It works like this – reduce the overall mass, and you have a lighter vehicle. A lighter vehicle requires less horsepower to achieve equivalent performance, which means a smaller, lighter drivetrain can be used, reducing mass further, which means you can carry less oil and coolant, reducing mass further, which means smaller braking components can be used, reducing mass further, which means you could fit smaller, lighter wheels and tires, hence reducing mass further, which adds up to better fuel mileage, so you can fit a smaller fuel tank, carry less fuel, thus reducing mass further and… You get the picture. That’s just the beginning – there are further benefits to the OE like reduced freight costs, handling costs, assembly costs, and the list goes on.
As performance enthusiasts, we’re all concerned with weight. When it comes to speed, common sense says that lighter is faster – and I’m here to tell you that this is indeed true.
Those of you who know me know that I’m a suspension guy (hopefully, Mike and Dave will vouch for me if I get called to the carpet on that), and, while reducing weight is good for the reasons mentioned above, suspension guys especially love reducing unsprung mass for the big gains in handling performance that it affords. If you’re new to the concept of sprung and unsprung mass, the chassis and all the components rigidly attached to it (things that are held up by the springs, hence the term “sprung”) such as the body, drivetrain, exhaust, interior, etc… are considered sprung weight. Unsprung weight is basically the moving bits that are hung on the car by the suspension and not directly connected to the chassis, like wheels, tires, calipers, and rotors. For calculation purposes, the stuff that’s in between – whatever creates the interface between the sprung weight and unsprung weight, like control arms, springs, struts, shocks, panhard rods, trailing arms, and so forth, is usually considered 50/50 – half of the mass is considered sprung and the other half unsprung.
Why does reducing unsprung weight improve handling? In simple terms, with all things being equal, the car that maintains the most consistently loaded tire contact patches is going to have the best handling. Less unsprung mass means the tire can react to changes in the road surface more quickly and maintain optimum traction.
All that being said, what’s all this talk about plastic? Enter composite materials – sometimes known as FRP, or Fiber Reinforced Plastics. Most people think of woven carbon fiber saturated in some kind of resin when they think of composites, but the definition is much broader than that. Composites are defined as materials that are made from two or more different materials that have very different chemical and/or physical properties. When combined, the different materials are still separate and distinct, but the new material has properties that are different from, and usually much better than, the individual components that make it up.
Most composites consist of a matrix or binder (like epoxy resin), and a reinforcement, such as carbon fiber or glass fiber. Fact: the most common composite in the world? Concrete, which is a combination of aggregates (basically gravel) – which serve as the reinforcement – and cement, which is the matrix that binds it all together. So, where are we going with all this? We’re going racing, of course!