Honda Civic Engine Mount Selection Guide

Why Engine Mounts Matter on a Civic

Engine mounts secure the powertrain to the chassis while isolating engine vibrations from the cabin. The factory mounts on every Civic generation are engineered for comfort first. They use fluid-filled or rubber isolation chambers with large voids that allow significant engine movement under load. On a stock Civic, this is barely noticeable. Once power levels increase — even with a basic intake and tune — the stock mounts allow enough drivetrain movement to cause wheel hop during hard launches, vague shift feel, and exhaust or intake components contacting the chassis.

Stiffer aftermarket mounts reduce or eliminate that movement. The trade-off is noise, vibration, and harshness (NVH) transferred into the cabin. The choice comes down to how the car is used: a daily driver that sees occasional pulls needs a different stiffness than a dedicated track car running slicks.

This guide covers the durometer scale, the Hasport lineup (the dominant Civic mount manufacturer), platform-specific options from 8th gen through FL5, full kit versus rear-mount-only strategy, NVH expectations at each stiffness level, and other brands including Innovative Mounts and Boomba Racing.

Understanding the Durometer Scale

Aftermarket polyurethane mount Bushings are rated on the Shore A durometer scale. A lower number means a softer bushing with more vibration absorption but more engine movement. A higher number means less movement and more vibration transfer. The scale is not linear — the jump from 70A to 88A represents a much larger stiffness increase than from 62A to 70A.

The 62A bushing is similar in material hardness to the stock rubber bushing, but without the large isolation voids that allow the stock mount to flex. This is why a 62A aftermarket mount provides substantially more engine control than a stock mount despite the similar durometer — the design eliminates the gaps that allow movement, not just the material stiffness.

For 9th gen Civics, Innovative Mounts uses a slightly different scale: 75A (equivalent to roughly Hasport 70A for street performance), 85A (equivalent to roughly Hasport 88A), and 95A (competition grade). The differences are small enough that the application matters more than the exact number.

Hasport Mount Kit Options by Generation

Hasport is the dominant manufacturer for Civic engine mounts, offering full replacement kits and individual mounts for every generation. All Hasport polyurethane mounts are made in the USA with billet aluminum brackets and urethane bushings available in all four durometer levels.

*The FL5 Type R and 11th gen Civic share the rear mount part (FERR). The left and right mounts in the FL5STK kit are specific to the K20C1 engine bay layout.

Rear Mount Only vs Full Kit

Hasport explicitly recommends a rear-mount-only upgrade for daily drivers. The rear mount controls the majority of fore-aft engine movement and wheel hop without adding the NVH penalty of replacing the left and right mounts. The factory left and right mounts retain their hydraulic fluid damping, which absorbs low-frequency vibrations that the polyurethane rear mount cannot.

A rear-mount-only upgrade costs approximately $150-190 depending on the platform and durometer. It takes roughly 30-60 minutes to install on all generations. For a bolt-on Civic Si running up to 280-300 whp, the rear mount alone is sufficient to eliminate wheel hop and improve shift feel.

A full three-mount kit (left, right, rear) costs $500-710 and is recommended when:

• Power exceeds 300 whp and the engine has enough torque to overwhelm the stock side mounts
• The car sees regular track use with sticky tires
• The car is built with a larger turbo that creates more torque AT lower RPM
• The owner is willing to accept significantly more cabin vibration for maximum drivetrain control

On the FL5 Type R, Hasport states: “If you are looking for a stock ride we suggest replacing only the rear mount. This will control the majority of the engine movement without the harshness of the full kit. It will also extend the life of the left and right mounts.”

NVH Expectations at Each Stiffness Level

NVH is subjective, but the pattern across all platforms is consistent. The most important factor is idle vibration — the engine shakes most at low RPM, and stiffer mounts transmit that directly through the chassis. Once the car is moving above 2,000 RPM, the difference narrows because road noise and engine speed mask the vibration.

62A (Street): Nearly undetectable NVH increase over a healthy stock mount. Some owners report no noticeable cabin vibration after the 500-1,000 mile break-in period. On 9thgencivic.com, an owner who swapped from 70A to 62A described the 62A as “basically stock bushing stiffness” but with a “substantial difference in engine movement” because the stock mount gaps are eliminated. One 8th gen owner on a 2011 Si reported that 62A actually showed more cabin vibration than 70A in their specific installation, which highlights how individual chassis and engine conditions affect NVH.

70A (Race): Noticeable vibration at idle, especially in gear with the clutch engaged. The steering wheel and shift knob vibrate perceptibly. The vibration attenuates once the car is moving. Most owners who run 70A say the NVH is tolerable after a week of driving. On the 9th gen, an owner reported: “I have the 70a rear mount and the vibrations are very minimal. Sometimes I feel like it should be stiffer.” However, other owners describe the 70A as significantly more intrusive than 62A, particularly on cold starts. Saikospeed summarizes 70A as “not recommended for comfort-focused drivers.”

88A (Extreme Race): Mirrors visibly shake at idle. The entire cabin buzzes at low RPM. The vibration is constant and intrusive. Saikospeed states: “Vibrations are very noticeable, especially at idle, but the gains in drivetrain stability and launch consistency make them worth it for hardcore builds.” On a daily driver, the 88A rear mount alone can make the car unpleasant in stop-and-go traffic.

94A (Most Extreme Race): Race-grade vibration. Hasport describes it as causing “significant noise and vibration in the car chassis.” This is not a daily driver mount. The only reason to choose 94A is a competition car where absolute engine control matters more than comfort.

Boomba Racing Torque Dampers

Boomba Racing offers a different approach for the 8th and 9th gen Civic Si. Instead of full replacement mounts, Boomba sells torque damper sets that replace the upper and lower dogbone mounts. These are the small linkage-style mounts that connect the engine to the chassis near the top of the engine bay.

Boomba’s 9th gen Si torque damper set costs $282 and eliminates wheel hop completely according to the manufacturer. The design uses solid polyurethane bushings in an aircraft-grade aluminum housing. Owner feedback confirms that Boomba mounts are effective but vibrate noticeably. One owner described the feeling as “the motor is welded to the chassis.” Another described the trade-off: “However, keep in mind there will be a large increase in cabin vibrations as a trade off. I personally think Boomba should have gone slightly less stiff on the mount bushings.”

Boomba mounts require a 1,000-2,000 mile break-in period before the NVH settles. Some owners report that the initial vibration decreases significantly after break-in. Boomba offers mounts for the 8th gen Si at $383 (full kit) and the 9th gen Si torque dampers at $282.

Boomba mounts do not replace the rear or side engine mounts — they only replace the torque rod mounts. This means they control engine twist under load but do not address fore-aft movement the way a rear mount replacement does. For maximum control, some owners combine a Boomba torque damper set with a Hasport or Innovative rear mount.

Innovative Mounts

Innovative Mounts offers rear engine mounts for the 9th gen Civic Si at a lower price point than Hasport. The 9th gen rear mount costs $134.99-145.79 depending on durometer choice. Innovative uses a three-tier durometer system:

• 75A (Black): Rated for 250-400 HP. Street-focused, similar to Hasport 62A-70A range.
• 85A (Grey): Rated for 400-500 hp. Track-focused, similar to Hasport 88A.
• 95A (Red): Rated for 500+ hp. Competition only, similar to Hasport 94A.

Innovative mounts come with a lifetime warranty and use what the company describes as “no-tear vibration minimizing bushings.” The design is a direct replacement with no modification required. Owner feedback on 9th gen Civics is generally positive, with the 75A option recommended for daily-driven cars.

Break-In Period and What to Expect

All polyurethane engine mounts require a break-in period. During the first 500-1,000 miles, the urethane bushing will feel noticeably stiffer and vibrate more than it will after break-in. The bushing material compresses slightly and conforms to the mounting points, which reduces NVH over time.

Key break-in facts:

• Cold weather stiffens polyurethane, making NVH worse in winter months. Some owners report that their 70A mounts feel significantly softer in summer.
• The vibration is most noticeable at idle in gear with the clutch engaged. Neutral reduces it substantially.
• AC compressor engagement increases idle vibration on all stiffness levels because the engine load varies.
• After break-in, the NVH typically decreases by 30-50% from initial installation. This is consistent across Hasport, Innovative, and Boomba mounts.
• Some owners never fully adapt to the NVH of 88A or higher mounts on street cars. Testing a friend’s car with the same mount durometer before purchasing is recommended.

Recommended Mount Selection by Build Type

Stock or bolt-on daily driver (under 250 whp): Hasport rear mount in 62A. This is sufficient to eliminate wheel hop on street tires and improve shift feel without making the cabin unpleasant. Cost: $150-190. Installation difficulty: easy (30 minutes).

Stage 2 daily with occasional autocross (250-320 whp): Hasport rear mount in 70A, or 62A if NVH sensitivity is a concern. The 70A provides noticeably better engine control on sticky tires. Combined with a mild clutch upgrade, the 70A rear mount transforms the driving feel without being objectionable in daily driving. Cost: $150-190.

Track-focused car or high-horsepower build (350+ whp): Full Hasport mount kit in 70A or 88A depending on track use. The full kit prevents the engine from shifting under high lateral G-forces in corners, which a rear-mount-only setup cannot fully address. The 70A kit is acceptable for street-driven track cars. The 88A kit is for cars that trailered to events. Cost: $635-705.

Drag car on slicks: Full Hasport kit in 88A or 94A. The launch forces from slicks will overwhelm softer mounts and cause wheel hop that can damage axles. The full kit combined with solid Subframe collars provides the most consistent launches. Cost: $635-705 plus subframe collars.

Budget-conscious daily driver (8th/9th gen): Boomba torque dampers for $282 (replaces upper/lower dogbone mounts) combined with stock side/rear mounts. This addresses the most visible engine movement under load while keeping cost low. The NVH is moderate after break-in. Alternatively, an Innovative rear mount at $135 for the 9th gen offers the lowest-cost entry to proper engine control.

11th gen or FL5 owner wanting stock-like ride: Hasport FERR rear mount in 62A ($188.89). This is the manufacturer-recommended approach for preserving ride quality while gaining wheel hop control. Do not install the full kit unless the car is seeing regular track time.

☐ Engine Mount durometer is rated on the Shore A scale — lower numbers (62A) mean less vibration but more engine movement; higher numbers (94A) mean maximum control but severe NVH
☐ Hasport is the dominant Civic mount manufacturer, offering full kits ($635-705) and individual rear mounts ($150-190) for every generation from 8th gen to FL5
☐ A rear-mount-only upgrade in 62A or 70A is sufficient for most daily-driven bolt-on Civics up to approximately 300 whp
☐ A full three-mount kit is recommended for track cars, cars on sticky tires, or builds exceeding 300 whp where the side mounts are overwhelmed
☐ 62A mounts add nearly undetectable NVH while substantially reducing engine movement compared to stock — Hasport recommends this for daily drivers
☐ 70A mounts provide noticeably better engine control with moderate idle vibration that most owners find tolerable after break-in
☐ 88A and 94A mounts cause mirror-shake NVH and are not recommended for daily-driven street cars
☐ Boomba Racing torque dampers ($282-383) eliminate wheel hop on 8th and 9th gen Si but add moderate to high cabin vibration
☐ Innovative Mounts offers a lower-cost rear mount for the 9th gen Si ($135-145) with a 75A/85A/95A durometer system
☐ All polyurethane mounts require a 500-1,000 mile break-in period before NVH settles to its final level
☐ Cold weather increases polyurethane stiffness and NVH — mounts feel noticeably softer in summer
☐ Full mount kits from Hasport include a lifetime warranty on brackets and billet aluminum components