Showcase Hummer H1 Part 3: Sound Insulation and Anti-drumming

How to soundproof a bonnet
Vibrations and resonances from the engine cause noise nuisance in a vehicle. Only insulate a bonnet when the bonnet does not exceed the temperature of the products mentioned on this page! For sound absorbing products about 80 °C and for anti-drumming products, applied upside down under the bonnet, about 60 °C. If you are not sure about the temperatures in the engine bay, only use sound absorbing products. Use bitumen damping sheets inside the cabin to reduce eninge noise. See the page "Vehicle insulation" for the right solution.

Soundproofing the bonnet with deadener
To reduce vibration in the bonnet you can use bitumen damping sheets, Vibraflex Normal. As mentioned, only used damping sheets if the temperature does not exceed about 60 °C. In large vehicles with sufficent space between the engine and the bonnet this should not have to be a problem. Clean the surface of the bonnet thoroughly and only insulate the flat parts of the bonnet. Use the pressure roller to make sure the Vibraflex damping sheets are applied as they should.

Soundproofing the bonnet with noise absorbing
After the anti-drumming of the bonnet a layer of sound absorbing material is required, reducing the amount of engine noise that can radiate around the vehicle. Which product you can use depends on the temperature in the engine bay:

• Acousticcell PU:
  We recommend Acousticcell 19 mm thick for bonnets up to 80 °C. The thickness of 19 mm is easy to cut, and in most cases this noise absorption foam won't touch the engine. Measure twice, cut once! This insulation product is provided with an oil, dirt, and moisture proof top layer. Resistant against temperatures up to 80 °C.
• Merfocell FC: 
  This is an absorbing foam provided with a glass fiber cloth top layer. Products with a fiber cloth top layer can only be applied on flat surfaces. The product is resistant against temperatures up to max. 110 °C. Also self-adhesive, easy to cut and protective top layer provides protection against oil and dirt. Not sure what to use? Just let us know, we are happy to helpo out!

More guides about vehicle insulation
On our page with solutions regarding vehicle insulation you will find the most common problem areas. Additional tips pages and guides about various types of vehicles you can find here:

• Campe vans & Motorhomes
• Land Rover
• Mercedes 508 & 608 (Hanomag)
  

Questions?
Do you have questions about how to insulate a car or camper van? Please feel free to contact us, we will be happy to answer your question as soon as possible.