Inside ACT Clutches
There are a lot of choices out there for clutches, whether you’re looking for something as simple as a stock replacement or as complicated as a twin-disc race clutch. Friction materials, hub design, spline count, release pressure, and much more – it’s enough to make your head spin. Add in the fact that some suppliers source their clutch components from all over the world, and you have to be an expert to get it right on the first try. Unless, of course, you take advantage of those who are already experts, like Advanced Clutch Technology. With more than 15 years experience designing and building all kinds of high performance clutches right here in the United States, ACT has what it takes to help you find the right clutch for your application, and to make sure you’re getting power to the ground once it’s installed.
We recently took a tour of their facilities in Lancaster, California, where they make their trademark bright yellow clutches, as well as high performance pressure plates and flywheels. They gave us an inside look at the manufacturing process, as well as the extensive quality control checks they employ to make sure you’re getting the best clutch they can provide.
Clutch covers, powder-coated ACT yellow, await assembly with diaphragms and pressure plates.
ACT clutches are well known in many different forms of racing for their strength and durability. They are perhaps best known for their products in Formula Drift, though, a motorsport that puts a tremendous amount of stress on a car’s clutch. By “kicking” the clutch pedal at high RPM to break the back wheels loose, drifters slide their cars sideways on the edge of control. Smoking tires are expected, but a smoking clutch is a disaster, and instantly applying 500 or more turbocharged horsepower is a brutal test of any clutch.
One factor that separates ACT from many other clutch manufacturers is that ACT makes or machines all of their parts in house. This gives them complete control over their products from start to finish, allowing better-than-OEM levels of quality. They make clutches for just about every brand, import and domestic, and many of their parts are SFI-spec, meaning they are approved for extreme duty in drag racing.
These ductile iron clutch face castings are much stronger and more durable than their OEM counterparts – an important factor when spinning to 7500 RPM or beyond, just inches from the driver’s toes.
A good example are the ductile iron face castings used for their pressure plates. The ‘gray iron’ typically used in factory clutches is weak and brittle compared to ductile iron, and with some ACT clutches rated to withstand 400% more torque than an OEM clutch, it’s easy to see why they’d use the better material. A pressure plate coming apart under stress can ruin your whole day (as well as totaling your car and activating your health care plan) and ACT understands that there’s no way to cut corners on critical components.
Because the work is done in-house, it’s much easier for ACT to quickly produce clutches for new applications or do custom designs.
ACT doesn’t just make their own parts – they design them as well. A good example is their patented diaphragm spring. This critical component not only determines how much clamping pressure is applied to the clutch pack, a key factor in the torque capacity of the clutch; it also has the biggest influence on pedal feel and how much strength it takes to disengage the clutch between gears. It takes careful engineering to balance these competing design criteria, and by handling it all in-house, ACT can produce clutches with tremendous holding power and reasonable pedal forces. Taking it one step further, ACT also does the heat-treating of this component themselves, ensuring that the diaphragm springs have the proper flexibility and strength they need thousands of miles down the road as well as when you first install the clutch kit.
Though some components, like these clutch cover stampings, come in partly finished from other suppliers, all the final machining and assembly work happens in ACT’s Lancaster, California facility, ensuring that every clutch kit that goes out the door is up to the same high standards.
One all the individual parts have been machined, heat treated, powder coated, or heat-treated, they need to be assembled. Assembling the pressure plate is an involved process, made all the more complicated due to ACT’s rigorous quality controls and testing procedures. Each pressure plate is dynamically balanced before meeting up with the clutch disc, which goes through a similar process to ensure the assembly spins without vibration once installed.
A multi-puck clutch disk gets its friction materials riveted to the hub.
ACT’s racing history dates back to the import drag racing scene that flourished in the late Nineties. In response to the turbo fours showing up at the track with far more power than any stock clutch could endure, ACT President and founder Dirk Starksen began producing racing clutches for this niche market, which quickly expanded to include street applications, then domestic RWD cars as well. Today it’s hard to find a vehicle or form of motorsports that isn’t covered in ACT’s extensive product line.
ACT believes in “win on Sunday, sell on Monday” and has a long history of backing successful cars, like Brent Rau’s 7-second Mitsubishi from the heyday of import drag racing.
Starksen thinks of the racetrack as a test bed for his products, as racers will throw everything they can at the clutch until it blows, giving ACT a chance to go back and make an even better product. Almost everybody at ACT is a performance enthusiast or weekend racer, and it shows in the vast amount of knowledge applied in every part of the company, from design to production to customer service.
ACT Founder and President Dirk Starksen knows that racing is the best test of his products.
ACT has found their products being used all over the world in just about every form of four-wheeled sports. What started with import drag racing has branched off into drifting, domestic drag racing, time attack, rally, and even land speed racing at the Bonneville Salt Flats. ACT’s dedication to the racing world doesn’t just make better race cars though. This technology trickles down to the clutches they make for the street as well, especially as cars get ever more powerful straight from the factory. Replacing a clutch is something you don’t want to do any more often than you absolutely have to, and ACT is determined to make sure that you do it with the right parts the first time.