Engineered for Honda K-Series engines equipped with compatible 5-speed or 6-speed manual transmissions, the Innovative Mounts 90640 replaces the factory rubber mounting arrangement with a durable steel assembly featuring a performance polyurethane bushing.

Factory engine mounts are designed to isolate engine vibration and provide a comfortable driving experience. However, the original rubber components can deteriorate, crack, or separate over time, allowing excessive drivetrain movement during acceleration, deceleration, and shifting.

The Innovative Mounts 90640 provides increased resistance to drivetrain movement, helping maintain more consistent engine and transmission positioning under load. Its firmer polyurethane construction can also help reduce unwanted drivetrain rocking and wheel hop during aggressive driving.

Featuring durable steel construction, CAD/CAM-engineered mounting geometry, stress-analyzed components, and Innovative Mounts' no-tear polyurethane bushing design, the 90640 is an excellent upgrade for daily-driven performance vehicles, modified K-Series engines, and dedicated motorsport applications.

Important: Part number 90640 is an individual front engine mount, not a complete engine mount kit or K-Series engine swap conversion kit.

Features

• Direct-Replacement Design: Replaces the factory front engine mount on compatible Honda Civic Si, Acura RSX, and Acura CSX applications.

• 2002–2006 Acura RSX Compatibility: Designed for supported RSX Base and Type-S models equipped with manual transmissions.

• 2002–2005 Honda Civic Si/Type-R Compatibility: Fits supported EP3 chassis applications.

• 2006–2011 Honda Civic Si Compatibility: Designed for compatible eighth-generation Civic Si applications.

• 2006–2011 Acura CSX Compatibility: Supports compatible Canadian-market Acura CSX configurations.

• Honda K-Series Engine Compatibility: Designed for supported K-Series engine applications.

• 5-Speed and 6-Speed Manual Transmission Support: Compatible with the manufacturer's specified manual drivetrain configurations.

• Front Mounting Position: Replaces the factory front engine mount.

• Steel Construction: Durable mounting assembly designed for performance applications.

• Performance Polyurethane Bushing: Provides increased resistance to drivetrain movement compared with conventional rubber mounts.

• No-Tear Bushing Design: Engineered to reduce excessive engine movement while retaining some vibration isolation.

• CAD/CAM Engineered: Designed for accurate fitment and consistent manufacturing quality.

• Stress-Analyzed Components: Developed for demanding drivetrain loads.

• Improved Drivetrain Stability: Helps control unwanted engine rocking during acceleration.

• Reduced Mount Deflection: Maintains more consistent engine and transmission positioning under load.

• Improved Drivetrain Response: Firmer mounting can provide a more connected drivetrain feel.

• Potential Wheel Hop Reduction: Reduced drivetrain movement may help minimize wheel hop during hard acceleration.

• Multiple Bushing Hardness Options: Available in 75A, 85A, and 95A configurations.

• Individual Replacement Mount: Allows upgrading the front mount without purchasing an entire engine mount kit.

• Lifetime Warranty: Backed by Innovative Mounts' lifetime warranty, subject to manufacturer terms.

Popular Performance Applications

Acura RSX Base and Type-S Performance Builds

Provides firmer front engine mounting for compatible RSX applications equipped with Honda K-Series engines and manual transmissions.

Honda Civic Si EP3 Upgrades

Replaces the factory front engine mount with a performance-oriented polyurethane mounting solution.

2006–2011 Honda Civic Si Performance Builds

Ideal for eighth-generation Civic Si owners looking to reduce excessive drivetrain movement during acceleration and shifting.

Acura CSX Performance Applications

Provides upgraded front engine mounting for supported Canadian-market Acura CSX models.

Naturally Aspirated K-Series Builds

Suitable for vehicles equipped with upgraded intake manifolds, headers, camshafts, and other naturally aspirated performance components.

Turbocharged K-Series Applications

Helps control excessive drivetrain movement in properly configured forced-induction applications.

Daily-Driven Performance Vehicles

The 75A bushing option provides increased drivetrain rigidity while retaining some vibration isolation for street-oriented builds.

Autocross and Road Racing

Reduced mount deflection helps maintain more consistent drivetrain positioning during acceleration, braking, and cornering.

Drag Racing Applications

Firmer polyurethane bushings help resist excessive engine movement during aggressive launches.

Worn Factory Mount Replacement

An excellent upgrade when the original rubber front engine mount has deteriorated, separated, or begun allowing excessive drivetrain movement.

Additional Information

• Manufacturer: Innovative Mounts
• Part Number: 90640
• Product Type: Front Engine Mount
• Mounting Position: Front
• Vehicle Application: 2002–2011 Honda Civic Si / 2002–2006 Acura RSX / 2006–2011 Acura CSX
• Chassis Compatibility: EP3 / DC5 / FG2 / Compatible Acura CSX
• Engine Compatibility: Honda K-Series
• Transmission Compatibility: 5-Speed or 6-Speed Manual
• Mount Construction: Steel
• Bushing Material: Performance Polyurethane
• Available Bushing Hardness Options: 75A / 85A / 95A
• OEM Replacement References: 50840-S6M-010 / 50840-S6M-J01 / 50830-SVB-A01
• Complete Mount Kit Reference: Innovative Mounts 90850 – 2006–2011 Honda Civic Si
• Engineering: CAD/CAM Designed and Stress Analyzed
• Manufacturer-Listed Weight: Approximately 3 lbs
• Warranty: Manufacturer Lifetime Warranty, Subject to Terms

Available Polyurethane Bushing Hardness Options

75A – Black – Street / Performance

The softest currently listed bushing option for the 90640.

Recommended for performance-oriented street vehicles where improved drivetrain stability is desired while retaining some vibration isolation.

Manufacturer horsepower guidance: approximately 250–400 HP.

85A – Grey – Performance / Race

Provides increased drivetrain rigidity for modified engines, aggressive driving, and competition applications.

Manufacturer horsepower guidance: approximately 400–500 HP.

95A – Red – Extreme Race

The stiffest listed polyurethane option, intended for high-output engines and dedicated racing applications.

Manufacturer horsepower guidance: 500+ HP.

These horsepower ranges are general manufacturer selection guidelines rather than guaranteed load ratings.

Important: Increasing bushing hardness generally increases noise, vibration, and harshness transmitted into the vehicle cabin. Select the appropriate bushing based on the vehicle's intended use and desired comfort level.

Innovative Mounts 90640 vs. 90850

Innovative Mounts 90640: Individual steel front engine mount for compatible Acura RSX, Honda Civic Si, and Acura CSX applications equipped with K-Series engines and manual transmissions.

Innovative Mounts 90850: Complete replacement engine mount kit for supported 2006–2011 Honda Civic Si applications.

The 90640 is an excellent choice when replacing or upgrading only the front engine mount.

Common Reasons for Replacement

• Cracked Factory Rubber: Aging rubber can deteriorate and allow excessive engine movement.

• Separated Mount Bushing: Worn factory mounts may develop excessive movement under load.

• Excessive Engine Rocking: Firmer polyurethane helps control unwanted drivetrain movement.

• Clunking During Acceleration: A worn front engine mount may allow excessive movement that results in noticeable drivetrain noise.

• Clunking During Gear Changes: Excessive drivetrain movement can contribute to noticeable movement during shifting.

• Reduced Drivetrain Stability: Performance polyurethane helps maintain more consistent engine positioning.

• Performance Engine Upgrades: Modified K-Series engines can benefit from firmer drivetrain mounting.

• Track and Racing Applications: Provides increased mount rigidity for demanding driving conditions.

• Individual Mount Replacement: Allows replacement of the front mount without purchasing a complete mount kit.

Installation Notes

1. Verify Vehicle Compatibility: Confirm that the vehicle is a supported Acura RSX, Honda Civic Si/Type-R, or Acura CSX application.

2. Confirm Transmission Type: Verify that the vehicle is equipped with a compatible 5-speed or 6-speed manual transmission.

3. Verify Mounting Position: The 90640 replaces the factory front engine mount.

4. Inspect the Existing Mount: Check the factory front mount for cracked rubber, separation, corrosion, or excessive movement.

5. Support the Drivetrain: Properly support the engine and transmission before removing the original front mount.

6. Remove the Factory Mount: Follow the applicable Honda or Acura service procedures.

7. Inspect Mounting Locations: Check the chassis and subframe mounting points for damage or corrosion.

8. Position the Innovative Mounts 90640: Install the replacement mount in the factory front mounting location.

9. Verify Mount Alignment: Ensure the mount and surrounding brackets are properly aligned without excessive preload or binding.

10. Install the Required Hardware: Use the hardware specified by Innovative Mounts and reuse applicable factory fasteners where instructed.

11. Torque Mounting Fasteners: Follow the applicable factory service manual and Innovative Mounts installation instructions.

12. Inspect Drivetrain Clearance: Verify that the engine and transmission do not contact surrounding chassis components.

13. Check for Additional Vibration: Some increase in vibration is normal when upgrading from factory rubber mounts to performance polyurethane.

14. Perform a Final Inspection: Verify proper mounting alignment and secure hardware before operating the vehicle.

15. Recheck After Initial Use: Inspect the mount and mounting hardware after the initial driving period.

Important: Innovative Mounts advises that installed mounts showing bolt impressions cannot be returned or exchanged. Confirm fitment before installation.

Professional installation is recommended.

What's Included

The Innovative Mounts 90640 includes:

• 1 × Innovative Mounts 90640 Steel Front Engine Mount Assembly

• 1 × Performance Polyurethane Bushing in the selected hardness configuration

Additional Information

This listing is for the individual front engine mount only.

The following components are not included unless separately specified:

• Driver-side transmission mount

• Passenger-side engine mount

• Rear engine mount

• Complete replacement engine mount kit

• Engine or transmission components

• Additional mounting hardware not specified by the manufacturer

Verify any required mounting hardware against the manufacturer packaging and installation instructions.

Upgrade your Honda Civic Si, Acura RSX, or Acura CSX with the Innovative Mounts 90640 Steel Front Engine Mount, engineered for compatible 2002–2011 Honda Civic Si, 2002–2006 Acura RSX, and 2006–2011 Acura CSX applications equipped with Honda K-Series engines and manual transmissions.

Featuring durable steel construction, CAD/CAM engineering, stress-analyzed components, performance polyurethane bushings, and a direct-replacement mounting design, the 90640 provides improved drivetrain stability and reduced excessive engine movement compared with worn factory rubber mounts.

Whether you're replacing a deteriorated OEM mount, upgrading a daily-driven K-Series vehicle, or preparing for aggressive track use, Innovative Mounts delivers a dependable performance mounting solution.