(This article first appeared in the November 2008 issue of SportsCar magazine)

By Philip Royle

You’ve just finished your mid-summer, 30-minute Club race, and you peel yourself out of your racing seat and douse yourself with water in the hopes of cooling off. Your face is red, you’re dripping sweat and you’re lucky to be standing. The worst part is that when you look around, there’s someone that appears full of energy and is ready for another race – if only that were you.

There are tricks to having your body deal with the stresses of a race (i.e.: exercise), but the fact is you’re going to wrap a multi-layer Nomex suit around you, strap yourself into a racecar designed for maximum aerodynamics rather than  ventilation and place yourself in a pretty high-stress situation for an extended period of time. No matter what shape you’re in, when temperatures rise to over 100 degrees in the car, your body is going to react – and that can lead to sweating, a lack of concentration, judgment and reaction errors and possibly even disorientation.

This problem is nothing new. NASA’s space program was dealing with the same issues with the Apollo program in the 1960s. NASA’s solution came in the form of a complete body cooling system, routing liquid filled tubes around the astronauts. If this technology can get us to the moon, surely it must work in a racecar.

The solution

In 1987, Rich Shafer noticed that surgeons needed a way to keep cool during long operations, and that led him to NASA’s space research from nearly 30 years prior. All of this ultimately resulted in the formation of Shafer Enterprises and the invention of the Cool Shirt.

The Cool Shirt consists of a T-shirt with 45 feet of medical grade capillary tubing stitched to the shirt, and that is connected to a water filled cooler; a motor in the cooler then pumps cold water through the shirt, cooling the wearer. Being a racer and a long-time SCCA member, Shafer realized the Cool Shirt’s potential in a racecar, and brackets were made so the system could be strapped into virtually any production-based racecar.

“Once it’s 95 degrees or higher, you get no evaporative cooling at all,” explains Cool Shirt’s John LaDue. “As your body temperature rises, your hypothalamus gland tells your body to send blood to your skin for cooling, [but] if you’re in a 150 degree car, you’re basically not getting rid of any of your body heat.”

According to LaDue, it’s normal for the blood to be sent to the skin for cooling. Usually, the body sends about 4 percent of the blood to be cooled; under extreme conditions, up to 48 percent of your blood can go to the skin.

“When that happens, the blood is being pumped away from vital organs like your heart, your liver and your kidneys. When that much blood is gone from your core, you start to get dizzy and nauseous.”

Another side effect is your decision making process slows, increasing the potential for  mistakes behind the wheel.

“The Cool Shirt holds about 10oz of water and the flow rate is about 24oz of 45 degree water over a period of about one minute,” explains LaDue, noting that water has the ability to cool the body 28 times faster than air. “Covering 40 percent of the body, the cooling effect of the water going through the tubing will cool one cycle of your blood.”

There are several similar setups to the Cool Shirt available from a number of companies, and you can find a few homemade how-tos online. However, we prefer using something tried and true because there are few things more distracting during a race than having ice-cold water dumped in your lap.

Installation and use

The Cool Shirt package that will work for most SCCA Club racers in production-based or GT racecars is the Club 12 system. For $289, you get a 12-quart cooler with a water pump and eight feet of insulated dry disconnect hoses. You’ll also need to order a shirt (Cool Shirt offers Carbon X and Nomex shirts), and if you so choose, you can order the mounting kit, although it’s easy enough to fabricate a bracket.

“You want to make sure to bolt the mounting tray to a section of the frame, not just the floor pan in case you have any kind of high g-force crash situation,” notes LaDue.

The electric pump within the cooler is simple to power. A 12v power source and a ground is all you need, although you’ll probably want to connect this to a switch the driver can operate from within the car.

“Some drivers can actually get too cold with the shirt, so it’s nice to have the flow control on it,” says LaDue, referring to the company’s temperature control switch that slows the flow of water to the driver. “You could also turn the machine off. Most drivers will put in some kind of toggle on/off switch. The disadvantage to that is you get a little bit of a cold shock when it starts up again.”

The 12-quart system will supply enough cooling for around three hours. Cool Shirt also offers a 24 quart system that is good for an estimated six hours.

With the cooler mounted, the motor wired and the insulated tubes threaded to the driver, the only thing left is connecting it to the shirt, which is worn beneath the driver’s racing suit. For that, there are several options.

“You can take the shirt tubes through the suit pocket, you could get a seamstress to make a hole in the side, or a lot of guys simply run it out through the zipper,” says LaDue.

Maintaining the system

“You can drain the cooler using an extra fitting on the cooler, towel it out and let it sit,” says LaDue. “As far as the shirt goes, if you’re using it on a fairly regular basis, we have a maintenance additive, which is an anti-fungal product that we recommend you add to the unit every time, which stops growth from forming in the line.”

Should anything clog the lines, the water flow will slow and the connectors could get plugged. If you’re storing your system for more than 30 days, it is recommended you drain the water completely, which involves blowing air through all the tubes.

Similar to your race suit, the Cool Shirt T-shirt should be washed. “You can put the shirt in a washing machine on the gentle cycle and then put it in the drier,” says LaDue. “It is pre-shrunk cotton with very easy maintenance. You’ll get several hundred washes out of it before you have to do anything to it.”

A driver cooling systems like this could very much be considered a safety item. When your body’s core temperate exceeds certain temperatures, you no longer are operating at your best, and at racetrack speeds, that can be dangerous. The human body was never designed to do some of the tasks we ask of it (sitting in a 130 degree cockpit for 30 minutes while battling for on-track position comes to mind), thus minimizing the impact to the body is a good idea. Be it a home-brew cooling concoction or this pre-packaged Cool Shirt setup, if you race when it’s hot – and who doesn’t – this is one item you’ll never be sorry you installed.

Cool Shirt, http://www.coolshirt.net