Description

ATI Super Damper Mitsubishi Evo 8/9 4G63 — Part #ATI-918250

Firstly, Buy ATI Super Damper Mitsubishi Evo 8/9 4G63, Part #ATI-918250. 6.325-inch, 6-rib. The ATI Super Damper Mitsubishi Evo 8/9 4G63 is a high-performance harmonic damper designed specifically for Mitsubishi Lancer Evolution VIII and IX 4G63 engines. Part #918250 is engineered for high-horsepower street and race applications, helping control torsional crankshaft vibrations and protect the 4G63 engine from harmful harmonics across the RPM range. ATI identifies this Super Damper as a direct replacement for the factory-style damper while incorporating a specialized steel hub and multi-ring damping design.

Unlike a simple lightweight crank pulley, the ATI Super Damper is designed as a true harmonic damper. The system uses ATI’s “damper within a damper” design to control crankshaft torsional vibration. This makes it particularly relevant for modified 4G63 engines that see higher RPM, increased cylinder pressure, and demanding street or track use. ATI also states that the Evolution VIII and IX version exceeds SFI 18.1 requirements for competition applications.

ATI Super Damper Mitsubishi Evo 8/9 4G63 Features

The ATI Super Damper Mitsubishi Evo 8/9 4G63 combines a precision-machined aluminum outer shell with a steel timing-gear hub. The 918250 uses a 6.325-inch diameter, six-rib serpentine drive, and is approximately 12% overdriven compared with the OEM damper. ATI lists the complete damper at approximately 6.3 lb, with an inertia weight of approximately 2.4 lb.

Firstly, the damper is specifically designed for the Mitsubishi Evolution 4G63 platform. Secondly, its internal damping system is intended to reduce torsional crankshaft vibration rather than simply reducing rotating mass. Thirdly, the integrated timing-gear hub replaces the factory timing gear and provides the mounting arrangement required for the Evo application.

Buy ATI Super Damper Mitsubishi Evo 8/9 4G63, Part #ATI-918250. 6.325-inch, 6-rib, 12% overdriven harmonic damper for high-performance 4G63 engines.

Product Specifications

• Brand: ATI Performance Products
• Product: Super Damper / Harmonic Damper
• Part Number: 918250 / ATI-918250
• Application: Mitsubishi Evo 8/9 4G63
• Engine: Mitsubishi 4G63 MIVEC
• Outer Diameter: 6.325 inches
• Material: Aluminum shell
• Hub Material: Steel
• Hub: ATI #916025
• Bore: 1.263 inches
• Drive: 6-rib serpentine
• Drive Ratio: 12% overdriven
• Timing Marks: Laser-etched
• Certification: SFI 18.1
• Inertia Weight: Approximately 2.4 lb
• Complete Damper Weight: Approximately 6.3 lb

Designed for Mitsubishi Evo 8 and Evo 9 4G63 Engines

ATI specifically identifies part 918250 for the Mitsubishi Evolution VIII and IX 4G63. The manufacturer’s current catalog lists the Evo 8 & 9 application with a 6.325-inch aluminum damper, six ribs, steel #916025 hub, and approximately 6.3 lb total weight.

The 4G63 is well known for its high-RPM performance capability, making crankshaft vibration control an important consideration for serious engine builds. A properly designed harmonic damper can help manage torsional vibration within the crankshaft assembly, particularly when an engine is being used under demanding conditions.

Specialist Evo parts suppliers also list the 918250 for Evolution VIII and IX applications and describe it as a direct replacement for the stock OEM damper.

High-Performance Crankshaft Vibration Control

The primary purpose of the ATI Super Damper is to manage torsional crankshaft vibration. Every internal-combustion engine generates torsional vibration as combustion pulses travel through the crankshaft. At higher RPM and power levels, controlling these vibrations becomes increasingly important for a performance engine.

The ATI Super Damper uses a multi-ring construction designed to absorb and control these torsional forces. ATI describes the Evolution damper as being suitable for high-horsepower street and race use while protecting against engine harmonics.

This makes the 918250 a useful upgrade for Evo owners building a high-power 4G63, preparing an engine for track use, or replacing an original damper during a comprehensive engine rebuild.

Installation and Belt Requirements

The ATI 918250 is designed around the Evo’s factory-style serpentine belt arrangement, but there are important installation considerations. ATI states that the custom timing-gear hub replaces the stock timing gear and that the lower timing cover must be trimmed for hub clearance.

ATI also specifies Carquest/Gates K060715 for the correct belt length with this damper because the 918250 is approximately 12% overdriven relative to the OEM damper.

Before installation, inspect the crankshaft snout, crankshaft pulley bolt, washer, timing components, belt condition, and surrounding timing-cover components. Proper installation should follow ATI’s supplied instructions and the appropriate Mitsubishi service procedures.

ATI 918250 for Street and Race Builds

The ATI Super Damper Mitsubishi Evo 8/9 4G63 is suited to a wide range of performance applications. It can be used on a modified street Evo, a high-horsepower build, or a competition-focused 4G63 engine where crankshaft harmonic control is an important part of the overall engine package.

The SFI 18.1 certification is particularly relevant for competition vehicles where certified crankshaft damper equipment is required. ATI states that its Evolution Super Dampers exceed SFI 18.1 specifications and are approved for NHRA and IHRA competition applications.

For a street-focused Evo, the damper can also provide an upgraded alternative to a standard factory damper when the engine is being rebuilt or upgraded. The key advantage is that the 918250 is engineered specifically around the Mitsubishi 4G63 Evolution platform rather than being a universal harmonic damper.

OEM Replacement Versus Performance Damper

The ATI 918250 is described as a direct replacement for the stock OEM damper, but it should not be confused with a basic OEM replacement pulley or lightweight underdrive pulley. Its primary purpose is harmonic control and crankshaft protection rather than simply changing accessory-drive speed or reducing pulley weight.

The damper’s integrated timing-gear hub, multi-ring design, aluminum shell, and SFI certification make it a dedicated performance component for the 4G63 platform.

If you are rebuilding a Mitsubishi Evo 8 or Evo 9 engine, upgrading the crankshaft damper can be considered alongside other engine components such as forged pistons, connecting rods, bearings, timing components, and crankshaft hardware.

Frequently Asked Questions

What is ATI part number 918250?

ATI 918250 is the Super Damper harmonic damper designed for Mitsubishi Evolution 8 and 9 4G63 engines. ATI identifies it as the Evo 8 & 9 Super Damper in its Mitsubishi application information.

What engine does ATI 918250 fit?

The 918250 is designed for the Mitsubishi 4G63 MIVEC engine used in the Evolution VIII and IX. Some specialist suppliers list the same part more broadly for Evolution IV–IX 4G63 applications, so verify the specific engine and timing-cover configuration before ordering.

What size is the ATI 918250?

The ATI 918250 has a 6.325-inch outside diameter and a six-rib serpentine drive. ATI lists it as approximately 12% overdriven compared with the OEM damper.

Is the ATI 918250 SFI certified?

Yes. The ATI 918250 is listed as SFI 18.1 certified, making it suitable for applicable competition environments requiring an SFI-certified harmonic damper.

Does the ATI 918250 require timing-cover modification?

Yes. ATI states that the custom timing-gear hub replaces the stock timing gear and that the lower timing cover must be trimmed for clearance.

What belt should be used with ATI 918250?

ATI recommends Carquest/Gates K060715 for the correct belt length with the Evo 8/9 918250 Super Damper.

Is ATI 918250 a lightweight crank pulley?

It is better described as a performance harmonic damper rather than simply a lightweight crank pulley. Its purpose is to control torsional crankshaft vibration while providing the required accessory belt drive.

Can I buy ATI 918250 online?

Yes. The ATI 918250 is available through performance parts suppliers and is specifically marketed for Mitsubishi Evo 8/9 4G63 applications. If you’re upgrading the crankshaft assembly of a Mitsubishi Evolution, the ATI Super Damper Mitsubishi Evo 8/9 4G63 — Part #ATI-918250 provides a purpose-built performance harmonic damper with a 6.325-inch aluminum shell, integrated timing-gear hub, 12% overdrive, and SFI 18.1 certification, and you can buy this ATI Evo 8/9 4G63 Super Damper online at evomotorparts.com.

Buy ATI Super Damper Mitsubishi Evo 8/9 4G63, Part #ATI-918250. 6.325-inch, 6-rib, 12% overdriven harmonic damper for high-performance 4G63 engines.