Larry Dixon CR

When we first introduced Larry Dixon’s ’66 Nova build, to say we were anxious to eventually see the final product was an understatement. We’ve already shown you the rebuilding of the suspension, and ultimately, installing the Chevrolet Performance Supercharged LT4 crate engine. But, no matter how well an engine is put together or how great the parts are that are used for the build, if it overheats, it becomes a big lawn ornament. For that reason, Larry reached out to the crew at C&R Racing to help with his cooling needs.

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Although it looks completely different than the original radiator, this dual pass unit fits perfectly in Larry’s Nova. The two conections with the blue caps are for the engine coolant, while the red caps allow connection of an oil cooler. As of this writing, the radiator does not have a part number, but should be available soon.

C&R Racing has designed and built some of the most rigorous cooling components for many of the top teams in professional motorsports. We’re even told that for the past 25 years, every NASCAR Cup Champion, Indy 500 winner, and Daytona 500 winner have utilized C&R components on their car. That was good to know, as Larry’s car presented some serious hurdles that needed to be overcome. Oh, and did we mention that those hurdles needed to be overcome in just a couple of weeks?

Radiator fitment is the first concern when designing a cooling system for any car or truck.

For starters, When Larry installed the supercharged LT4 above the engine mounts in his Nova, as far as we know, he was the first one to do so. That means that no aftermarket parts had been developed to accomplish this task. That in turn means there were no radiator options available from an over-the-counter source.

When he told the guys at C&R Racing what he was doing, since they were close to his shop, they sent a few guys over to see how they could help. Larry told us, “They saw what we had, decided what we needed, and went back to their shop and built it. Two weeks later we had a radiator.” Larry continued, “Just by taking a few measurments, they were able to design a radiator that fit. What’s more, it works great.” According to Roger Rosebush, marketing guru for C&R, “When choosing the correct radiator, fitment is the first issue that must be overcome.

The key to successfully cooling a custom car such as this involves many variables. – Tulley Esterline

“If a radiator does not fit the application, it will not work at all. But even if the radiator does fit the application, you must also have proper air flow passing through the radiator for it to work.” We Asked Tulley Esterline of C&R, what is needed to be considered when designing a cooling system, and he said, “The key to successfully cooling a custom car such as this involves many variables. The key factors are good airflow, and utilizing the available packaging space in such a way that any incoming air through the grill will move sufficiently over the radiator’s core. Once a plan is in place, this strategy then drives the final size of the parts.” Tulley finished with,  “At this point, we can tailor the core’s fin count, fin height, core thickness, etc., to achieve maximum performance.”

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The reinforced extruded tube from C&R Racing gives their aluminum radiators a burst rating of 100 psi.

How Cool Do You Have To Be?

As Roger and Tulley eluded to, the amount of airflow through the radiator is a huge factor in how well it keeps an engine cool, but exposed radiator surface area is just as important. Why you ask? As air passes through a radiator, it becomes warmer. Therfore, the coolant flowing through the back row(s) of a radiator is trying to be cooled by air that has already passed over the front row of tubes and has been heated. Although the differential is minimal, it does reduce the cooling ability of the rearward tube(s). Maximizing the face area of a radiator exposes more coolant to the coolest air possible, therfore increasing the radiator’s heat transfering capability.

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We have all experienced a cooling issue at some point, and we asked Tulley about one that comes up quite often – What could cause overheating while driving at low speed or sitting at a red light, and he said, “The answer to this is almost always lack of airflow through the radiator, which is generally cured with the addition of cooling fans to help move air through the radiator when the free stream air is limited.” If you have ever driven through a parade or sat at a red light for too long and watched your temperature gauge climb, this is what Tulley is eluding to.

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When using a stock radiator in a stock aplication, a fan shroud is often necessary to get the air flow to travel through the radiator. By strategically placing two electric fans, there is adequate fin coverage to make sure that evey pass of the coolant is affected.

Many times, a good fan shroud can help alleviate that problem. This is because, if a shroud is not used, the fan can pull air from all areas around the radiator, which means less air is coming through the radiator to help cool the engine.

Radiator Basics

When it comes to choosing a radiator, there are two types of construction to consider – copper and brass, and aluminum. In a copper and brass-constructed radiator, the tanks and the fins are made of copper, and the coolant tubes are brass. While copper has excellent thermal-conductivity, brass is not as efficient.

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According to Roger, “Copper is an old-school technology that is going away. When assembling a copper and brass radiator, lead is used to join the two mediums. The problem with using lead is that it does not absorb heat and therefore cannot remove heat from the cooling system. A copper core radiator also uses multiple small tubes. The main downfall of using copper and brass is the cost. Conversely, an aluminum radiator is less expensive to build, and typically utilizes larger tubes that deliver more coolant flow.”

Cooling Capacity

A radiator’s cooling capacity is not as it sounds. We are not talking about how much coolant a radiator can hold, rather, capacity refers to the amount of heat the radiator can dissipate. The surface area of a radiator is very important when discussing heat dissipation capacity, but how does a person decide what capacity radiator they need?

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Proper coolant flow is paramount to a properly working cooling system.

According to Tulley, “In order to determine radiator capacity for a specific project, there are many aspects that need to be considered. The first thing to look at is the horsepower requirement of the engine. Knowing this helps to paint a picture of the task at hand. After that, we must consider the surroundings, including the available packaging space, grill opening/available airflow, water flow rate produced by the engine, and ambient conditions of the vehicle (air temp, operating environment, etc.).  Developing a sufficient cooling package requires looking at all the various aspects of a project, and then developing an appropriate solution based on the known variables.”

Extruding Maximum Cooling 

It is hard to argue that the advent of aluminum radiators has definitely given performance enthusiasts more options with their cooling needs. And like all things, improvements upon an already good thing are bound to happen. C&R Racing introduced their version of an improvement by delivering an all-new aluminum radiator that features an extruded tube and a reinforced race fin design. The reinforced race fin design is exclusive to C&R, and actually features a hemmed-forward-edge. According to Roger, “The fins on a typical radiator are very thin, and even the force of the wind can fold them over. When this happens, the fins can block air flow. By folding over the forward edge of the fin, it is stronger than a typical radiator fin.”

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C&R’s extruded cores have multiple passages in a single radiator tube. This not only adds strength, but eliminates the possibility of tube swelling as well.

The reinforced extruded tube has another quality that is unique to C&R Racing, it gives their aluminum radiators a burst rating of 100 psi. Since a typical radiator in a musclecar runs anywhere from 13 to 18 pounds of pressure, this virtually guarantees that no ballooning of the tubes will occur. Rosebush continued, “With a typical radiator, the tubes are up to 1-inch wide, and with the higher pressures that many engines are running, it’s possible that the tubes balloon/expand. As that happens, the air gap between each row of tubes becomes smaller, which restricts airflow.”

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So now that you have a basic understanding of how your cooling system functions, and why C&R Racing’s new extruded-core radiator is a great upgrade, it’s the perfect time to sit back, order yours, and make your hot rod cooler than it’s ever been.

Check back as our next installment highlights how Larry and his Nova tackled 1,000-plus miles of public roads and five drag races in five days.