For ACC brand passenger and cargo area carpet, is the $100 mass backing option worth it over the standard poly backing? Not so concerned about sound deadening or insulation, but more about fit and finish.

 

Not sure if this helps or not, but I took out my padding under the carpet.
I lost about 14 lbs.
I haven't driven the car yet to see if it is louder or not.
But the fit was fine without it!

Another MB car!
Where you from?

 

I went with the Mass Backing,but that's because that's what the car came with.

 

I had the poly backing on the first carpet I bought…it bunched up and never laid flat. It was cheaper and I found out why right after the install.

The mass backing makes it a pain to install, but once it's in it lays flat with no wrinkles. If you're concerned with fit and finish….Just my opinion.

 

Was the poly backed carpet you had ACC brand?

 

Yes….

 

I have used both ACC carpets with mass backing and without, with the mass backing it weights a lot more than without.

If done on a warm day, let lay in the sun the time it takes to remove tho old carpet, both fit perfect. Finish is the same.

With the non mass backing carped I insulated the body with 2 layers of 4mm PE Bubble Aluminum Foil, honestly I prefer the sound in the vehicle better then in the car with the mass backing carpet.
The PE Bubble Aluminium Foil is ultra light, I also noticed that it isolates the heat from the catalytic converter and the transmission better then the Mass Backing.

 

With 2 layers of bubble foil does the carpet feel soft? How thick is the mass backing compared to two layers of the bubble foil? Did you glue down the bubble foil?

 

The PE boubble foil I used, not sure it is actually called that way but it is basically a foil of aluminium glued to a sheet of Polystyrene foam.

To install the Aluminium/Polystyrene isolation, I used some double sided tape (used for fixing carpets to the floor), it is not necessary to cover the whole body with it.
Between the layer of isolation and the "standard" carpet, nothing.

The mass backing is a layer of around 4 mm Linoleum type material added on the back of the "standard" carpet.

Impossible to tell the 2 appart optically and physically, if you do not know what is under it. However you can tell the difference if you bang for exemple the knee against it.

For the carpet material door inserts if you have any, you must use carpet without mass backing.