If you own a 2006–2011 Honda Civic Si sedan (FA5) and are looking to replace or upgrade the suspension, you may have come across the HFP (Honda Factory Performance) package. The HFP suspension was a dealer-installed option that lowered the car and improved handling. Knowing the exact FA5 HFP suspension part number is essential for getting the right components—whether you’re ordering from a dealer, an online OEM parts retailer, or a salvage yard. This guide covers everything you need to identify and source the correct OEM HFP parts for your FA5.
What Is the FA5 HFP Suspension?
The HFP suspension was offered as a performance package for the 8th‑generation Civic Si. For the FA5 sedan, the HFP kit included specific springs, dampers (struts and shocks), and sometimes a sway bar. The springs lowered the car approximately 0.6 inches in the front and 0.8 inches in the rear compared to the standard Si suspension. The dampers were re‑valved to match the springs, providing a firmer ride and better cornering.
This suspension was designed to be a factory‑approved upgrade, so it uses genuine Honda parts with unique part numbers. When you need to replace a worn strut or broken spring, using the correct FA5 HFP suspension part number ensures the ride height and handling remain as intended.
FA5 HFP Suspension Part Numbers List
The HFP suspension part numbers are specific to the FA5 chassis (4‑door sedan). The main components are:
Front Springs
- Part Number: 51401-SNA-A11 (HFP Front Spring)
- Note: This is the left/right (both sides use the same spring).
Rear Springs
- Part Number: 52401-SNA-A11 (HFP Rear Spring)
- Note: This spring also fits both rear positions.
Front Struts / Dampers
- Left Front: 51605-SNA-A11 (HFP Front Damper Left)
- Right Front: 51606-SNA-A11 (HFP Front Damper Right)
Rear Shocks / Dampers
- Left Rear: 52605-SNA-A11 (HFP Rear Damper Left)
- Right Rear: 52606-SNA-A11 (HFP Rear Damper Right)
Additional Components
- Some HFP kits also included a thicker rear sway bar (part number often 52300-SNA-A11), but that was optional. The springs and dampers are the core of the suspension.
These part numbers are for the OEM HFP components manufactured by Showa (the same supplier as the stock Civic Si). If you buy aftermarket replacements, you will not find these numbers—only the genuine HFP parts carry them.
How to Verify You Have HFP Suspension
Before ordering parts, confirm that your car actually has the HFP suspension. Look for:
- Silver or yellow paint dots on the springs (usually two bands of paint).
- A tag on the strut that says “HFP” or has a Honda part number.
- Ride height: HFP cars sit noticeably lower than standard Si’s, about 0.6–0.8 inches.
- VIN check: If you have the original window sticker or dealer invoice, look for “HFP Suspension” as an option.
If you’re buying a used car and the seller claims it has HFP, always inspect the part numbers on the springs/struts. Aftermarket springs (e.g., Eibach, H&R) look different and do not have Honda part numbers.
Where to Buy FA5 HFP Suspension Parts
Because HFP parts are genuine Honda accessories, they are available from:
- Honda dealership parts departments – most can order them, though some parts may be discontinued or on backorder.
- Online OEM parts retailers – websites like HondaPartsNow or Majestic Honda sell genuine parts at a discount. Use the part numbers above to search.
- Salvage yards / used parts – if you’re on a budget, look for FA5s being parted out. Verify the part numbers before buying.
Important: Avoid generic aftermarket struts that claim to be “HFP replacement.” They will change the ride height and handling. Stick to the OEM part numbers if you want to keep the original HFP characteristics.
Compatibility with Other Honda Models
FA5 HFP suspension parts are not interchangeable with the Civic coupe (FG2) or other trims without modifications. The sedan has different rear shock mounts and spring rates. However, the front struts and springs sometimes fit the FG2, but the rears will not. For the FA5, always use FA5-specific HFP part numbers.
Installation Tips
- Replacing HFP struts requires spring compressors—do not attempt without proper tools.
- Always replace top hats and bump stops when doing dampers. For HFP, the top hats are the same as the standard Si, but bump stops may differ. Use OEM Si bump stops (part numbers 51722-S5A-A01 for front, 52722-S5A-A01 for rear).
- After installation, get a professional alignment. HFP spec calls for slightly more negative camber than standard.
Final Recommendation
If your FA5 has HFP suspension and you need to replace a component, buy the exact OEM part using the FA5 HFP suspension part numbers listed above. This ensures correct fitment, ride quality, and originality. For budget builds, consider used OEM parts from a reliable source. If you want a different spring rate or adjustable dampers, look into aftermarket coilovers—but do not expect them to mirror the HFP feel. For most owners, maintaining the genuine HFP setup is the simplest and most reliable path.