Clutch Masters 12-13 Honda Civic Si 2.4L 6spd FX500 High Rev 6-Puck Rigid Ceramic Clutch...

The Clutch Masters 08240-HRB6-SK is the FX500, a rigid six-puck ceramic clutch with a steel flywheel for the 2012 to 2013 Honda Civic Si 2.4L six-speed. This is a race-only part. It is meant for drag, time attack and high-boost K24 Si builds where a sprung disc or a street clutch keeps slipping, and the owner accepts heavy pedal effort and an on-off engagement as the price of holding the power.

How the FX500 rigid clutch works in a 2.4L Civic Si

Clutch Masters quotes 200 to 400 percent more holding capacity than stock for the FX500 line. The extra clamp load comes from the Power Plus II pressure plate, which uses two stacked heat-treated diaphragms, heavy-duty straps and a high-leverage design. Clutch Masters describes the result as exceptionally high clamping force with heavy pedal pressure. The disc has a solid hub with no damper springs and no Marcel cushion, so there is nothing to soften engagement. Clutch Masters warns it engages and disengages instantly, chatters, and is not recommended for the street. The FX500 line is SFI certified to spec 1.2 for NHRA, IHRA, SCCA, NASA and other sanctioning bodies.

Like every 08240 K24 kit, this clutch runs on a Clutch Masters steel flywheel that is lighter than the factory part (Clutch Masters lists FW-037-SF for the 08240 series). That lighter flywheel is why Clutch Masters says a Hondata FlashPro or other engine management is mandatory. The stock flywheel cannot be reused. The SK package includes the steel flywheel, so the disc, pressure plate and flywheel arrive as a matched set.

Signs you need a race clutch rather than a street upgrade

• A sprung puck or Kevlar clutch already slips at peak boost or on a clutch-dump launch
• The disc glazes or overheats after a few passes or laps
• You are making power well beyond what street clutches are built to hold, on a car that rarely sees traffic
• Your class or track requires an SFI-certified clutch
• Usual wear signs on the old clutch: rising engagement point, burnt smell, bearing noise with the pedal pressed

Confirm the problem and the use case first

Before buying, prove the clutch is actually slipping: a full-throttle pull in a high gear with the tach running away from road speed is the classic sign. Check for fluid or oil in the bellhousing and a spongy pedal, since hydraulic faults and seal leaks look like clutch failure. Our slipping diagnosis guide walks through that process. Then be honest about how the car is used. If it is driven daily or sits in stop-and-go traffic, a rigid disc will be miserable; the FX400 sprung 6-puck kit with steel flywheel keeps the damper springs and is the street-and-strip compromise. For cost planning, see our manual transmission repair cost guide.

Fitment

Our listing is for the 2012 to 2013 Civic Si 2.4L six-speed. Clutch Masters application data for the 08240-HRB6 also covers the 2012 to 2015 Civic Si 2.4L six-speed, 2009 to 2014 Acura TSX 2.4L six-speed and 2013 to 2015 Acura ILX 2.4L six-speed. The 08240 number means a lighter-than-OEM flywheel and a required tune; Clutch Masters sells the same FX500 as 08320-HRB6 for cars staying on the factory ECU. If your car has an aftermarket flywheel already or a non-stock transmission, tell us before ordering. Send your year and VIN for a fitment check, and see more parts in the rebuild kits category.

Install notes

• Fit the included flywheel with new bolts at the Honda torque specification; do not reuse the factory flywheel.
• Load the FlashPro or equivalent calibration before driving so the lighter flywheel does not set a check engine light.
• Expect a much heavier pedal from the dual-diaphragm pressure plate. Check the clutch master and slave cylinders and pedal pivot for wear, since weak hydraulics show up fast under this load.
• Align the disc with the supplied tool and torque the pressure plate bolts gradually in a star pattern.
• Install the new release bearing, bleed with fresh DOT 3 and refill the gearbox with Honda manual transmission fluid.
• Instant engagement shocks the mounts. The 2012 to 2015 Civic Si and ILX engine and transmission mount kit keeps the drivetrain from rocking on launch.

Can I daily drive the FX500 in my Civic Si?

Clutch Masters labels the FX500 race only. The rigid hub engages instantly, chatters and has heavy pedal pressure, so it is a poor fit for traffic. The sprung FX400 is the better street and strip option.

Do I need a tune with the 08240-HRB6-SK?

Yes. The 08240 kits run a Clutch Masters steel flywheel lighter than OEM, and Clutch Masters says a Hondata FlashPro or other engine management is required to avoid a check engine light.

Is the FX500 SFI certified?

Clutch Masters states the FX500 line is SFI certified to spec 1.2 for competition in NHRA, NDRA, IDRC, IHRA, SCCA and NASA. Check your series rulebook for any extra requirements.

What comes in the kit?

Clutch Masters FX500 kits include the disc, pressure plate, throwout bearing, pilot bearing when applicable and an alignment tool. This SK version also includes the steel flywheel.

Will it fit a 2015 Civic Si or an ILX?

Clutch Masters lists the 08240-HRB6 for 2012 to 2015 Civic Si 2.4L six-speed, 2009 to 2014 TSX and 2013 to 2015 ILX 2.4L six-speed. Our listing is titled 2012 to 2013, so send your VIN for a check.

• Transmission Slipping Diagnosis Guide
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