Case Study: Shelby Series 1 Car Needed a Better Clutch

The Shelby Series 1 is a seriously high-performance roadster, designed by Carroll Shelby and made by Shelby American. In the late 1990s, a fellow engineer needed the help of Phoenix Friction Products to get a clutch in the car that could handle the power.

The Problem with the Clutch Already In Use

The car had a clutch from a competitor of Phoenix Friction Products that was - unfortunately for our competitor and for Shelby - a major source of problems. Here’s what was noticed when trying to track test the Shelby Series 1 using the original clutch system:

1. They couldn’t get the car around the test track without the clutch blowing out, at least not if the lap was aggressive
2. There were shifting problems due to distorting and flexing in the pressure plate, leading to a very poor driving experience
3. Shelby wanted to use the same exact clutch for the stock 320hp Series 1 and the 550hp supercharged version, mostly to reduce costs and complexity. The goal was to handle this amount of horsepower with a 9 inch single plate clutch setup.

Due to our reputation for solving difficult clutch problems, Phoenix Friction was given the opportunity to identify and correct the issues with Series 1 clutch.

Addressing Premature Clutch Failure and Shifting Issues

The issues outlined above were due to the fact that - simply stated - the overall design of the clutch was very poor. The supplier Shelby originally used simply didn't understand the challenge the Series 1 presented.

Our solution:

• Using our bench and lab testing equipment, engineering resources, and many years of experience with clutches, we were able to identify the flaws in the design — most of them were rooted in poor quality and a design that was allowing the pressure plate to distort and flex.
• After testing carbonic buttons and high heat heavy duty ceramic buttons, we were able to come up with a design and friction material that was able to grab and hold adequately, even in the 550 horsepower version of the Shelby Series 1
• We worked with Shelby to integrate our clutch design into the existing vehicle to minimize the impact of our clutch design on manufacturing

We're proud to say that our design solved the clutch problems the Series 1 was having, allowing Shelby to begin promoting the car to the press and making deliveries to customers.

We often talk about our experience working the Series 1 to demonstrate our unique skills and experience. Many, many clutch companies offer products that are adequate for small engines and basic applications, but it's a very short list of companies that can produce a quality clutch for any application, even something as specialized as a limited production supercar.

Additionally, we talk about the Shelby experience because the process we used to design, develop, and test the clutch kit for the Series 1 is the same process we follow for all vehicles. It's our combination of skills, expertise, and a great development process that allows us to produce world-class clutch systems and components.