Clutch 101: Getting a Grip on Performance Clutches

Price

Buying the most expensive clutch that you can afford is rarely the right choice. A high-quality, single-disc clutch system may be sufficient for many light-to-medium tuned cars, while high-torque-capacity, multi-plate systems may be best for purpose-built racecars.

The best practice is to determine what your application requires then include the cost of that clutch system into your overall budget. The last thing you want to do is go through the trouble of building your engine and subsequently negate the increased power output by installing a clutch kit that’s insufficient for your needs. Additionally, you don’t want to spend extra money for torque-holding capacities that your clutch may never see.

Safety First

Many race-sanctioning bodies require certain parts to be certified to minimum safety standards. The SFI Foundation is one organization that tests and certifies clutches and many other performance parts for use in racing or other official competitions. Check with your sanctioning body to see if SFI certifications are required for your competition class or level and ensure that your clutch meets these requirements.

The Right Clutch

To choose the right clutch for your application the first time, make sure you take all the preceding factors into account. In addition, knowing your application’s peak torque output, The overall weight of the car, and the types of performance driving you plan to do will help the manufacturer assist you in choosing the right clutch system. In many cases, the best clutch for your application will be the one whose torque capacity is slightly above the engine’s output.

CLUTCH TROUBLESHOOTING CHART

PROBLEM
Clutch can’t hold the torque

SOLUTIONS
• Increase pressure plate clamping force and/or
• Use a higher coefficient of friction clutch disc material and/or
• Move from a single disc to twin-disc or twin-disc to triple-disc system


PROBLEM
Clutch has very harsh engagement or is hard to modulate
SOLUTIONS
• Increase the clutch disc surface area (i.e., change from 4-pad to 6-pad disc or from 6-pad to full-face disc
• Try a less aggressive friction material in the disc


PROBLEM
Transmission cannot perform quick enough gear changes after installation of performance clutch
SOLUTIONS
• Switch to a lighter-weight clutch disc.
• Consider a smaller-diameter multi-plate system


PROBLEM
Clutch wears out prematurely
SOLUTIONS
• Clutch may be slightly slipping and causing friction material to wear prematurely: see solutions for a clutch that can’t hold torque
***Note your driving style to see if you’re riding the clutch. This occurs when your foot remains on the clutch pedal between engagements. Your foot should only be on the pedal when engaging or disengaging the clutch.