How do you get the driest car ever? Do you use more chemical? Change chemical? Move the dryers closer to the last liquid arch or closer? The ultimate answer may be a story of less is more. Everyone knows that a drying agent is the key to drying a car in a tunnel or an automatic car wash. By following these tips, an operator can obtain a vehicle that is “drier” by the end of the drying process.

Step 1: Of course, you need to start with a product designed properly to dry a car and not just bead the surface. All drying agents function differently, and the cost and performance of these varies tremendously within a company’s line and amongst competitors. My advice to an operator is to shop with a reputable national provider who has experience in hundreds of tunnels. Once you identify a leading company, work within their product range to identify a product that leads to the best results for your operation.

Step 2: Make sure that your chemical level is optimized- which might mean turning it down! Why would you want to use less chemical? If a drying agent isn’t working well, wouldn’t it make more sense to turn it up? Within some limits, the reality is that sometimes using more chemical leads to a less dry car. Most service representatives are not aware of this trick of the trade and will turn up the chemical more and more trying to achieve a drier car. This can leave you with higher costs and a wetter car. For example, the graph below illustrates how reducing the amount of drying agent can actually improve drying. For this example, we used Cool Dry, a popular drying agent. Note that a ratio of water to chemical of 400:1 leads to the fastest drying time unit of 4.9 seconds- a 30% reduction vs. using a 200:1 ratio. In this case, the 4.9 seconds measures the amount of time it took for gravity to drop 90% of the water off of a vertical surface. The results? Half as much leads to a 30% improvement in drying. A reputable carwash detergent company should be able to look at the gallons of water used to find the ideal ratio and then verify the ratio through field experimentation.

To get the driest car ever, follow one or both of the above steps. Use the right chemical from the right company (a reputable company with a well-designed and researched product) and then use the optimized amount of that chemical. Find a great supplier/distributor who will work hard, be creative and leave you with results that are exceptional. A great supplier may not have the lowest price- but they may have the lowest cost approach with the best results!

Brent McCurdy is Managing Director of Blendco Systems. Blendco manufactures a full line of detergents and waxes for the professional carwash industry. For more information about and examples of the drying agents mentioned in this article and other Blendco products, visit