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Radiator Tech Tips From C&R

C&R Racing's Chris Paulson presents at the AETC conference.

C&R Racing’s Chris Paulson presents at the AETC conference.

C&R Racing is one of the most trusted manufacturers of radiators and cooling systems in racing. In fact, C&R owns nearly 100 percent of the radiator market in NASCAR.

More important to us, they are also very big in dirt track racing, especially with Sprint Cars. C&R major domo Chris Paulson recently led a discussion at the Advanced Engineering Technology Conference (AETC) held every year before the PRI racing trade show and laid out some great information when it comes to keeping your race car cool. We thought we’d pass along a few of his tips to you here.

 

Fluid Choice

Many dirt tracks aren’t as strict about only using water in the cooling system as they are at asphalt tracks where anti-freeze spilled on the racing surface can make it slick as ice. But Paulson points out that there is nothing currently available that works better at pulling heat out of the engine and transferring it to the aluminum in the radiator than good old fashioned water. He did say that there is some magic fluid that the US Navy runs in it’s nuclear submarines that has better heat transfer properties that simple water, but it’s top secret and probably toxic so we racers aren’t going to be able to get our hands on it any time soon.

This also includes coolant additives that advertise a “40-degree drop” in water temperatures. Paulson says he’s tested all of the additives and none do anything when it comes to improved cooling versus straight-up water. However, he does recommend avoiding tap water if possible, instead using distilled water.

Radiator Cooling 02

Radiator Corrosion

The reason you want to avoid straight tap water if possible is because a modern aluminum radiator is quite susceptible to corrosion from the minerals and other “stuff” found in our drinking water. The minerals will separate from the water and adhere to the aluminum surfaces. Not only will this corrode the thin-walled tubing, but it will also reduce the radiator’s ability to pull heat from the water and exhaust it into the atmosphere. This is also the result of the rusty crud you almost always find in the water passages of an iron engine block.

The easy answer is to use only pure water which has been distilled. Some bottled waters have been distilled, but not all, so you have to check the label. Of course, we live in the real world, and a gallon of distilled bottled water can cost more than a gallon of gas. Tap water is practically free and available anywhere there is a spigot, so we know racers aren’t going to stop using it. This is where the water additives are actually useful. They don’t reduce water temps as many advertise, but many from the more reputable manufacturers (Driven Racing Oil, and Red Line are two such) do include chemicals that “lock” the aluminum so that the minerals found in water won’t combine with it.

Radiator Cooling

Passivation

“Passivation” is a cool term for aluminum radiators referring to a chemical process that causes the aluminum to become less susceptible to corrosion. In practice, it’s a lot like heat cycling helps stabilize an engine block. Paulson says passivation occurs naturally over a few heat cycles and forms a natural protective layer on the microscopic level on the walls of the radiator’s aluminum tubes that will help prevent corrosion.

When a new aluminum radiator is first produced, it is fully annealed. It is dead soft, nearly pure aluminum–so  you can imagine that it is susceptible to contaminants. So you have to be very careful to protect the radiator until passivation has had a chance to take place. Paulson mentioned a NASCAR Cup team he worked with that purchased several new radiators during the off-season. In an effort to get ahead on the to-do list before the racing season started, a crew member pressure tested each radiator using tap water. When the radiator passed, he drained out most of the water–but didn’t dry out the radiator–and put it on the shelf. When racing season drew close and the radiators began to be installed on the race cars, all had corrosion on the inside walls of the tubes and several were already leaking. Of course, the race team tried to blame the radiator manufacturer, but they quickly realized it was from allowing moisture to sit in the brand new radiators. So make sure you fire up the engine and run it up to temperature at least once after installing a new radiator.

 

 


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