Mustang Motor Mounts: Stabilizing Your Engine

Most cars (Mustangs for sure) have rubber motor mounts. These mounts absorb a lot of the vibration, but allow for a lot of slop and loss of performance. Stock motor mounts are generally designed for one purpose. That purpose is to function as smoothly as possible for the end user. They are not concerned with performance and handling, but rather quietness and comfort. The reason being for that design is that is what the general population prefer. However, car enthusiasts are not a part of that general population. As a result, there are many different types of motor mounts that can be utilized to improve performance, even if it gives a little more NVH (Noise/Vibration/Harshness).

Generally, durometer polyurethane material is regarded as being stiffer than conventional rubber. While vibration will be felt more inside the car, the engine will not have as much play as compared to traditional rubber mounts. Additionally, poly mounts generally have a better tendency to last longer as compared to traditional rubber. Poly mounts have a harder time dry rotting when compared to traditional rubber.

Almost all motor mount kits come with polyurethane bushings, but some companies offer solid upgrade kits for their poly bushings. The solid upgrade kits usually consist of aluminum pucks that replace the polyurethane bushings and completely eliminate engine movement. While polyurethane bushings will add some additional noise, vibration, and harshness over stock, the solid mounts will add significantly more NVH. Generally speaking, it’s best to save the solid mounts for race applications, unless excess NVH isn’t a concern for you. 

Several manufacturers offer adjustable motor mounts as well, which can be extremely beneficial. Lowering your engine will lower the center of gravity on your Mustang, which can help you fine tune handling characteristics at the road course or in autocross competitions. A lower center of gravity will impact on instant center and anti-squat properties in drag racing applications. 

Not quite. While most of them can attach to multiple applications, there are some differences between generations. These can range from mounting location, to bolt size, to mount size, etc.

A daily driver can benefit from both mounts depending on their style and tolerances. If a daily driver is designed to be comfortable and easy going, then the stock mounts are more than acceptable for getting the job done. However, for racers, the daily driver might also be the race car. If it is a dual-purpose vehicle, poly mounts might be worth feeling the vibrations on the weekdays in order to have better handling on the weekends.

Generally speaking, yes, they can. The biggest issues that motor mounts can create is clearance with headers. While the mount itself is designed around the stock mount (dimensionally) the bolts that connect the motor mounts may not be. For example, on a 2005 Mustang GT, poly mounts can make the bolts hard to reach if combined with long tube headers. The header itself protrudes right over the bolt, making it extremely difficult to reach and tighten/loosen. In certain cases, getting a different head style for the bolts might be necessary in order to have proper clearances. At the same time, this can have issues with other parts of the engine itself, whether it be the block, plumbing, cooling system, etc. However, the vast majority of fitment issues clash with headers/exhaust manifolds.

The big benefit of replacing motor mounts is the change in vibration. With rubber mounts, there is a lot of play resulting in vibration being stronger and inconsistent with the vehicle. However, with poly mounts, the engine has a stronger connection to the frame and body of the car. As a result, the entire vehicle can take the vibration generated by the engine. This allows for wider distribution and generally results in better handling characteristics of the car as well. While it will feel like more vibration, this is because the distribution of the vibration is better than traditional rubber mounts. That being said, if the user wants little to no vibration to be felt, stick with rubber mounts.

Reducing engine deflection has several performance enhancing benenfits. Possibly the most important benefit is making high RPM shifting easier on manual transmission cars. The stock shifter is bolted to the chassis of your Mustang, so as the engine and transmission torque over under load with stock motor mounts, the shifter linkage becomes misaligned with the shifter and transmission, leading to gear lockout during aggressive driving.

Reducing engine movement can also make the car feel more responsive and composed when being pushed through corners. As your Mustang enters a corner with stock motor mounts, the engine will want to keep moving along its initial trajectory. The extra inertia of a 400-500 pound engine pushing or pulling on the nose of your Mustang can make front-end feel less responsive. As a car with upgraded motor mounts is thrown into the twisties, the nose of the car isn’t being pushed or pulled by the engine anymore. Since the engine is basically locked in place with upgraded mounts, it moves with the car and does not put up as much of a fight.

Many people choose to install motor mounts when they are installing long tube headers. Because the stock motor mounts are typically removed for extra room during a header install, installing upgraded mounts with long tube headers can save you time and money. Upgraded mounts reduce the chances that your headers will rub on the frame of your Mustang, something that generally happens with lower quality headers. If your headers contact your Mustangs frame, engine vibrations will be passed into the chassis, causing unpleasant noise, vibration, and harshness. Frame contact can also trigger false knock, causing your PCM to pull timing, reducing the output of your engine.

Replacing motor mounts can be either a great idea or a downgrade. If the owner is after performance, poly mounts are the way to go. The stronger connection, consistent firmness, and better handling qualities can be greatly improved with poly mounts. However, if the Mustang is primarily for cruising the streets or just being comfortable, rubber mounts (even the stock ones) can perform that function well. Stock ones will feel smoother while poly mounts will feel more connected to the car while improving handling and increasing vibration. In the end, the choice is up to the driver, performance based or comfort based.

Lowered engine mounts are also required on the S550 (2015-current) Mustangs when installing upgraded intake manifolds like the Cobra Jet or Boss 302 intakes. Due to the tight clearance between the hood and engine, these taller intake manifolds either require a dropped engine mount, cut hood supports, or both. Dropping a set of lowered mounts in your Mustang will make it less likely that you’ll have to break out the cut off wheel when installing your new intake manifold.