sound mat/pad

[smooth_eddy]

My 74 914 has a 3/8" thick dynamat on the engine compartment firewall. Inside the car seems to be noisy compared to other 914's I have driven. Should I supplement the dynamat with the stock sound mat/pad? Is it worth the effort (and $100)? Or will the stock mat just peel loose in time like they all tend to do?

[sean_V8_914]

is your rear window properly sealed ? is the stock back pad in place? These 2 items make a significant difference

[914GT]

I think Sean's right that noise comes through the window, so at least make sure you have a good seal around it. But if you want the interior to sound nothing like a stock 914 and more like a new car there are three things that make a big difference. First, line the floor and inside the doors with Dynamat or similar sound dampening sheet. Second, over the top of the Dynamat on the floor and behind the seats on the firewall up to the window lay down a 1/2" thick layer of Armaflex high density foam insulation (from HVAC equipment supplier). The last thing is good carpet, and fabric seats and door panels to really deaden the sound. All that vinyl reflects sound around inside the car.

[Lyle]

In addition to the upgrades already mentioned by others, here is one more for you to consider:Remove your Targa roof and lay it on the floor upside down You will notice that in the area located directly above your roll bar, there is a roof cavity that runs the width of the roof by roughly five inches front to back. This air space is one of the ways noise gets conducted into your car. If you glue a piece of sound absorbing black foam rubber into this cavity, you will be blocking one of the paths that engine noise can take. I've now made this upgrade to three cars and it reduced the noise level on all of them. This idea is not mine nor is it anything new. Chuck Stoddard mentions it in a Panorama article years ago.

Lyle

[SGB]

Excellent suggestions. I've been wanting to restore a little civility to the 914. Another place I noticed that conducts a lot of noise is the narrow panal between the back window and the engine cover grid. I put a piece of dynamat like material there and it reduced the vibration of that panal a lot.

[sean_V8_914]

thanks for teh ideas guys.