The 'Stealth' Z - Part 8

by Steve 'Stealth' Webb

Steve Webb Missing out on your new car stereo system due to road noise? Do you find yourself yelling to your passenger to carry on normal conversations? Well, hereís some good tips and ideas for a whisper quiet interior.

In the (early) Z-Car, there was pretty much nothing installed in the way of sound insulation. This is great for weight savings, but tough on the ears. Just to give you an idea, the first generation 300ZX in 1984 had 75 lbs to 100 lbs of sound insulation in it.

To start with, the easiest, cheapest single most effective noise-control step is to make sure the weatherstripping around the door is in good shape and is sealing properly. This is especially important in a Z, as the window frame is only inches from your ear. Permatex brand Black Rubber Sealant RS-9 works exceptionally well for repairing torn and aging weatherstripping. New door seals from Nissan are very expensive and typically seem to already be 15 or 20 years old (mine started tearing and coming apart only months after being installed - and the car is always garaged). The window channel felt can also be purchased through Nissan and will make a BIG difference in window sealing, and will keep it from rattling to boot.

The next step is to make sure all the holes in the firewall are sealed with a grommet or closed up with a plug or silicone sealant. In addition to noise reduction, this will also do a lot towards keeping exhaust fumes out of the passenger compartment.

Now for the sound insulation. There are three basic methods of noise reduction: damping, absorption, and barrier.

Composite materials are a combination of barrier, damning and absorption materials bonded together to achieve properties one material alone cannot provide. This is probably the most effective single noise reduction product. Of course it is also the most expensive.

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