Picking the right clutch for your Corvette can be confusing. Do you buy the one with the biggest price tag? The highest performance level? While it might seem logical at first, this kind of thinking is liable to leave you with a clutch that doesn't suit your driving style, or one that won't hold the power your car is producing. What follows is a guide to help you choose the correct clutch and pressure plate for your application.
Most clutch companies offer a variety of clutch materials and pressure plates, as well as twin-disc setups. Each type is designed for a specific use and has its own set of pros and cons. So, how do you determine which one is right for you? First, we'll need to brush up on basic clutch tech.
The clutch is, in simple terms, the link that mates the engine to transmission. When engaged (no pressure on the pedal), the clutch allows torque to be transferred through the drivetrain. When the pedal is depressed, it disengages the engine from the transmission, stopping the torque transfer.
Let's take a look at the components that make the clutch system work, beginning with the pressure plate. The pressure plate applies clamping force to the clutch disc, causing it to be squeezed between the plate and the flywheel. This effect occurs when you release the pedal. When you depress the pedal, the pressure plate releases its grip on the disc, and the torque from the engine is no longer transmitted to the transmission.
The pressure plate contains a couple of very important parts. When it comes to holding power, the diaphragm springs are critical. Simply put, the more diaphragm pressure there is, the more clamping force the plate will have. The biggest downside is that higher spring pressures typically require more muscle to depress the clutch pedal. Other drawbacks to a lot of diaphragm pressure include more stress and higher loads on the linkage and thrust bearings.
The second area of importance for clamping force involves the fulcrum points. By changing the fulcrum points, the laws of leverage may be used to create more clamping force. Although this approach doesn't result in the adverse effects that changing the diaphragm pressure does, it does have its own drawbacks. A mushy-feeling clutch pedal, longer pedal travel, and quicker disc wear can all occur.
Now that we've learned some pressure-plate basics, let's talk about the clutch disc. The disc is located between the pressure plate and the flywheel, so you can think of it as the salami between the two slices of bread. The purpose of the disc is to allow a smoother transfer of power from the engine to transmission.
Most discs are made with a sprung hub, which is designed to absorb some of the rotational force when the clutch is first engaged. Almost all street-oriented performance discs have sprung hubs, though some manufacturers do offer solid-hub discs. A solid hub is stronger but sacrifices driveability.
The Marcel is the thin slice of material between the clutch facing and the hub. It's designed to act like a cushion, giving a small amount of dampening when the clutch is first engaged. Again, it's all about driveability.
The last and-and, when it comes to performance, the most important-part of the disc is the clutch facing. The type of facing material used has a tremendous effect on the overall torque capacity of the clutch system. We'll discuss some of these materials and their respective benefits in a just a moment.
The flywheel serves as one of the two mating areas for the clutch disc, the other being the pressure plate. It also provides a place to mount the pressure plate and, in most applications, the starter ring gear. When replacing the clutch, you'll need to have the flywheel resurfaced or replaced as well. This will prevent premature wear and ensure optimum clutch-to-flywheel grip.