Racing Performance Radiators with C&R Racing

Distilled or tap water in aluminum radiators? Which water wetter to use?

By Jean Genibrel


Racing, performance, towing and off-roading

   The cooling system is often underestimated by many race teams, owners, and especially privateers when they build or modify a racing car or engine. A team upgrading to a motor with more power or after adding more serious parts to the engine such as a bigger cam, or moving to higher compression would be best advised to build up their cooling system.

When it comes to selecting a radiator for your application, there are several factors to consider. The right radiator can make a significant difference in the performance and efficiency of your system. In this blog post, we will explore the key considerations to keep in mind when choosing a radiator.

1. What is the heat dissipation requirement?

The first step in selecting a radiator is to determine the heat dissipation requirement of your application. This is very difficult for  alayman 

So if you race a 500 horsepower small block motor in circle track, your radiator requirements will be different from those who run a 250 HP four-cylinder-car in road racing.

2. What is the size and space constraints?

Consider the available space for the automotive radiator in your application. Measure the dimensions and ensure that the radiator you choose fits within the allocated space. Additionally, take into account any size restrictions that may impact the airflow at the radiator.

3. What is the ambient temperature?

The ambient temperature of the environment in which the radiator will operate is an important factor to consider. If the ambient temperature is high, you may need a radiator with a higher cooling capacity to compensate for the increased heat load. In such a case you might consider adding an electric fan to the radiator to cool at lower speeds.

4. What is the airflow?

The airflow around the radiator plays a crucial role in its performance. Consider the airflow direction and velocity in your application. If the airflow is restricted, you may need a radiator with a higher fin density or a more powerful fan to ensure efficient heat dissipation.

5. What is the material and construction?

The material and construction of the radiator can impact its durability and performance. Aluminum radiators are lightweight and offer good heat transfer, while copper radiators provide excellent thermal conductivity but at an added weight. Additionally, consider the design and construction quality to ensure long-term reliability.

6. What is your budget?

Finally, consider your budget when choosing a radiator. While it's important to invest in a high-quality radiator that meets your requirements, it's also essential to find a balance between performance and cost. Compare different options and choose the one that offers the best value for your money. If you race the engine avoid cutting corners. An inadequate cooling system can cost a race and an engine!

By considering these factors, you can make an informed decision when choosing the right radiator for your application. Remember to consult with a radiator expert or supplier to ensure that you select the most suitable radiator for your specific needs. A well-chosen radiator will not only enhance the performance of your system but also contribute to its longevity and reliability. APPLIEDSPEED.COM offers the right balance in cost and efficiency for its radiators and oil coolers.

Drag increases as the frontal area of a radiator increases. Lift is also affected. Of course the higher the speed the greater this effect. This is why Stock Car teams tape the grill area for qualifying and when the weather cools down.


 Rock Crawlers, Jeepsters, and Dune Warriors can identify with large wheels and tires, driving in lower gears, high caster and scrub radius settings contribute greatly to creating heat. Adding towing and recovery equipment in front of small grill openings like on this Jeep do not help either. 

Radiator tube dimentions

Tube dimensions can vary greatly depending on application and manufacturer preference. The thickness of the tubes will dictate the dimension left for the fins.





 C&R is a supplier for INDY Car, NASCAR, and Formula1 among many other world class associations. The same radiators are available to the racing and performance public through APPLIEDSPEED.COM.

Other situations that warrant over-building the cooling system are in anticipation that the car or truck will be used in hot weather or run lower gears, race or drive on a muddy or icy surface or race course. These conditions will increase the engine RPM, power, and the amount of time spent in the RPM range associated with the increase in heat. 

Power is heat is power... However, advanced timing and lean air/fuel mixtures create more heat than a correctly timed engine at stoichiometric point (jetted correctly at 14 parts of air to 1 part of fuel by weight) while reducing power output. The cooling system uses up to 30% of the power the engine produces. Heat is (not always) power.

Late Model Modified C&R radiator

Late Model Modified is one of the most popular classes in circle track racing. These LMM purpose-built radiators come with a universal inlet design and a double pass system. C&R manufactures radiators and fan assemblies for road and drag racing, circle track, off road and performance cars. For off road, Jeeps, SCCA, NASA, NHRA. IHRA, NASCAR, and all other associations.

C&R pressurized cooling system

C&R produces a pressurized cooling system for racing cars and trucks. These units have allowed some teams to run their engine temperatures as high as 290 degrees without any troubles. The kit comes with a pressure relief valve that teams can set to any pressure. Formula 1 and Indy Car teams have utilized this cooling system for several years. 

 C&R Racing produces a pressurized cooling system that allows the temperature to run as high as 260 degrees.

Dirt Stock Car Racing is an example of where the cooling system could be over-built because of the real possibility of mud and dirt blocking the air intake. Off road racing cars, Jeeps and trucks cooling systems also qualify to be overbuilt.

Dirt car with mud in grillIn some forms of racing like in dirt oval track, mud and debris are an issue. Here again, over-building the cooling system favors the planners. It is easier to bring engine temperatures up than to bring them down. Off-roaders should also heed this advice.


So, if heat is power, why remove some of it? Too much of a good thing is not a good thing. Failure to maintain an engine at an acceptable temperature range will create damage such as burnt valves, blown head gaskets, cracked heads or blocks. Should an excessive amount of heat be removed from the engine, the power will drop accordingly.

Heat is power! So why remove some of it? Engines create an excessive amount of heat that we must remove to avoid engine damage. Radiators are the heat sinks used to maintain the engine temperature within an acceptable range. The purpose for a radiator is to dissipate a portion of the heat the coolant has picked up from the engine via convection. The coolant picks up the excess heat from the engine via convection, and it carries it to the radiator where the radiator tubes transfer the heat (calories) to the fins that are wedged between the rows of tubes, again through convection. From there, air, as it flows through the core, absorbs the heat stored in the fins and dissipates a portion of it to the ambient atmosphere


 In this video, C&R Racing explains how their extruded tube OE fit radiator modules with Spal fans add up to the ultimate for your ride for added cooling and strength.

Radiator thickness affects cooling depending on the air flow.

Thicker radiators cool better if they have enough air flow. Between a thick and thin radiator with low to moderate but equal air flow, the thinner radiator will very likely perform better. So if you have a street/drag car you may be well off with a radiator on the thinner side and if you road race or circle track your car opt towards a thicker radiator. A high fin count can make a cooling setup loud if the air flow is high enough.

Modern manufacturing techniques have improved quality of race radiators

The better race radiator manufacturers employ all the modern technology to produce a durable, effective and cost efficient product. Lean Manufacturing improves speed and reduces waste. Toyota Motor Company has pioneered Lean Manufacturing, and it has become the standard for many industries. Six Sigma Quality techniques originated in the aerospace industry and are used to prevent defects further. Each process is tested scientifically for possible failures and failures are prevented rather than being repaired. Manufacturers like C&R Racing use Computer Aided Drafting and Computerized Numerical Control to achieve tolerances of .005" to be maintained providing complete repeatability and reliability. 

C&R Sprint Car Radiator

 Furnace brazed cores ensure peak performance for years and eliminates the need for epoxy. Moreover, aggressive fin counts for all applications assure maximum cooling. Aggressive fin counts are more expensive and are therefore not used widely in the industry, but Griffin Radiator Company’s  racing experience has determined that it maximizes cooling capacity for the hard to cool applications.



Radiators (coolers) offer the advantage of taking the heat to the air. With air-cooled engines, we must transport the air to the heat. A disadvantage Porsche had overcome with clever ducting until engine power (heat) began to compete with aerodynamics and loss of power from trying to pump air. More can be said about the wicked aerodynamic consequences of managing a medium that we cannot see or feel, and at very high velocity becomes the density of molasses.

Never mount radiators or coolers without rubber support to absorb vibrations and chassis twist. Solid mounted radiators will crack in short order.


Aluminum is a wonderful metal but its weakness is that its low density makes it prone to cracks and breaks when placed under repeated vibrations. A radiator full of water, its hoses, brackets and possibly a fan can add up to a considerable amount of weight hanging on the mounts. As such, it is imperative that radiators never be mounted solidly in the chassis.


Radiator mounting

Radiators should be installed in such a way to allow easy and quick removal of the cap and to make filling with the coolant a clean and easy task.




Rubber mountsRemember that soft mounting applies in all forms of racing.  Damping sandwich mounts are available from These mounts screw into mounts and flanges to create a vibration proof environment for coolers and radiators. The mounts must be installed in support with the studs, vertical, not in shear.


The best way is to mount radiators is on soft material like rubber, foam, grommets, or other material that will isolate the radiator or cooler from the chassis vibrations and flex. In off-road racing or Circle Track Dirt, the environment is so abusive that a solidly mounted radiator will only survive a few minutes on a rough course. In road racing, circle track and drag racing the rule still applies.


.     With some radiators and coolers, you can fabricate a cradle lined with thick foam rubber to support the lower tank. The upper cradle can be made in a similar fashion, and it can just clamp on top of the radiator. Note: Allow the radiator to remain loose in the foam rubber to avoid stressing the core


Side tank radiators require brackets or studs to be mounted properly. The brackets will also need to be mounted on some soft material. Studs can be mounted on rubber isolators.

Image shows upper bracket with a stud. Rubber grommets are affixed over the stud, and the grommet slips into a hole inserted into a mount.

What Type of Water Should I Use in my Aluminum Racing Radiator?

Is Distilled Water the Best for Racing Radiators?

What about “water wetters”?


Some believe that using the wrong type of water without the proper additive can facilitate electrolysis where the ion depletion of the aluminum can create holes and leaks. While in some instances there is some truth to this claim, the reality is that using perfectly pure water (distilled, etc.) at the temperatures race cars operate, would cause minute, if any, damage. (“Guidelines for Use of Aluminum with Food and Chemicals”). Pure water (from distillation, deionization or by reverse osmosis) is free of solutes and salts. These solutes balance the PH in the water, and they offer a buffer to prevent the water from craving ions from the aluminum.



Some racers have the luxury to carry spare radiators and water. The cooling system in rally and off-road racing must be as reliable as those in a stock car or Sprint Car. There, the judicious choice of the type of water and its additives is paramount as it is in all forms of racing. Heed the “be prepared” advice when you go out in your Jeep or just sightseeing in the desert.

Tap water is the most readily available. The problem with tap water is that it is always unknown what types of minerals and in what quantities are contained in it. Well-water falls in the tap water category. Tap water can be utilized in race radiators if they have the proper additive installed. Tap water will leave residuals behind if the water is often drained or if it boils out of the system. Otherwise, the volume of solids contained in tap water is minimal.

Water, when heated, drives off a significant proportion of dissolved oxygen, but it reabsorbs fresh oxygen as it cools. This cycle leads to a perpetual cycle of corrosion, which is accentuated in cooling systems with no expansion tank.

Water also acts as an electrolyte if dissolved solids, such as hardness salts (lime scale), etc., are present. Salts promote galvanic corrosion where metals of high nobility sacrifice themselves to metals of lower nobility – this is often manifested by pitting. To avoid electrolysis, the radiator must be isolated from the rest of the vehicle and the electrical components, like electric fans and rotating components like transmissions, should be grounded to the frame, not the radiator. More reasons to mount radiators and coolers on rubber isolators.

 Distilled water is the purest form of water available. Distilled water is fully devoid of any minerals and other impurities. Distilled water is produced by boiling water and recapturing the steam. When the steam is cooled, it returns to water in its purest form.

The water in a radiator attacks steel, copper, and aluminum. Using distilled water and antifreeze is always the best approach to preventing corrosion. We can use tap water if we combine it with the proper amount of antifreeze, and, or, the correct water wetter. The type of water used is immaterial if it is mixed with the right additive. Photo courtesy Evans Cooling.


Evans Cooling Systems, Inc produces an engine coolant that Evans Chemists say never needs replacing and requires absolutely no water. In fact, ECS emphasizes that any water added in conjunction with their coolant will void their warranty as the water can produce steam pockets that can cause serious problems. The product is composed of a patented blend of ethylene glycol and propylene glycol with proprietary additives. Also, the coolants include other glycols to achieve their high boiling point and to eliminate the need for replacement.


Evans produces coolants for high performance, powersports and heavy duty, each product using a slightly different formulation to meet the environment. Jeeps, Fords, Chevrolets, Chryslers, Hondas, Toyotas, BMWs, and all other makes owners can find Evans Cooling Products at


Distilled water is a good choice for used aluminum radiators. If you install a new aluminum radiator just to check for leaks and you run distilled water through it, before the radiator is stored it must be dried thoroughly inside and out. Otherwise, run the motor for several minutes, or run a race before removing the radiator. This will prevent passivation and the possible leaks this process can cause. See the subject of "passivation" in this blog.



We must emphasize that some “wetters” do not contain the chemicals necessary to use with distilled water. The requirement with some products to use a tap water is due to the utilization of a corrosion package that doesn’t provide sufficient protection against the more reactive distilled water. Antifreeze is always safe to use with tap or distilled water if you race on dirt or your association allows it. Antifreeze contains all the anticorrosive agents to protect aluminum and iron, but not all the “wetters” contain all the additives for tap and distilled waters.

For racing, if no antifreeze is allowed, or if one chooses not to run antifreeze, tap or distilled water he may use Red Line’s Water Wetter. Water Wetter contains all the chemicals needed to bring distilled water to the right PH and equalize the ion craving effect of the water. Royal Purple’s, “Purple Ice,” and Lucas’ “wetter” are formulated for use in tap water only, as the products rely on some of the chemicals in the tap water to balance out the PH. C&R recommends its additive for use with distilled water only.  Amsoil’s “Dominator Coolant Boost” is not to be used with distilled water unless mixed with 50% antifreeze.

Red Line Water Wetter

Red Line’s Water Wetter contains all the minerals needed to neutralize distilled water, and it can also be used with tap, or distilled water. To avoid confusion just use tap or distilled water with the right quantity of Red Line Water Wetter.











 Always rely on the radiator manufacturer’s recommendations before filling the radiator with water, antifreeze or any additives like water wetters. Manufacturers may use different aluminum alloys that may have a different reaction to one water over a variant.

When using straight water with a new radiator never fill it and then drain it before having run the motor for several minutes. Letting a new radiator sit when still wet will cause the ion migration to eat small holes in the aluminum, turning the radiator into a garden sprinkler. Allowing the radiator to “cure” by leaving the hot water in the radiator, or running the car for a race, will cause the aluminum to form a thin barrier of oxide. This process is known as “passivation.” Once passivation has taken place any clean water we can use any water in the aluminum radiator.






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