Transfering power with driveshafts

Upgrading a driveshaft with a lighter, stronger and more balanced piece.

Custom Bay driveshaft Dynotech Engineering Services Dynotech specialty parts vehicle accessories The driveshaft is one of those unsung heroes of vehicle upgrades. Not readily visible, it often falls under the category of, "If it ain't broke, don't fix it." On the other hand, when one of your customers plans on upgrading a vehicle with a high-performance engine and later-model transmission, why mate them to an old, heavy steel driveshaft?

You don't need a degree in engineering to understand that it takes more energy to move a heavier item than a lighter one. So it stands to reason that a lighter driveshaft requires less torque to turn it along with the wheels. Even so, simply installing a lighter driveshaft is not the only consideration for you.

For details on the finer points of engineering, we sought out some pointers from Dynotech Engineering Services, a company with more than 80 years of experience with rotating assemblies. This firm started out as a contract balancing service business that supported its current parent company Balance Engineering. Dynotech and Balance Engineering were founded by General Motors in 1923 and are based in Troy, Mich.

To minimize noise, vibration, harshess (NVH) Dynotech Engineering Services balanced anything that was attached to a vehicle: rotors, pulleys, crankshafts and driveshafts. In addition to working with the Big Three OEMs, Dynotech later helped NASCAR teams looking to solve their NVH problems.

Today, Dynotech Engineering Services produces products for professional racers and high-performance enthusiasts alike. This means your customers can have the same driveshaft technology used by their favorite NASCAR drivers for as low as $329 (for a steel driveshaft), and in as little as a couple of business days.

Dyotech Engineering Services offers driveshafts in a variety of other materials, such as 6061 T6 aluminum, DOM steel, chrome moly and carbon fiber. These units are suitable for street, restoration and racing applications. Each driveshaft is checked for and straightened at three points in the build process. Once this has been completed, components of the driveshaft are balanced prior to final assembly.

After the driveshaft is assembled, it is balanced again at speeds up to 9,000 rpm. According to Dynotech Engineering Services, the main advantage of balancing the driveshaft at high speed is that you get a much more precise and cleaner imbalance measurement that indicates vibration issues. Whenever there is vibration in the driveline, power is lost that could be delivered to the wheels and converted into acceleration.

After a Dynotech 6061 T6 aluminum driveshaft was fitted on the 1974 AMC Javelin shown here, the most noticeable thing was the significant reduction in weight from the stock piece. Another obvious improvement is in the aesthetics. This driveshaft looks so good that you almost don't want to hide it up underneath the car. No unsung hero on this ride!

Steve Temple is a freelance technical writer and photographer with more than 25 years' experience. He has served as director of sales and marketing for Shelby American and as online editor for major magazines such as Hot Rod, Car Craft and Rod & Custom.

Driving Customer Upgrades

THE PART Custom driveshaft

THE DISTRIBUTOR Dynotech Engineering Services 1731 Throncroft Troy, MI 48084-5302 800-633-5559 www.dynotechengineering.com

THE CHALLENGE: Provide a stronger, lighter and more balanced driveshaft than what came with the original vehicle, along with custom lengths for modified powertrains.

TIME TO COMPLETE Usually in as little as 15 minutes, using measuring tape (for custom orders) and box-end wrenches.

COST TO YOU To be a dealer, there is usually a minimum initial order of five driveshafts, or a $3,000 buy-in. But smaller shops might be able to achieve dealer status and jobber pricing over time, with three orders in six months.

Once a shop has reached dealer status, it can maintain that by selling $5,000 worth of product per year.

PROFIT POTENTIAL Volume discounts are available for bulk orders, with the amount of margin determined on a case-by-case basis. On average, a dealer can expect to make 17 to 20 percent on the resale of a driveshaft, plus installation and equipment charges.

No single product seems to sell better than others, as many are built to order for custom projects. However, the 2005 and newer Mustangs are popular in many of today's markets, and several dealers stock one-piece driveshafts that replace the factory two-piece units.