooler and the intake scoop, there are a wide variety of mounting options, all of which are designed to provide a clean, attractive, and highly efficient cooler. Derale’s Scoop Cooler is a heavy-duty cooler in every sense of the word, with integrated turbulators running through each row. It can be used for a wide variety of cooling needs from engine and transmission to power steering and fuel.
Derale Performance
323.266.3850, www.derale.com

Its all-aluminum design is lightweight while the furnace-brazed construction is tested to withstand pressures up to 300 psi, and guaranteed to 250 psi. The cooler is equipped with 7/8-inch x 14 (-10 AN) inlet/outlets; -6AN, -8AN, and -10AN fittings are available.

Electric Fans

Flex-A-Lite
Dual-Electric Fan System for ‘04-07 Ford Super Duty with Powerstroke
Made for their new aluminum radiator for the ’04-07 Ford Power Stroke, this fan shroud features dual Flex-A-Lite 15-inch electric fans that move up to 6,800 feet per minute (cfm) of airflow. That’s the highest airflow of any Flex-A-Lite electric fan system.
Flex-A-Lite
800.851.1510, www.flex-a-lite.com

The system also includes a Flex-A-Lite exclusive clutch fan emulator that plugs into the existing control system, sending feedback to the truck ECM and avoiding potential check engine codes. The electric fans are operated by a Flex-A-Lite Variable Speed Controller that starts the fans at 60 percent power and increases fan speed as the temperature rises and lets you adjust the temperature at which the fans turn on (between approximately 160 and 240 degrees Fahrenheit). The controller also includes terminals to activate the fans when the vehicle air conditioning is turned on, as well as cockpit manual override control for tow mode or water crossings.

Maradyne
Mach Two Extreme Electric Cooling Fan
Maradyne’s Mach Two Extreme Dual 16-inch fan provides increased cooling and better fuel efficiency for both early and late-model gas-powered trucks and SUVs with 33- to 34-inch wide radiator cores.
Maradyne
800.403.7953, www.maradyneHP.com

For increased off-road durability, the heavy-duty, 225-watt units features sealed motors that are IP68-certified dust-proof and waterproof.

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