ATI Super Damper – 6.78" Aluminum | Mitsubishi Eclipse 4G63 w/ Integral Lower Cam Drive

Protect your 4G63’s rotating assembly and unlock its full high-RPM potential with the ATI Super Damper — the industry standard in harmonic damper technology for performance and racing engines. Engineered specifically for the Mitsubishi Eclipse 4G63 with integral lower cam drive, this 6.78-inch aluminum damper replaces the factory rubber-bonded unit with ATI’s proven elastomer-based design, providing superior harmonic damping across a wider RPM range while adding dual 4-groove pulley tracks for accessory drive flexibility. A critical component for any serious 4G63 build.

Key Features:

• ATI Super Damper technology — elastomer-based harmonic damper engineered for superior vibration control across a wide RPM range
• 6.78-inch diameter aluminum construction — lightweight, precision-machined billet aluminum for strength and accurate balance
• Dual 4-groove pulley tracks — two independent 4-groove (serpentine) pulley surfaces for flexible accessory drive routing
• 4G63 integral lower cam drive specific — engineered for the Eclipse 4G63 variant with the lower cam drive integrated into the crankshaft
• Replaces factory rubber-bonded damper — eliminates the failure risk of aging OEM rubber bonding that degrades over time and at high RPM
• SFI certified — ATI Super Dampers meet SFI 18.1 specification for use in sanctioned motorsport
• Made in the USA — manufactured by ATI Performance Products in Baltimore, Maryland

Performance Benefits:

• Superior Harmonic Damping: ATI’s elastomer design provides more consistent, broader-range harmonic damping than factory rubber-bonded units — protecting crankshaft, bearings, and rotating assembly at high RPM
• High-RPM Reliability: Factory rubber-bonded dampers can slip, delaminate, or fail at sustained high RPM — ATI’s elastomer construction maintains integrity under the demands of performance and racing use
• Accessory Drive Flexibility: Dual 4-groove pulley tracks allow custom accessory drive configurations for race builds, including power steering delete, AC delete, or custom alternator routing
• Precision Balance: CNC-machined aluminum construction ensures accurate rotational balance, reducing vibration and protecting engine internals
• Longevity: Elastomer damping material maintains its properties far longer than factory rubber bonding — a one-time investment for the life of the engine build

Specifications:

• Brand: ATI Performance Products
• Part Number: ATI918251
• Diameter: 6.78 inches
• Material: Billet aluminum
• Pulley Configuration: 2x 4-groove (serpentine)
• Damper Type: Elastomer (Super Damper)
• SFI Certification: SFI 18.1
• Origin: Made in USA (Baltimore, Maryland)
• Application: Mitsubishi Eclipse 4G63 w/ Integral Lower Cam Drive

Fitment Information:

• Mitsubishi Eclipse — 4G63 engine with integral lower cam drive
• Note: The 4G63 was used in multiple Mitsubishi and Eagle platforms. This damper is specific to the variant with the integral lower cam drive — verify your specific engine configuration before ordering. Not all 4G63 applications use the integral lower cam drive.
• Installation: Professional installation strongly recommended — crankshaft damper installation requires proper torque specification and in some cases a harmonic balancer installer tool
• Timing: Verify timing marks after installation

What’s Included:

• ATI Super Damper – 6.78" aluminum, dual 4-groove (ATI918251)
• Installation hardware
• Installation instructions
• SFI 18.1 certification tag

Installation Notes:

• Professional installation strongly recommended
• Use a proper harmonic balancer installer tool — do not use an impact wrench to drive the damper onto the crankshaft snout
• Torque the crankshaft bolt to ATI’s specified torque value — do not use factory torque spec
• Verify timing marks after installation before starting the engine
• Inspect crankshaft snout for wear or damage before installation

Why Replace the Factory Damper?

The factory crankshaft harmonic damper uses a rubber-bonded design — an inner hub bonded to an outer inertia ring via a rubber layer. Over time and at sustained high RPM, this rubber bond degrades, hardens, and can delaminate — causing the outer ring to slip relative to the hub. When this happens, timing marks become inaccurate, harmonic damping is lost, and the crankshaft is exposed to destructive torsional vibrations that can cause bearing failure, crankshaft cracking, and catastrophic engine damage. For any performance or racing 4G63 build, replacing the factory damper with an ATI Super Damper is a critical reliability upgrade — not just a performance modification.

ATI Super Damper Technology:

ATI Performance Products pioneered the elastomer-based Super Damper design for performance and racing applications. Unlike rubber-bonded OEM dampers, ATI’s elastomer material maintains consistent damping properties across a wide temperature and RPM range, does not delaminate or slip, and can be rebuilt with fresh elastomer when the material eventually wears. The result is a damper that provides superior harmonic control throughout the engine’s RPM range — protecting the crankshaft and rotating assembly under conditions that destroy factory units.

The 4G63 Platform:

The Mitsubishi 4G63 is one of the most celebrated turbocharged four-cylinder engines in motorsport history — the engine that powered the Mitsubishi Lancer Evolution to multiple World Rally Championship titles and became a staple of drag racing, time attack, and circuit competition worldwide. The Eclipse’s 4G63 shares the same legendary block and head architecture, making it a popular platform for high-power builds. At elevated power levels and RPM, the factory harmonic damper becomes a liability — the ATI Super Damper is the professional solution.

Why ATI?

ATI Performance Products has been manufacturing harmonic dampers, torque converters, and transmission components for professional racing since 1966. Their Super Damper is the choice of NASCAR, NHRA, IMSA, and professional engine builders worldwide — a product with decades of motorsport validation behind it. For the 4G63, ATI’s application-specific damper is the definitive upgrade over the factory unit.

Perfect For:

• Mitsubishi Eclipse 4G63 builds running elevated RPM or sustained high-performance driving
• High-power 4G63 builds where factory damper reliability is a concern
• Race and time attack builds requiring SFI 18.1 certified damper components
• Engine rebuilds where the factory damper is being replaced as part of a complete rotating assembly refresh
• Anyone building a serious 4G63 who understands the consequences of a failed harmonic damper

Pro Tip: Replace the crankshaft damper any time you have the front of the engine apart for timing belt service. The incremental cost of the ATI Super Damper versus a factory replacement is minimal compared to the cost of engine damage from a failed OEM unit.

Note: Verify your 4G63 variant has the integral lower cam drive before ordering. This is a specific configuration — using the wrong damper on a different 4G63 variant will result in incorrect fitment.