ACT XT/Perf Street Sprung Clutch Kit
The ACT NS1-XTSS is the clutch kit for an SR20DET owner who has turned the boost up and wants the clutch to stop slipping without moving to a grabby puck disc. ACT builds this number for the turbo 2.0L SR20DET in the Nissan Silvia K (S13/S14), the Silvia Spec-R (S15) and the Bluebird SSS Attessa. If your car flares in third or fourth when the turbo comes on, smells hot after a few pulls, or the stock clutch is simply worn out, this is the street-friendly way to add holding power.
The kit pairs ACT's Xtreme pressure plate (N015X) with a Performance Street sprung disc (3000405). The Xtreme plate uses a stiffer diaphragm for much higher clamp load, while the disc stays organic: a full-face, copper-rich lining on a steel backing with a sprung hub. That combination is why ACT rates it at 445 ft-lb at the crank, 78 percent over the original clutch, while keeping smooth engagement and close-to-stock gear rattle. The disc is 240 mm (9.4 in) on a 1.0 in input spline.
Compared with the other NS1 kits: the NS1-HDSS uses the lighter Heavy Duty plate with the same style of organic disc for a softer pedal, and the NS1-XTG6 puts the same Xtreme plate on a 6-pad ceramic disc for 565 ft-lb but a far harsher take-up. The XTSS sits in between: big clamp, daily-drivable friction.
Do a load test in fourth from low rpm at full boost. If the tach climbs faster than the road speed, the clutch is slipping. Before pulling the transmission, rule out the hydraulics: a soft pedal, a leaking slave cylinder or old fluid can keep the clutch from fully releasing, which shows up as grinding into gear rather than slip. Our transmission slipping diagnosis guide covers the load test, and shift flare vs. slip explains how to tell true slip from other drivetrain complaints.
ACT lists this kit for the Japanese-market SR20DET only: 1990-1998 Nissan Bluebird SSS Attessa 2.0L turbo, 1991-1998 Silvia K (S13/S14) 2.0L turbo 5-speed RWD, and 1999-2002 Silvia Spec-R (S15) 2.0L turbo 6-speed RWD. It is also the common choice for US 240SX chassis that have been swapped to the SR20DET with its own transmission. A 240SX still running the KA24 and its original transmission takes a different clutch, so check that before ordering. If you are unsure which flywheel and transmission are in the car, send us the chassis, engine and transmission details and we will confirm. More clutch and flywheel options are in our rebuild kits and clutch collection.
Resurface the flywheel or replace it; a glazed or heat-checked surface will make any new clutch chatter. If you want a lighter option, the SPEC SR20DET aluminum flywheel or the Competition Clutch 10.28 lb steel flywheel pair well. Install the new PB1012 pilot bushing, center the disc with the AT01 tool, and torque the pressure plate bolts evenly in a star pattern. Bleed the clutch hydraulics with fresh DOT 3 or DOT 4 brake fluid. ACT recommends 300 to 500 miles of mild, stop-and-go break-in on organic discs before hard launches, and warns against overheating the clutch during that period. Expect the Xtreme plate to raise pedal effort noticeably over stock; ACT puts the increase for Xtreme plates at roughly 50 to 80 percent depending on the car.
| Brand | ACT |
| Part number | NS1-XTSS |
| Fits | ACT XT/Perf Street Sprung Clutch Kit |
| Type | Clutch Kits - Single |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
ACT lists it for the SR20DET Silvia and Bluebird. It fits a 240SX that has been swapped to an SR20DET with the SR20 transmission. A 240SX with the KA24 engine and its factory transmission needs a different kit.
ACT rates the NS1-XTSS at 445 ft-lb measured at the crank, 78 percent over the original clutch.
ACT describes it as moderate to heavy, with smooth engagement. The Xtreme plate typically adds 50 to 80 percent pedal effort over stock depending on the car.
Resurface or replace the flywheel, use the new pilot bushing and release bearing in the kit, and inspect the slave cylinder and clutch fork pivot while the transmission is out.
Yes. ACT recommends 300 to 500 miles of gentle driving on organic street discs before racing or hard launches.
