Important KHC10 fitment distinction
EXEDY’s standard KHC10 clutch kit is commonly cataloged for the 2002–2006 Acura RSX Type-S and 2006–2011 Honda Civic Si. The broader Accord, TSX, RSX Base and 2012–2015 Civic Si coverage comes from pairing the clutch with a conversion-style EFT flywheel.
That distinction matters. This is not simply a KHC10 dropped onto every K20 and K24 flywheel Honda ever produced. The included flywheel is what makes the expanded application list possible.
Verify:
- Complete bundle part number
- Engine code
- Manual-transmission code
- Crankshaft bolt pattern
- Starter ring-gear position
- Flywheel trigger pattern
- Clutch diameter and spline count
- ECU requirements for the vehicle
The EXEDY USA website should be used to verify the clutch component, while the seller must confirm the EFT flywheel’s vehicle-specific compatibility.
What comes in the kit?
The package reportedly includes:
- EXEDY HCC539 pressure plate
- EXEDY HCD823 organic clutch disc
- EFT Pro-Lite 4140 chromoly flywheel
- Release or throwout bearing
- Pilot bushing
- Clutch alignment tool
- Installation guide
Published specifications
| Component | Specification |
|---|---|
| Clutch kit | EXEDY KHC10 |
| Pressure plate | HCC539 |
| Clutch disc | HCD823 |
| Disc diameter | 213 mm |
| Spline count | 24 |
| Friction material | Organic |
| Flywheel material | 4140 chromoly steel |
| Flywheel weight | Approximately 10.4 pounds |
| Warranty | Advertised as 12 months/12,000 miles |
Actual components may vary, so check every part number printed on the delivered boxes before removing the transmission.
OEM-style EXEDY clutch behavior
EXEDY is an original-equipment supplier to multiple vehicle manufacturers. The KHC10 kit uses an organic full-face disc intended to deliver progressive engagement and reasonable pedal behavior.
Expected characteristics include:
- Smooth street engagement
- Manageable pedal effort
- Low-speed modulation similar to an OEM clutch
- Low chatter from the clutch disc itself
- Suitable operation for stock or lightly modified engines
The KHC10 is not advertised here with a specific torque rating. Owners with forced induction, aggressive tuning or substantial torque increases should select a clutch with a documented capacity above the engine’s expected crank torque.
Read our performance clutch review for street and track before deciding whether an OEM-style organic clutch provides enough margin for your build.
What does the lightweight flywheel change?
The EFT flywheel weighs approximately 10.4 pounds, substantially reducing rotating mass compared with many factory K-series flywheels.
Potential benefits include:
- Faster engine response
- Quicker rev matching
- More immediate throttle changes
- Reduced rotating mass
- Sharper performance-oriented driving feel
There are also tradeoffs:
- Engine speed falls faster between shifts
- Smooth takeoffs require more careful throttle input
- Low-speed drivability may feel less forgiving
- Gear rollover noise may become more noticeable
- Stalling can be easier for inexperienced drivers
- Cruise behavior may differ from the factory calibration
A lightweight flywheel does not create substantial horsepower. It changes how quickly the engine accelerates and decelerates by reducing rotational inertia. That distinction may not sound as exciting in an advertisement, but physics has stubbornly refused to join the marketing department.
Why does the 2012–2015 Civic Si mention Hondata?
The 2012–2015 Civic Si uses the K24Z7 and an ECU strategy designed around its original flywheel behavior. The seller states that this flywheel conversion must be used with a Hondata Pro Flash.
A lightweight or conversion flywheel can affect:
- Crankshaft-speed fluctuation
- Misfire detection
- Rev-hang behavior
- Deceleration characteristics
- Idle stability
- Diagnostic trouble-code monitoring
Do not present the Hondata requirement as optional. Before installing this bundle on a ninth-generation Civic Si, obtain the exact required calibration from the seller or tuner and verify that it is appropriate for the vehicle’s ECU and modifications.
Visit Hondata for current tuning-platform information. Tuning should be performed by someone familiar with this exact flywheel conversion.
Best applications for this package
This kit is best suited to:
- Naturally aspirated K20 or K24 street builds
- Stock or mildly modified RSX and Civic Si models
- Accord or TSX owners wanting faster engine response
- Drivers who prefer an organic disc over a ceramic clutch
- Autocross or spirited street cars within OEM-style clutch capacity
It may not be appropriate for:
- High-torque turbocharged builds
- Dedicated drag vehicles
- Drivers expecting factory flywheel refinement
- Vehicles without a confirmed conversion application
- Ninth-generation Civic Si models without the required ECU solution
Explore additional Honda technical articles and Acura repair guides before planning the installation.
Installation recommendations
Because transmission removal represents most of the labor, inspect the surrounding components during installation:
- Rear main engine seal
- Transmission input-shaft seal
- Clutch master cylinder
- Slave cylinder
- Release fork and pivot
- Axle seals
- Engine and transmission mounts
- Flywheel and pressure-plate fasteners
Before installation:
- Confirm every clutch and flywheel part number.
- Compare the ring gear and crankshaft pattern with the original flywheel.
- Test-fit the clutch disc on the transmission input shaft.
- Clean the flywheel and pressure plate with residue-free brake cleaner.
- Install the disc in the correct orientation.
- Use new flywheel bolts when required by the service procedure.
- Tighten all fasteners using the proper sequence and torque.
- Complete any necessary ECU calibration before normal operation.
This package uses a new flywheel, so resurfacing the original unit should not be necessary.
Break-in procedure
Follow EXEDY and EFT’s supplied instructions. An organic clutch generally requires approximately 400–500 miles of moderate stop-and-go driving.
During break-in:
- Avoid hard launches
- Avoid full-throttle acceleration
- Stay out of boost when applicable
- Do not perform dyno pulls
- Avoid racing
- Do not slip the clutch excessively
- Use normal engagement cycles
Highway mileage alone does not provide enough clutch cycles for an effective break-in.
Final verdict
The EXEDY KHC10 and EFT Pro-Lite flywheel bundle offers an interesting combination: OEM-style clutch manners paired with the sharper response of a lightweight chromoly flywheel.
It can be a good fit for naturally aspirated and mildly modified K-series street cars, but the expanded application list depends on the included flywheel—not just the KHC10 clutch. Owners of a 2012–2015 Civic Si must also resolve the stated Hondata calibration requirement before installation.
Browse more drivetrain and performance products at ProStreetOnline or visit the My Pro Street technical library for additional K-series guides.


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