ACT HD/Race Rigid 6 Pad Clutch Kit
ACT NS1-HDR6 is a race-only clutch for the Nissan SR20DET turbo four: a rigid-hub, six-pad ceramic disc behind ACT's Heavy Duty pressure plate. ACT publishes it for the Japanese-market Silvia K (S13 and S14), the Silvia Spec-R (S15) and the Bluebird. It is the kit for an SR20 that does clutch kicks at drift events, repeated drag launches or time-attack sessions, where a sprung disc or an organic face keeps cooking.
The SR20DET makes its torque on boost, and in a drift or drag car that torque gets dumped into the clutch hundreds of times a day. NS1-HDR6 answers with a disc that has no hub springs at all. A rigid hub saves weight and space, transfers the engine's torque directly and does not wear out springs under repeated shock loads, which is why race builders choose it. The trade-off is that the driveline loses its cushion: ACT lists increased gear rattle for this kit and notes that the rigid design may increase spline wear on the input shaft and disc hub.
Six separate ceramic pads give a high friction coefficient and tolerate heat that glazes organic material. The N015 Heavy Duty plate keeps the pedal at a light to moderate effort. ACT rates the kit at 475 ft-lb, 90 percent over the original clutch, with a 240 mm (9.4 in) disc and a 1 in input shaft. Within the NS1 family, the NS1-HDG6 uses the same plate and torque rating with a sprung hub for a car that also sees street miles, and the NS1-XTR6 pairs this rigid disc with the Xtreme plate for higher boost levels.
Many SR20 clutch complaints are hydraulic. A tired master or slave cylinder, a cracked line or air in the system can cause poor release or a pedal that changes height. Bleed and inspect those first, and check the bellhousing for oil from the rear main seal. Then do a fourth-gear pull from low rpm under full boost and watch whether revs climb faster than road speed. Our slipping diagnosis guide walks through that load test, and organic vs. ceramic clutch discs explains whether a race disc is really what your car needs.
Our listing does not name a vehicle, so here is what ACT publishes for NS1-HDR6: the 1990-1998 Nissan Bluebird SSS Attessa 2.0L turbo, the 1991-1998 Silvia K (S13 and S14) with the five-speed and the 1999-2002 Silvia Spec-R (S15) with the six-speed, all SR20DET. ACT lists no US-model application. For a US 240SX swapped to an SR20DET, fitment depends on the transmission and flywheel used in the swap, so send us the engine, gearbox and flywheel details before ordering. A 240SX still on the KA24 needs a different kit, such as the NX1-HDG6. Gearbox concerns on those chassis are covered in our 240SX five-speed problems guide.
| Brand | ACT |
| Part number | NS1-HDR6 |
| Fits | ACT HD/Race Rigid 6 Pad Clutch Kit |
| Type | Clutch Kits - Single |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
No. ACT recommends it for race use only. The rigid hub passes more driveline shock and gear rattle, and the six ceramic pads engage quickly. For a mixed street and event car the sprung NS1-HDG6 is the better choice.
Both use a rigid six-pad ceramic disc. NS1-HDR6 has the Heavy Duty plate rated at 475 ft-lb with a lighter pedal, while NS1-XTR6 uses the Xtreme plate for more clamp load and a heavier pedal.
ACT lists it only for the JDM SR20DET Silvia S13, S14, S15 and Bluebird. A US 240SX with an SR20DET swap may use it depending on the gearbox and flywheel in the swap. KA24 cars need a different kit such as the NX1-HDG6.
No. The kit includes the pressure plate, disc, release bearing, pilot bushing and alignment tool. Resurface your flywheel or buy a new one.
Without hub springs, every torque spike hits the disc hub and input shaft splines directly. ACT notes the rigid design may increase spline wear, so check the input shaft at each clutch change.
