I've been doing a ton of research on other drivers experiences and methods using sound deadening. I want to take a cost effective approach but splurge on some of the obvious areas such as under the hood and around the drive train tunnel and firewall.

I'm going to start at the biggest source of noise. that 4.5 V8. I bought Dynamat Hoodliner. It's 3/4 thick and I've been reading some really good success stories when it comes to hushing noise. Plus it will be the easiest noise suppressor to install. I'll try to test noise suppression using my iphone DB meter app. Relax, I know it's not super scientific but i'll keep the environmental factors equal to try and A/B test as clean as possible. It's better than no measurement at all.

I will use the leftover material to insulate the transmission tunnel, then layer it with MLV acoustic vinyl. I'll probably sandwich a layer of closed cell foam then put another MLV layer to make sure the tunnel is soundproof. I will do the same + dynamat with the rear hat shelf because i know the trunk is a big noise source.

From my research, from a weight saving and cost savings standpoint, I don't have to completely cover every square inch to metal with dynamat. I can cut it into squares and place it in key areas were the metal resonates. I can see there is some factory deadening so i can supplement around that. I don't have a kickin stereo anyway, so i'm not worried about subwoofer vibrations

Behind the rear seat will use more dynamat over the wheel wells and do the same layering with ccf and MLV. My 300D has 2 layers of 1/2 thick acoustic batting. I got the 2nd layer from another mercedes at a junk yard for super cheap, so i may just pick up more of that stuff since it's easy to get.

I'm going to do 1 major area at a time, and I'll do my best to measure my results with the DB meter so I can share with you if I had success, or just wasted my time. Ultimately what matters is how it sounds to me. I've got a really good ear and I get really annoyed at road noise, so I'll know if my efforts made a difference regardless of what the db meter says.


This guy had an interesting write-up of his sound deadening efforts. Cool Read overall.
Infiniti qx70rs - 1000+ hp luxury hybrid suv project


WISH ME LUCK!!!!

If there are any w108 owners on this forum that live in Los Angeles, i'd love to go for a ride in your car. I've only driven in MY w108 so I have no comparison of how quiet/smooth a w108 should be.