Getting into gear: How to choose the right clutch for your Porsche.
Clutches are a wear item and at some point in their life, they'll need to be replaced. Whether you're looking to improve the performance of your vehicle or your clutch is simply just slipping and in need of replacement, you have several options. The OEM replacement clutch is a good baseline but you might also consider an aftermarket solution.
Upgrading your clutch with an aftermarket solution is just one of the many ways to enhance your driving experience in your manual transmission. More precise gear changes, better drivetrain engagement, and longer clutch life are just some of the benefits of upgrading. But before you go buying any Stage X clutch, you should understand the benefits and trade-offs of certain kits.
A clutch assembly is going to be very similar on all manual transmission cars, as they all operate the same way.
A flywheel is attached to the motor, and provides a thick, metal surface for the clutch to grip and slip onto. This flywheel is always turning with your motor, and comes as either a single-mass, or dual-mass setup.
- A single-mass is a just one solid flywheel, CNC'd from one piece of aluminum or steel.
- A dual-mass flywheel has two pieces, joined by a compression spring system that provides reduced engine harmonics (noise). Usually larger and thus heavier.
Your clutch disc has a surface similar to a brake pad, which works to grip the flywheel, and thus transfers the rotation of the motor to your transmission, all the way to the wheels.
Behind the clutch is the pressure plate. This controls when your clutch is pushed up against the flywheel, or with the push of a pedal, allows the clutch disc to spin freely and separately from the motor. The pressure plate uses a spring diaphragm to create this pressure.
The throwout bearing, pushed by the clutch fork is what disengages the pressure plate, and this is all controlled from the slave and master clutch cylinders on your car.
There are 2 ways to increase the "torque rating", or power at which the clutch is able to withstand reasonably before slipping. You can increase the pressure plate spring pressure, which results in a heavier clutch pedal, and well built calves to follow. Or, you create a clutch plate with a stronger friction material which will grip the flywheel better, but might create jittery 1st gear starts or squeaking when cold.
Now that we've discussed components of your clutch setup, let's talk about how to replace it.
OEM Clutch Replacement
Is your Porsche garage-kept, paint-corrected, and driven mainly to PCA meets or a weekend drive? This might be the right choice for you. OEM clutches last anywhere from 50k to 120k miles safely, very dependent on driver style. Softer driving will give you more life out of your clutch, but ultimately it won't last forever.
Sachs manufactures most of the OEM clutches and flywheels for Porsche, but you'll also find replacement OEM kits from Luk or others that provide a similar to factory fit and performance. If you're experiencing some slipping or your clutch isn't on the cush of catastrophic failure, than you can likely just replace the clutch and leave the flywheel alone.
Sprung vs Unsprung?
One thing you should pay attention to when buying a replacement clutch is going to be the presence of clutch springs, which make a big difference in engagement and clutch feel for the driver. Some Porsche OEM models like the 911 Carreras or Cayman/Boxsters came with unsprung, solid discs. Other models like the 911 Turbo or GT3 came with sprung clutches.
The clutch springs are located in the center of the clutch disc. Shown below is a comparison of the 997 Carrera vs Turbo OEM clutches (from Sachs). Since the Turbo has more power and torque, Porsche opted to use a sprung setup from the factory, something unnecessary in the more tame, naturally aspirated Carrera at the time.
A sprung clutch helps absorb small changes in momentum/vibration during gear changes, thus providing a smoother gear change especially at low RPM's. An unsprung clutch makes the transmission and shifting experience something to practice and conquer, as the more direct transfer of energy is felt in every shift. Most aftermarket clutch kits will come in sprung and unsprung versions, allowing the driver to choose which they'd prefer.
Determining which Stage clutch is right for you
Now if you're past replacing your clutch with the same old parts from Porsche, than you can decide on what clutch setup will be best for your driving application. A spirited-driving weekend car will have a different solution than a dedicated auto-cross machine.
Stage 1: OEM+ feel and operation. Slightly higher torque rating than your factory replacement. Great to for any application as these will provide a longer life with the same driving style, and you won't remember a difference in the pedal feel after the first drive.
Stage 2: Track season is coming up, and it's time to get rid of that beat clutch because you know it's going to slip in 3rd out of turn 6. This clutch level would be a great option for most track-minded cars that still have a plate on the rear, and a desired comfort when driving to and from the next event.
Stage 3 - 5: At this point, the importance of the pedal feels is likely heavily outweighed (pun intended) by the requirement of torque capacity on your clutch. Each level has a specific torque rating, and usually after stage 3 the pedal will feel the same. These clutches should really be made for track-purpose vehicles, and are usually paired with a lightweight aftermarket flywheel. Common symptoms of driving a Stage 3 and up clutch on the streets would be jittery first gear starts, squeaking from slow engagement, and a requirement for heel-toe.
Clutch Replacement Tips:
- During a clutch replacement we like to lightly scuff the flywheel and clean it to ensure a good surface for the new clutch to mate to.
- Always remember to break-in your clutch softly over the first 200-300 miles for best long term results. It's very important you avoid slipping which could result in heat spots during the break-in period. If replacing the flywheel and doing an aftermarket clutch, break-in period may be reduced.
- If your flywheel does have excessive scoring, or multiple discolored heat spots, you should probably consider replacing the flywheel.
- As with anything else, always follow the manufacturer's torque guidelines when reassembling your clutch and transmission!
To see our full lineup of clutches for your Porsche, check out our partners Spec Clutches, Clutch Masters, and Sachs. For special inquires or questions about upgrading your clutch system, contact us directly at firstname.lastname@example.org