Hundreds of new product announcements cross the desks of PRI editors each month. Following are our top picks for July.

MOD-TWIN 225 CLUTCH KIT FOR SUBARU WRX STI

Advanced Clutch Technology (ACT)
advancedclutch.com

Thanks to its modular construction, the new Mod-Twin 225 clutch is available in one of 10 configurations for the Subaru WRX STi—including three different clamp loads—so it’s well-suited for high-horsepower applications on the street, strip, or road course. The key component is a single mono-drive hub designed to reduce stress on the drivetrain.

“Turbo four-cylinder engines have a lot of torsional vibration and are notorious for being hard on clutches. They will strip out the splines and hubs,” explained Rich Barsamian. “What’s really needed is a sprung hub to dampen the torsional vibration.”

There isn’t much room to add springs to the hub, so ACT developed a mono-drive hub that’s sprung and supports two discs. The clutch is also available in a rigid construction for street and race applications. Depending on the configuration, the Mod-Twin 225 will support between 700 and 1,340 lb-ft of engine torque.

“It’s really designed for the gearhead making a ton of power,” said Barsamaian. “When people try it, they’re impressed. They were expecting a heavy pedal feel. This clutch holds the power but is a treat to drive.”

The clutch uses the factory pull-type design and simple installation. The kit includes chromoly flywheel, ARP clutch bolts, and an alignment tool. The kit also works with the Mitsubishi Evo engine. —Mike Magda

SB/09 SHORT-TRACK SHOCK ABSORBER

JRi Shocks
jrishocks.com

The new SB/09 short-track shock absorber from JRi Shocks is available in an aluminum body for short-track asphalt racing. It also comes in a steel body that is legal in dirt-track modified and other classes that don’t allow alloy construction.

It’s a small-bore shock with a .500-inch OD shaft. Multiple piston options are available, including linear, high-flow and linear digressive.

“With approximately 60 clicks of rebound, compression or bleed adjustment—depending on jetting—and a base valve design, the SB/09 is ideal for a wide range of short-track applications,” said Candace Martin.

The shocks can be set up for coil-over operation with spring sizes ranging from 2.5- to 5-inch in diameter, and teams can order it with a stroke distance of 5 to 9 inches. JRi also offers a shim kit and SB/09-specific wrench to adjust the shocks for different track conditions. —Mike Magda

123-MM HIGH BOOST THROTTLE BODY

Wilson Manifolds
wilsonmanifolds.com

When Wilson Manifolds originally developed a 123-mm billet throttle body, boost pressures were in the 10- to 20-psi range. “Now they’re running over 60 pounds,” said Keith Wilson. 

That prompted the company to design a much beefier model with the same dimensions that’s an easy swap with the old model.

“We’ve gone to a double-sealed shaft that holds up to 100 pounds of pressure without leaking,” noted Wilson. “Even though we went to a larger shaft and gained a lot of strength, we lost no flow.”

The massive .625-inch stainless-steel shaft is aerodynamically shaped, and the blade is tapered to enhance airflow without giving up strength. The blade is fastened to the throttle shaft with aircraft quality hardware that is Loctited and peened to assure positive retention. The TPS engagement is precision fit and compatible with either Ford or MoTeC sensors. Finally, there’s a two-way adjustable linkage system.

The 5-inch V-band inlet and outlet make the new throttle body a direct replacement to the original 123-mm throttle body.

“A lot of racers have gone to a crank-driven blower, and we wanted to make a throttle body that’s as safe as possible,” added Wilson, noting that this same design is also available in a 105-mm size. —Mike Magda