Over the past few years, Project Y2K has seen a steady flow of performance upgrades that have elevated it from a garden-variety C5 Corvette into the realm of formidable modern sports cars. At the drag strip, Project Y2K was a mid-to-high 13 second car when we made our initial passes with it, but these days it’s capable of dipping into the high 11s. You don’t make those kinds of performance gains without a significant dose of both power and grip.
Project Y2K has seen a mixture of daily driving and track use over the years. This ’00 C5 Corvette makes roughly 470 horsepower at the wheels on spray these days, which is enough to get this 3,200-pound car into the high 11s. After a recent thrashing, the clutch started showing signs of distress and we knew it was only a matter of time until it gave up the ghost, so we turned to Fidanza Performance for a replacement clutch and flywheel.
It’s no secret that hard launches can put a lot of stress on a transmission, and when it comes to manual gearboxes, that’s most often translated into clutch wear. We knew that sooner or later the additional output and mechanical grip was going to send that assembly to the boneyard, and after a recent beating, we started hearing sounds emanating from the gearbox that indicated the current clutch wasn’t long for this world.
Rather than wait for the transmission to leave us stranded on the side of the road, we decided to nip the issue in the bud by procurring a replacement piece from Fidanza Performance. The V1 series clutches are designed to provide OEM-level drivability in street cars while bolstering durability in vehicles making more power than stock.
Fidanza Performance’s V1 series clutches are rated at up to 660 lb-ft of torque, which makes this perfect for Project Y2K. Folks with builds above and beyond the V1 can step up to the V2 series clutches, which are rated at up to 850 lb-ft of torque. Like the V1, the V2 discs also have sprung hubs and come with premium ceramic friction materials for vehicles with higher torque levels.
In this feature we’ll take a closer look at the features of the V1 clutch with some insight from the experts at Fidanza Performance and go through the key points of the clutch installation in Project Y2K.
While factory-installed clutches are typically tuned for every day drivability and can last a long time if you’re gentle with the gearbox, the story changes significantly once you start adding power and really put the car through its paces at the track. Also, since these are wear items, it’s worth considering the fact that automakers have to weigh the cost versus return when it comes to selecting parts like these for mass produced vehicles, which means you’re probably not getting the best part available, but one that meets the OEM’s established standard and can be produced in large quantities easily. The upshot is that there’s often plenty of room for improvement by turning to the aftermarket for a clutch replacement.
All of Fidanza's clutch castings are CNC-machined for increased precision and consistent build quality, and the V1 clutch disc uses a friction material with high copper content to bolster its heat tolerance, thus helping prevent clutch fade. The splines of Fidanza clutch discs are also broached to a tighter tolerance than their OEM counterparts, improving fitment with the input shaft, which in turn extends the life of the spline.
“Our clutches are all balanced within .25 oz, many OEM clutches are only balanced to .50oz,” explains Matt Polena of Fidanza. “Also, you can see between 10 to 60 percent increase in clamp load over OEM depending on the application, and even with an increase in clamp load, the V1 clutch will still maintain a stock to moderate increase in pedal feel, which makes it a great upgrade for any daily driver that has some extra horsepower.” Polena also points out that, for those competing with their vehicles, the factory clutch might not be enough to meet the rules of the sanctioning body. “Most Fidanza replacement discs meet SFI Specification 1.1 and are legal for use in racing organizations where SFI certification is required,” he explains.
When it comes to components like these for high performance applications, aftermarket companies that hone in on a specific forte often find ways to innovate and improve upon the established status quo. In terms of clutch design, this can mean not only better performance, but extended longevity as well.
SFI 1.1 certification is required to compete in some classes under specific sanctioning bodies, and many of Fidanza’s flywheels and clutches carry this certification. However, Fidanza also aptly points out that just because a part does not have an SFI number does not mean it is not a quality part – it just means it has not been tested by SFI. This testing process can be costly and time consuming for the manufacturer, so which parts are SFI certified and which are not often simply comes do to the expected likelihood that a specific part would be popular in racing applications. It does not serve as an indication of a quality difference between one part and another.
The splines on our clutch discs are broached to a tighter tolerance than OEM. The tighter tolerance helps increase fitment to the transmission input shaft, increase the life of the spline and improve clutch release. -Matt Polena, Fidanza Performance
“Fidanza started by making the highest quality flywheels in the industry, and our clutches carry with them the same quality,” Polena tells us. “All of the clutch castings are CNC-machined for increased precision and consistency. The clutch disc with the V1 clutch is made with premium organic friction material with high copper content which bolster its ability to manage heat and avoid fade. Also, the splines on our clutch discs are broached to a tighter tolerance than OEM. The tighter tolerance helps increase fitment to the transmission input shaft, increase the life of the spline and improve clutch release.”
Rated at up 660 pound-feet of torque, the V1 clutch for the ’97-’04 C5 Corvette (PN 698571) is designed to handle significantly more grunt than the 350 lb-ft of torque that the car’s LS1 was generating in stock form. “The key to handling more power is stronger materials,” says Polena. “We offer a stronger diaphragm, drive straps, and top grade rivets. These are all used when needed to help strengthen the pressure plate and discs to prevent breakage and help handle significantly more power. We also heat-treat the diaphragms and the contact bearing release area is hardened to help reduce wear.”
In the past, improved clutch horsepower tolerance versus stock often came at a cost – not just in terms of expense but in clutch effort and feel as well – resulting in less commute-friendly drivability. In the case of the V1 clutch Fidanza’s engineers took these concerns into account during the design phase, but at the end of the day, a lot of it also comes down to simply picking the right part for the application. “A big part of drivability is the friction material and selecting the correct clutch for your driving style,” Polena explains.
Many of Fidanza's clutches are developed to OEM dimensions to ensure a proper fit with the OEM flywheel. Keeping the OEM dimensions also helps to avoid any clearance and fitment issues.
“Fidanza does not offer harsher disc materials like sintered iron, we keep things simple by offering two types of disc materials. Our V1 clutches offer a full faced organic disc. This disc is sprung hub and a step above your OEM disc, offering quicker shifting, increased strength and heat tolerance. If a driver has issues with drivability, the problem typically stems from running the incorrect clutch, as many drivers ‘over buy’ clutches. We see people purchase clutches that can handle a 1,000 ft-lbs of torque, but their vehicle only produces 500 ft-lbs of torque, and this leads to drivability issues.”
The Qwik-Rev Option
If a driver has issues with drivability, the problem typically stems from running the incorrect clutch, as many drivers “over buy” clutches. We see people purchase clutches that can handle a 1,000 ft-lbs of torque, but their vehicle only produces 500 ft-lbs of torque – this leads to drivability issues. -Matt Polena, Fidanza Performance
Fidanza also offers enthusiasts a way to make their clutch replacement process easier and potentially cheaper with their Qwik-Rev kits. These offer a complete clutch upgrade package by pairing up a matched set of components for the job, which includes a Fidanza aluminum flywheel, a V1 or V2 series clutch disc, an uprated pressure plate, and all the ancillary pieces you’ll need.
“One of the key advantages of purchasing a Fidanza Qwik-Rev kit is the cost savings,” says Polena. “You can save a couple bucks by purchasing the clutch and flywheel together as opposed to buying the parts separately.”
But beyond cost savings, the Qwik-Rev kits provide additional piece of mind that the new parts are going to function with factory-like refinement. “The Qwik-Rev kits also come balanced as one unit to help reduce any possible noise or vibrations,” says Polena. “If purchased separately, it would be up to the customer to have the flywheel and clutch balanced together, so it’s a great option if you are worried about increased noise with a new flywheel. Also, anytime you move to a lightweight flywheel you’ll hear warnings about ‘lightweight flywheel noise’ or more correctly called ‘gear rattle.’ Our Qwik-Rev kits are set up with a sprung hub clutch disc which helps to dampen and absorb the rattle.”
The lightweight flywheel and matched parts also benefit performance in general, so they’re a common choice for vehicles that regularly see use in motorsport as well. “We see a lot of different applications that benefit from our Qwik-Rev Series – everything from autocross, road racing to even drag racing,” Polena says.
Despite the performance advantages of switching to a lightweight flywheel, some builders opt to stay with the stock flywheel due to concerns about noise. Fidanza’s Qwik-Rev kit addresses those concerns by offering a match set of components for a complete clutch replacement. These kits are set up with a sprung hub clutch disc which helps to dampen and absorb that gear rattle.
Replaceable Flywheel Friction Surfaces
Many flywheels are able to be resurfaced, however resurfacing can lead to engagement height issues, slipping and trouble getting into gear. Fidanza’s replaceable friction surface eliminates that issue. The replaceable friction surface is a feature that is incorporated into all Fidanza flywheels and easily replaced when needed.
When the time comes, drivers can purchase the replaceable friction surface for a fraction of the cost of a new flywheel. Fidanza’s replacement kits come with military grade aerospace fasteners featuring mechanical, self-locking nuts with built-in washes for reliability and strength. The friction plate itself is constructed of high quality 1050 steel and are pickled and oiled to deliver superior longevity and disc engagement.
“Those who autocross and road race see a lot of benefits entering and exiting corners. The lightweight aluminum flywheel that comes with the kit helps drivers to dive deeper into corners and stay off the brakes longer. On the opposite side, exiting a corner drivers are able to get back into the higher RPM range quicker to exit the corner faster.”
After getting Project Y2K back to the shop, we got the installation of the Fidanza V1 clutch underway by first putting the car up on a lift and removing the exhaust system so we could get to the torque tube that’s entombed in the transmission tunnel under a protective shield.
Once the torque tube was exposed, we noticed that the long-tube headers we’re using would likely have to be moved out of the way to get the clutch out.
Much of the job is simply a matter of getting to the clutch assembly. The first order of business to get to the torque tube, which involves removing the exhaust and the 34 bolts that hold on the torque tube cover. Our long-tube headers were also in the way, so they needed to be unbolted from the motor to provide room to get the clutch out. Lastly, the rear suspension and transaxle cradle needs to be unbolted to provide clearance to disengage the torque tube from the clutch so the old one can be removed and the new on installed.
Once the headers were unbolted out of the way we were ready to turn our attention to the rear suspension and transaxle cradle, which needed to be unbolted so the torque tube could be moved back, allowing us to remove the old clutch in turn. This involves unbolting the upper control arms, shocks, and all the electrical connections on the transaxle. The calipers are hung separately, and the transaxle is secured to a trans jack with tie downs to prevent it from making an unexpected exit.
The slave cylinder from the line that leads to the clutch master also needs to be released by depressing the white ring with two flat blade screw drivers, which should pop it free and allow it to separate.
While we were at it, we replaced our slave cylinder and throughout bearing. We also added a speed bleeder from Hinson Motorsports to the equation to allow us to bleed the clutch more easily when the time came. (Middle) Here you can see the replaceable friction surface, that means you won't have to buy a new flywheel ever again. (Right) The clutch is maneuvered into place while a technician holds back the torque tube and rear cradle assemblies.
Instead of removing the torque tube from the vehicle entirely, we left it more or less where it was and just moved it back so we could slide out the old clutch and remove the old flywheel. Since leaving the torque tube in place didn’t allow us enough space to get the clutch alignment tool in place, we just used the input shaft from the torque tube as our alignment tool - one tech pushed the torque tube into place while the other moved the clutch disc into place until everything aligned. After everything was in place, the clutch was torqued to Fidanza's specifications. After that it was more or less a reversal of the clutch removal process.
After moving back the torque tube and removing the old flywheel and clutch, the new parts could start to be installed, beginning with the new flywheel. We decided to reuse the existing pilot bushing since it was fairly new and in good shape. After maneuvering the new pressure plate and clutch disc into place and aligning everything, it was simply a matter of fastening everything down to spec and reinstalling the parts that had been removed to access the clutch assembly.
After torquing the pressure plate down, reinstalling the torque tube cover, bolting up the headers, and securing the rear suspension cradle back into place, the car was essentially buttoned up again. The last step was to bleed the clutch before taking it out for a road test to make sure everything was copacetic.
Has the clutch in your ride seen better days? Give the folks at Fidanza Performance a buzz and find out how you can improve your transmission’s performance while adding durability with their V1 and V2 series clutches, replaceable flywheel friction surfaces, and Qwik-Rev kits.