Choosing a Clutch for Your Daily, Your Dedicated Racer, and Everything In Between

Shop Performance Clutches at Boostin Performance

If you notice your clutch is beginning to slip, whether it's getting worn out or it can't keep up with recent power upgrades you've made, it may be time to invest in a new one. A quick glance at aftermarket clutches can show a wide variety of clutches available to you, so we're here to clear the air and help you decide which is best for you and your vehicle.

Clutch Fundamentals: What It Does & How It Does It

Let's start by noting that we'll be talking about clutches in manual transmissions, those that sit between the engine's flywheel and transmission (where a torque converter would go on an automatic transmission). Simply put, a clutch is what allows you to shift gears in a manual transmission. A clutch is splined to the input shaft of your transmission and uses friction to engage the flywheel, transferring the engine's power to the transmission. Connecting the engine to the transmission is a pretty important part of getting your car rolling.

How to Know Your Clutch Is Slipping

A slipping clutch happens when your clutch applies inadequate friction to the flywheel to mate the surfaces, allowing the flywheel to spin faster than the clutch. You may only notice this from a dead stop, where your engine speed will increase disproportionately to your vehicle speed. You may also notice a burning smell under load if there is significant slippage.
Especially in the case of stock clutches, clutch chatter is a good indicator that it's time to replace some faulty components. Clutch chatter is when your clutch skips across the flywheel as it tries to engage, causing a very noticeable vibration/shudder that can be felt throughout your vehicle. This can happen as a result of both worn-out clutches and contaminated clutches. Clutch chatter can also occur with lightweight flywheels and harder clutch materials.

The Differences Between Clutch Materials

Organic Clutches

Pros: • Great for street driving • Comfortable • Low-cost

Cons: • Low heat resistance • Prone to glazing in high-heat

Kevlar Clutches

Pros: • Long lasting (2-3x organic life) • Moderate heat resistance • Delivers consistently smooth engagement • Good for slightly modified vehicles

Cons: • More prone to permanent damage if overheated • Long break-in period (1,000 miles) • Requires higher clamping pressure

Metallic/Cerametallic Clutches

Pros: • High-friction material: • High heat resistance: • Good for heavily modified vehicles

Cons: • Not particularly comfortable for street driving: • Can have rough engagement

Sintered Iron Clutches

Pros: • Extremely high horsepower compatibility • Extremely tolerant of heat • Friction increases with heat

Cons: • Engagement is virtually “on” or “off” • Only suitable for race applications • Requires special flywheel

Clutch Material Surface Area

A clutch's ability to hold under power is a simple function of friction. What determines any clutch's frictional capabilities is a combination of clutch material, surface area, and clamping force. These things require a delicate balance to give your car the exact driving dynamics you're looking for, so choosing the right clutch is an important decision.
Clutches come in two main variants, those being full-face and puck-style clutches. Full-face clutches line the entire outer edge of the clutch with clutch material and are what you'll find on just about every factory vehicle. Plenty of full-face clutches are great on the track too, depending on the spring rate and clutch material they employ.
Puck-style clutches use pucks of clutch material and are much more aggressive in terms of engagement, as they have a much higher amount of pressure per square inch on the mating surface. While they have less clutch material, the increase of pressure effectively increases the friction. Worth noting, the quick engagement of puck-style clutches sacrifices comfortability for shift speed.
Another way to increase clutch material surface area (and ultimately friction) is to use a multi-disc clutch setup. Instead of just one disc lined with clutch material being pressed against the flywheel, multi-disc clutches employ multiple discs lined with clutch material to spread the frictional force over more surface area. You'll typically only find these on high-horsepower applications.

Sprung Vs. Unsprung Clutches

You may notice that some clutches have integrated springs, and some don't. So what's the point of those? Sprung clutches integrate coil springs that act as a buffer between the spline drive and the outer clutch material, smoothing the transition between disengaged and engaged. Sprung clutches also help to even out drivetrain noise. So, the main benefits of sprung clutches are comfortability and driveability.
Yet, unsprung clutches surely have their place, right? They absolutely do. Since they offer instant engagement between the flywheel and the transmission, unsprung clutches are your best bet for drag and drift applications. They may not be as comfortable, but that comes with the benefit of performance.

Single Disc Vs. Multiple Disc Clutches

Just about every manual transmission vehicle will come from the factory with a single disc clutch. They're cost-effective, comfortable on the street, and they simply get the job done for most vehicles' everyday duties. With the multitude of clutch materials and styles available, single disc clutches find their way well into the field of racing as well.
However, there comes a point where sending all of an engine's torque to a single disc can overcome its frictional capabilities and spin the clutch instead of the tires. As we mentioned, a multi-disc clutch is a great way to increase friction for those high horsepower setups. Multi-disc clutches can hold much more torque than their single-disc counterparts, allowing you to lock up even when your throttle is pinned.

Find Your Aftermarket Clutch at Boostin Performance

If you're still unsure which clutch is best for you and your build, we at Boostin Performance would be happy to help. We supply aftermarket performance parts for DSM, EVO, GT-R, and Supra vehicles, along with the expertise to maximize your performance. See our inventory for your vehicle, then check out our installation services to see how we can get your car rolling. Boostin Performance has the right parts to bring your aspirations for your car to fruition, so inquire today.