Car Floor Sound Deadening

The exhaust system combines the exhaust gases flowing from the cylinders and cleans them of pollutants. It also reduces exhaust noise and directs the cleaned exhaust gases from the vehicle interior to the outside.


Depending on the engine, the exhaust system can consist of one or two lines. The flow resistance should be selected so that the engine’s performance is affected as little as possible by the exhaust backpressure. For the exhaust system to perform its tasks optimally, it must be considered and developed as a whole. In other words, designers must match its components to each other in a way that is specific to the engine and the vehicle.


Every internal combustion engine generates a so-called “noise” due to the pulsating gas output from the cylinders generates what is known as “exhaust noise. This is damped by reducing the sound energy of the exhaust gas stream. There are two ways of doing this: absorption and reflection of the sound. These processes mainly take place in a muffler. But resonators and exhaust gas flaps also contain sound-absorbing and sound-modifying elements that can be used to eliminate particularly disturbing frequency components in the muzzle noise. Catalytic converters also have a sound-absorbing effect. However, in addition to the noise from the engine, the exhaust system itself also generates noise through natural frequencies and vibrations. These are introduced into the bodywork. It is therefore important that the entire system is carefully tuned. This includes the design and positioning of the individual elements of the exhaust system and their elastic mountings.

Other functions of the exhaust system

In addition to its sound-absorbing tasks, the exhaust system is also exposed to extreme influences: The fuel-air mixture in the cylinders is abruptly heated to up to 2,400 °C. This causes it to expand. As a result, it expands many times over and shoots into the exhaust system at supersonic speed. This produces explosion-like banging noises which have to be reduced by 50 dB(A) from the engine exhaust valve to the end of the exhaust system. In addition to these temperature and pressure loads, the exhaust system must dampen vibrations emanating from the engine and the body, as well as vibrations and impacts from the road. Furthermore, the exhaust system must withstand corrosion attacks from internal and external sources. This includes hot gas, acids, spray and salt water. In addition, the exhaust system must be resistant to the danger posed by poisoning of the catalytic converter by sulfur or lead in the adhesive.

Structure of the exhaust system

A modern exhaust system differs considerably from the plain models of the past. In newer passenger cars, it consists of the following components:

  • front system with exhaust manifold
  • a cleaning system
  • connecting pipes
  • rear system with the silencer system and pipes

The entire system is connected to the vehicle floor with elastic suspension elements. The number of catalytic converters and silencers depends on the type and power of the engine and the targeted emission levels.

Oscillation damper and end-coupling elements

In V-engines, each of the two cylinder banks has its own exhaust tract. These either remain separate up to the tailpipes or are combined beforehand. The latter is done in a common rear muffler. In modern exhaust systems, vibration dampers and decoupling elements are installed. These prevent violent vibrations of the tailpipe, which in the worst case would lead to breakage. They also prevent large excursions of the exhaust system and minor vibrations that would be introduced into the exhaust system by the engine and arrive in the interior as sound impulses. Vibration absorbers and decoupling elements thus increase driving comfort and the service life of the exhaust system.

Sound insulation in cars, vehicles and vehicle construction

Loud roaring, hissing and vibrating. Noise in cars, mobile homes, classic cars, commercial vehicles or agricultural machinery can not only be annoying in the long run, but can even pose a health risk. But why is it often so loud, especially in older cars or heavy vehicles, and what can be done about it?

What are the causes of noise in vehicles?

Ambient noise, engine noise or the rolling noise of the tires are partly responsible for an increasing noise level in the vehicle. To contain this noise, vehicle manufacturers invest many resources in sound insulation measures and new technologies for noise suppression. However, especially in older vehicles or large commercial vehicles, sound insulation is often inadequate. The reason for this usually lies in the design of the vehicle itself. The roar of the engine generates vibrations that are transmitted to the large sheet metal structures (e.g., doors, floor panel, roof) of the body and cause them to vibrate. If these structural elements are not adequately damped, the vibrations travel through the vehicle as “structure-borne noise” and are then emitted again to the surroundings as a loud roar. The large sheet metal structures on vehicles, such as doors, roof and floor panels, start to vibrate during operation and transmit structure-borne noise. This is later emitted back into the environment as airborne sound, and noise is generated.

Why is sound insulation so important in vehicle construction and bodywork?

Persistent noise in a vehicle not only impairs the quality of life, but also the concentration and performance of the driver. In an emergency, this can become a safety risk. A continuous noise level above 85 dB increases stress, the risk of cardiovascular diseases and can lead to permanent damage to hearing. Noise insulation in commercial vehicles, agricultural or forestry machinery can also be relevant in terms of occupational health and safety and to prevent damage to health. Sound insulation in the vehicle helps to reduce noise. Especially people who spend a lot of time in the car or vehicle should pay attention to sufficient noise insulation to protect their health.

What are the options for retrofit soundproofing in the car?

First of all, it is important to locate the source of the noise. In this way, individual components such as the floor panel or separate areas such as the engine compartment can be specifically soundproofed.

Sound insulation in the engine compartment

Sound insulation panels with membrane absorbers are the first choice for sound insulation in the engine compartment. The sound-permeable special film on the surface protects the absorbers from spray liquids and oils. On the rear side, the panels can also be selected with a self-adhesive finish and thus be easily glued into the engine hood. To perfectly cover the panel transitions between the elements, we also recommend our aluminum tape. Please note: aixFOAM products for sound insulation in vehicles comply with the fire class FMVSS 302 (DIN 75200), which is common in automotive engineering. However, sufficient distance to the engine should be kept. In the area of the exhaust and the manifold, the installation of a sound insulation panel in the car is not recommended.

Anti-drumming of the car body and floor panel

To minimize material oscillations and vibrations of the sheet metal surfaces, it is necessary to reinforce the material so that it does not vibrate so easily. The aixFOAM anti-drumming mat made of acoustic heavy foil is particularly suitable for this requirement. It has a high intrinsic weight, is extremely pliable and flexible. The heavy foil is also equipped with a practical self-adhesive surface as standard, so that it can be bonded quickly and easily to the inside of the car body. In addition, the floor panel can be insulated with our acoustic heavy foam sound insulation panels.

Sound insulation for classic cars

Our aixFOAM acoustic products for floor insulation are also recommended for sound insulation in classic cars. The acoustic mats can be cut to size and laid flexibly and ensure more quiet and comfort in the vehicle. Driving pleasure without noise: Sound insulation panels deaden the car body and isolate noise sources in the car. As a result, they bring peace and quiet to older vehicles and classic cars.

How does sound insulation succeed in other vehicles?

Below we have gathered some information and tips on sound insulation in special vehicles and machines.

Sound insulation for mobile homes and caravans

In addition to vibration noise and engine roar, insulation in a caravan or motor home also keeps out ambient noise from outside. Rain pattering on the roof, hail or the noises of the neighbors on the campsite can steal the last nerve with poor sound insulation and spoil the vacation mood. With our self-adhesive sound absorbers, you can optimally soundproof the roof of your rolling home quickly and easily. For this purpose, we also recommend absorbers with a high weight per unit area, such as our acoustic heavy foam, to stop the transmission of structure-borne sound through the walls or roof. For maximum insulating effect, we recommend additionally laminating the heavy foam with acoustic heavy foil. You can easily select this option in the product configurator. Sound insulation in motorhomes, caravans or trailers helps isolate ambient noise – for a quiet and relaxing vacation.

Sound insulation for trucks and special vehicles

To deaden the cab, we recommend acoustic heavy foil to reinforce the cab material to stop vibration and transmission of structure-borne noise. For sound insulation in the interior of the driver’s cab, aixFOAM sound absorbers with acoustic felt lamination or sound insulation mats with a perforated artificial leather surface are suitable. They are visually appealing, highly effective in sound absorption and washable. Since the driver’s cab is often not only the workplace but also a living space on wheels, these absorbers are predestined for sound insulation in trucks. Our sound absorbers are also suitable for sound insulation in special vehicle construction, sound insulation in trailer construction, sound insulation in construction machinery or buses, and insulation in rail vehicle construction. For deadening, the same procedure is advisable as for deadening the bodywork of a car. More peace and quiet on the road: The right sound insulation for trucks and special vehicles isolates noise from the vehicle and its surroundings. This relieves the strain on professional drivers in their day-to-day work.

Sound insulation for agricultural machinery, forestry machinery and commercial vehicles

They are large, have a large number of vibrating attachments and powerful engines and transmissions: it’s no wonder that tractors and agricultural machinery generate considerable noise and vibrations. In addition to the classic acoustic heavy foil for deadening the bodywork, our sound insulation mats with surface lamination are particularly suitable for sound insulation of agricultural or forestry machinery and vehicles. The aluminum membrane is liquid-repellent, oil-resistant and insensitive to the high dirt load in the agricultural sector or forestry. For less noise at work, retrofitting sound insulation to agricultural and forestry machinery makes sense. aixFOAM sound absorbers for vehicle construction are available with special surface laminations and are thus resistant to soiling.

Fire protection and sound insulation in vehicle construction – fire protection class FMVSS 302 (DIN 75200)

Our sound absorbers for technical sound insulation are available in accordance with fire class FMVSS 302 (DIN 75200), which is common in automotive engineering and vehicle construction. Nevertheless, when selecting your sound insulation panels, please note the technical data on temperature resistance, which we have compiled for you on the article pages of the respective products. For detailed information, we will also be happy to send you the data sheets of our absorbers on request. Simply contact our customer service. To keep the safety risk low when soundproofing vehicles, sufficient distance to the engine and other components with high heat generation, such as manifolds or exhaust, should be maintained.

Why is aixFOAM sound insulation the best choice for sound insulation in vehicle construction?

Through 60 years of experience and continuous optimization of our high-quality acoustic materials, we have succeeded in developing flexible and robust sound insulation elements with high absorption values. As a modern manufacturing company, we are not only able to offer you standardized absorbers in panel form, but can also produce individual contours for precisely fitting installation in vehicles and engines. Simply discuss your wishes with our service team. Your individually manufactured aixFOAM acoustic kit for sound insulation in vehicle construction: With the latest, high-precision CNC technology, we can produce customized sound insulation for your vehicles and engines. aixFOAM sound absorbers reduce noise and structure-borne sound and are available in various fire protection classes and material thicknesses. Choose your favorite from several surface profiles. Various surface laminations make aixFOAM sound insulation panels resistant to liquids and dirt, and the practical self-adhesive finish facilitates installation even in difficult places. Manufacturing standardized or customized Surfaces Profiles to choose from Heights variously selectable Mounting several options Fire protection various classes Protection against dirt & liquids.

Now it’s your turn: get the right sound insulation for your vehicle!

Choose now from our aixFOAM products for vehicle construction your suitable sound insulation or use our free consulting service. Our expert planners will support you in your projects and help you find the optimal solution for your requirements. The aixFOAM expert planners are available to you by phone or e-mail. Free consultation Here you can find the right sound insulation for your application in vehicle construction. To the products Car Floor Sound Deadening.

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