Ferrea 98lbs Dual Valve Spring Kit - Porsche / 911 Turbo 996TT / 3.6L Turbo | S10122-X24

Actual part may differ from image above.


This Kit contains 24 Ferrea Dual Intake & Exhaust Valve Springs


Ferrea Valve Springs are developed from high strength alloys, including premium grade chrome silicon steel. These springs are manufactured with state-of-the-art equipment. Our springs are heat-treated and stress relieved, which dramatically increases the spring’s life.

The design and processes on these dual valve springs are optimized to reduce valvetrain harmonics and provide greater stability on high horsepower applications. We use high grade premium super-clean PAC alloy materials and maintain tight tolerances for those unique aftermarket cylinder heads.

Strict quality control procedures and cycle testing ensures consistency from batch to batch. Ferrea Valve Springs provide the stability needed for high lift, high rpm racing engines, while minimizing the load loss for today’s aggressive valvetrain combinations.


- Inner Spring OD 20.8mm
- Inner Spring ID 15.88mm
- Outer Spring OD 28mm
- Outer Spring ID 20.8mm
- Open Pressure 220lbs @ 24.5mm
- Max Lift 11.2mm
- Coil Bind 20mm
- Manufacturer Ferrea
- Valve Spring Type Dual
- Seat Pressure 98lbs @ 33.5mm
- Valve Spring Rate 309lbs/inch


This spring requires Ferrea Titanium Retainer # E11094 and Ferrea Spring Seat Locator # SL1099. (Discard OEM Spring Seat Locators) NOTE: Ferrea Seat Locators must be installed before valve seal installation and Max Net Lift is limited to 11.20 mm due to spring retainer and valve seal clearance.



Replaces OEM Part #  99-61-0-509-370 / 99 61 0 509 370 / 99610509370

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