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Ford Mustang Fidanza's Twin Disc Clutch Set
MM&FF Explores The Latest In High-Performance Clutch Technology With Fidanza's Twin-Disc Clutch Kit.
The clutch assembly that converts engine power to a useful source of propulsion has been around about as long as the internal combustion engine itself. Over the years we have seen technological developments both in the design and the materials used that have made the clutch assembly better in every way.
In addition to advancements in clutch technology, great strides in engine performance have been made as well, but all too often harnessing great amounts of horsepower and torque have come at the cost of driveability in a number of areas, including the clutch and transmission. These days performance enthusiasts demand more and expect their dreams and visions to become reality. Thankfully when it comes to harnessing massive amounts of street power with the lightest touch, Fidanza has the solution.
Fidanza got its start when owner Lou Fidanza built and raced a Jaguar during the '79-'80 SCCA C-Production race seasons. The racing program proved to be a successful venture, and Team Fidanza used technical knowledge gathered from many winning race seasons to answer an increasing demand from other racers for access to Fidanza-like parts, and thus Fidanza was born. These lessons learned on track have become the basis for the design and creation of his company's high-quality parts and accessories. Fidanza now supplies the aftermarket with a wide selection of flywheels, clutches, cam gears, flexplates, short-throw shifters, and CV shafts. It also now produces a twin-disc clutch system for a variety of Mustangs.
Derived from racing applications where more clamping power was needed in a confined space, the multi-plate clutch system was born, and most systems have the added benefit of reduced rotating mass due to their somewhat smaller size, at least when compared to your typical single-plate clutch system.
"Older 7.25- and 5.5-inch twins that we used in our Jaguar racing program were like on/off switches, but you had to use them if you were making a lot of horsepower," says Fidanza Vice President Bob Scheid. "Either that or you had to use a monstrous pressure plate and single disc for clamping force." Obviously these characteristics don't lend themselves well to street-based applications, so the Fidanza crew went to work to produce a streetable twin-disc system that is easy to install, affordable, and has great driveability.
"Our twin-disc for the Mustang features an 8.75-inch pressure plate," notes Scheid. "We wanted to keep a stock-like pedal pressure, and actually ended up with less pressure than stock when compared with the '05-up GT pressure plate. We also strap the center floater plate (between the two discs), which causes the discs to engage incrementally. The pressure plate engages a split second before the disc on the flywheel side. It's really like driving a stock car, yet its designed to hold up to 625 lb-ft of torque at the wheels. The strapping on the floater plate also eliminates the annoying rattling that older twin-disc setups are known for. All this holding power does not mean that driveability is lost though. Pedal feel is virtually unchanged and engagement is as smooth as our 3.2 Kevlar single-disc unit."
Fidanza purposely engineered its twin-disc setup to be easy to install. "We made the stack height from the back of crank to the fingers of the pressure plate exactly the same as stock," says Scheid. "The only difference is an extra disc. This design also allows the use of the stock slave cylinder and/or clutch cable. We needed to offer a complete package as well, so customers get a pressure plate, flywheel, floater cage and discs, and everything is balanced, index marked, and ready to install."
Fidanza's twin-disc system starts with a 1045 high-carbon-steel friction surface mounted to an aluminum flywheel, and it's attached with nuts and bolts so the friction surface can be easily replaced. The pressure plate features a diaphragm design, and Fidanza offers the twin-disc system with several different types of discs to suit your vehicle's needs.
We recently installed Fidanza's twin-disc in a suitably high-horsepower Mustang that was in need of both a strong clutch to handle its 600-plus rwhp, as well as a more driveable clutch that would make the Mustang, once again, fun to drive. Said vehicle, belonging to Matt Guida of Land O' Lakes, Florida, is a '92 model that sports a healthy 383ci Windsor engine boosted by a Vortech T-trim supercharger. Guida recently picked up a T-56 six-speed transmission to replace a notchy five-speed box, and all that was required to fit the clutch to the transmission was a change in the spline count of the clutch discs.