I’m sure you could use a little time off and would like to come to colorful Colorado and help me with this little effort
I’ve also been looking at this double coverage Mid America Motorworks offering:
Scott
I'd come over to colorful Colorado, I spent almost 3 years there racing motorcycles, er, going to collage.
The vettemod kit is worthless, no foil.
The other 2 kits look pretty good.
One of my jobs at Ingersoll-Rand was "sound control engineer" trying to quiet down construction equipment at a time when no one else was doing it, - not easy.
I did use close cell foam with doublesided foil in the engine compartments, it worked well on higher frequencies, so I like these kits for some of the road/wind noise.
I think you have to separate exhaust noise/resonance from the road noise. Exhaust is at lower frequencies and an exhaust system also vibrates thus the resonance. And I agree that the rear of a C4 underneath the car has a lot of spaces that will act like a base speaker cabinet. So, if you want to keep the current exhaust system, the only thing you can do is change the mass of some of those panels so that they vibrate at a different frequency - the bed liner Andy mentioned or maybe undercoating. Or change to Corsa, their engineers must a boatload of time working on the resonance thing.
The exhaust thing would take a lot of experimenting.
Your custom rear valance may be contributing somewhat, it would be interesting to pull it off and see if anything chances.
Just let know when you’re arriving I’ll get the room ready . Things probably haven’t changed all that much, although there are a few more brew houses to explore. Where’d you go, Ft. Collins, Boulder?
I know the exhaust is a major noise contributor from an idle to cruising where resonance is very apparent. In all likelihood I’ll wind up with the Corsa, right now it has a nasty snap as you can imagine. The other noise generator is the fuel pump; it kinda adds that piercing dentist’s chair drill sound to the road and exhaust noises.
I’m planning on taking a good look at the rear valance area where some type of undercoating may be desirable.
My overall goals are fairly straight forward. Right now the noise factor inside the car is high and I want to bring it down to a more reasonable level. I’d like to be able to carry on a conversation and even hear the radio . According to the write-up on one of the kits I’m considering; it knocked nearly 12 decibels off the interior sound level, I believe that would be noticeable.
. Things probably haven’t changed all that much, although there are a few more brew houses 
to explore. Where’d you go, Ft. Collins, Boulder?
. According to the write-up on one of the kits I’m considering; it knocked nearly 12 decibels off the interior sound level, I believe that would be noticeable.
