​Drivetrain Upgrades

Drivetrain Upgrades

Your Mustang's engine can be making more power than a top fuel dragster, but it won't do any good if you can't transfer that power to the transmission. By making the right upgrades to the clutch, flywheel and surrounding parts, you can get reliable launches while keeping drivability impact to a minimum.


How a Clutch Works

A clutch shares a lot of design similarities with a disc brake. The flywheel, which is connected to the crankshaft, has a flat metal surface, while the clutch disc is covered in friction material similar to what is found on brake pads. When the two meet, they should lock against each other. However, instead of halting the vehicle, the connection between the clutch and flywheel transfers power between the engine and the transmission.

The clutch is pushed against the flywheel by the pressure plate, which is pushed down by the diaphragm spring. The diaphragm spring uses fingers made of spring steel which meet up with the throwout bearing.

Stock vs. Performance Clutches

The stock design is made for easy driving and can't handle much more than the stock engine output. Racing clutches are built for extreme temperatures and massive torque loads, but are hard to engage and can chatter at low RPM. Street performance clutches strike a balance, providing plenty of room for increased power while still being easy to engage so they can be driven around town. Each component of the assembly is altered to get the right characteristics for clutch engagement and performance:

Making the diaphragm spring stronger, increasing clamping force. This helps keep the clutch from sliding against the flywheel, but it also increases clutch pedal effort.

Performance clutches use materials including brass and ceramic formulations that can withstand more heat and higher friction loads for harder launches and faster shifts encountered on the track.

The area of the clutch face will be smaller. By reducing the contact area, the clamping force can be concentrated into a smaller space, increasing the pressure between the clutch pads and flywheel. Some performance materials need high amounts of clamping force to be effective.

To see the difference, just look at the CCI Stage 1 and Stage 5 clutches: the street-focused Stage 1 uses a stock design with improved materials, while the Stage 5 has a sprung center to dissipate vibration and 6 small clutch faces for high pressure engagement.

Flywheels

The flywheel is both a drivetrain component and an engine component. The inertia of the flywheel stores energy from each ignition stroke to keep the crankshaft spinning long enough to get to the next ignition. Switching to a lighter flywheel reduces inertia for faster revving but makes the engine run rougher.

On the drivetrain side, it's the contact point with the clutch. Like a brake rotor, it needs a smooth, flat surface to get maximum contact with the clutch material. If you're reusing the flywheel when replacing the clutch, it needs to be machined.


How Many Splines Does the Clutch Need to Fit?

The clutch you use needs to be able to fit the splined input shaft of your Mustang's transmission. The number of splines on that shaft will depend on which transmission you're using:

The stock Tremec/Borg Warner T5, T45, TR-3650 and T56 use a 10-spline input shaft. That includes every 5-speed used in the Mustang as well as the 6-speed found in 2003 and 2004 Cobras. This shaft is a common point of failure on these transmissions, so most rebuilt or replacement units with any performance intentions are fitted with a 26 spline input shaft, including Ford Racing's own Tremec T5 Extra HD.

The Tremec TR-6060 used in the Shelby GT500s built from 2007 to 2014 use a 26 spline input shaft.

The Getrag MT82 6 speed used on 2011 and later Mustangs has a 23-spline input shaft.


Clutch Break In

To get the clutch properly broken in, the car needs to be driven about 500 miles in town. The constant stops and starts combined with the low power load causes the right temperature fluctuations to knock off any high spots on the clutch surface and embed clutch material into the flywheel. Installing a clutch in your car and immediately using it for launches can cause the clutch surface to glaze over, reducing friction and maximum torque capacity. If that happens, the only way to fix the problem is by installing a new clutch plate.


Get the Parts You Need to Put Down Power

Anderson Ford Motorsport doesn't just sell performance Mustang parts , we test them and use them to help our customers build cars that meet their performance goals, so we know what works. We offer everything you need to keep your engine and transmission connected whether you're doing some mild upgrades or building a drag monster.