Getting Shafted
Carbon Fiber Shafts Put More Power To The Ground
By Michael Ferrara
Turbo & Hi-Tech Performance - October 1996

When it comes to going fast, many concentrate on producing more power at the engine. Unfortunately, any experienced racer can tell you it is not the power at the crankshaft which propels the vehicle. In actuality, it is the percentage of this crankshaft power which makes it to the ground that is the true measure of performance.

The Physics: In efforts to improve the efficiency, racers have experimented with everything from ultra-light flywheels to lightweight, low inertia wheel-and-tire combinations. In general, their attempts have improved a vehicle’s ability to accelerate and put power to the ground. In some applications, the side effects of an ultra-light flywheel negate the benefits. For example, drag-racing vehicles depend on a near-stock-weight or heavier flywheel to store the necessary amount of energy for an explosive launch. Since the launch is the most critical aspect of a drag race, most racers can’t afford to give up launch quality by using a lightened flywheel to pick up a slight improvement in acceleration. Of course, other forms of racing, which are less dependent on acceleration from a dead stop, can benefit from the use of lightweight flywheel setups. In contrast to lightweight flywheels, a lightweight wheel-and-tire combination has no real drawbacks as long as enough wheel strength is maintained.

The History: In the past few years, a number of competitors in different types of racing have been setting new records thanks, in part, to one local company. Advanced Composite Produces and Technology, Inc. (ACPT) of Huntington Beach, California. This company has been designing and manufacturing carbon-fiber composite driveshafts for over 10 years. In 1987, ACPT produced a carbon-fiber driveshaft for Dan Gurney’s ISMA GTO car which was experiencing a serious problem. The metal driveshaft would develop a harmonic whip which limited the engine speed. ACPT came to the rescue and manufactured a carbon-fiber driveshaft that eliminated the problem. Without a driveshaft rev-limiter, the Gurney team was able to bring engine speeds up to redline which helped them take home the season championship. Over the years, carbon-fiber shafts have been tested in drag racing as well as multiple forms of road racing.

Carbon-Fiber Composites: Carbon or graphite fibers are the reinforcement of choice in the majority of high-strength, high-modulus (stiffness) resin-matrix composites. The material properties of carbon-fiber composites make them an attractive alternative to metal components in a variety of applications. Case in point, the carbon-fiber driveshafts manufactured by ACPT offer improved in-vehicle performance while weighing less than half of a metal shaft.

The ACPT carbon-fiber driveshafts offer three advantages over metal shafts. First, the shafts are substantially light in weight and in turn also have a much lower inertia. Our testing of a supercharged LT1 Camaro on a DynoJet chassis dynamometer showed a power gain at the wheels that increased as the engine made more power. At 3000 rpm, the shaft put nine additional horsepower to the ground. At 5000 rpm, when the engine was making almost twice the power, this number nearly doubled. Second, the carbon-fiber shafts dampened vibrations two to 10 times faster than a metal shaft. The ability to quickly dampen vibrations translates into reduced rearend and tire shake at the other end during a hard launch or brisk acceleration. In addition, transmission and rearend parts do not experience the additional wear caused by vibration. Third, the carbon-fiber shaft increases driver safety. The one weakness of the carbon-fiber driveshaft (resistance to high energy impact) turns out to be a valuable asset in terms of safety. Every ACPT carbon-fiber shaft is designed specifically for the horsepower, torque and critical speed it will encounter when put into service. Even in extreme use, the shafts have proven they will not fail. If the shafts were to fail, the danger to the driver and car is greatly reduced. Instead of maintaining a rigid structure that can whip around and damage the driver, the shaft turns into what looks like a broom. According to Dick Anderson of Dick Anderson Racing. “Last season, a bracket came loose, destroying the torque arm and broke the ACPT shaft in two, but it never came in the car. It ‘broomed’ just as ACPT said it would, and no one was hurt.”

Recently, ACPT designed and built a carbon-fiber shaft for our Project Talon. Our first round or testing indicates no problems and we’re preparing for a trip to the strip to do a before and after evaluation. Our current plans include outfitting the Science Project Mustang and the Project Seven Camaro with carbon-fiber shafts starting at $550, carbon-fibers are not going to be in everyone’s budget, but if you need to stay ahead of the competition it’s a small price to pay.

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Contact Information:
Email us at: info@acpt.com
Call us toll free at: (800) 799-7893
or Call us at (714) 895-5544
International +01-714-895-5544
Fax us at (714) 895-7766

Advanced Composite Products and Technology, Inc.
15602 Chemical Lane
Huntington Beach, CA 92649 - USA

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