H1 vs HMMWV noise?

[erasedhammer]

The GEP engines are quieter because of the thicker block and fire deck. That combined with the insulation of a h1 makes for a quieter ride.
Ive had two sound readings at 65, 6.2 with 4l80 was 117 db next to the drivers side of the doghouse.
GEP 6.5 turbo and 4l80 at 65 was 90 db at the doghouse.
I added some of my own insulation though.

 

[1 Patriot-of-many]

I replaced my 6.2 with a GEP6.5 NA. IMHO there is a big difference in noise. Mine too is louder when cold. Most likely fuel not burning completely from lack of heat. But once it gets hot it is smoother and quieter than my GM6.5 in my CUCV. Don't get me wrong. It isn't close to gasoline quiet. But I am happy with it. You can get sound insulation that you cut to fit from places like summit racing. You should be able to make a difference with products like that.

Cold advance

 

[ltrpd]

I have a 2001 h1 wagon, I used dynamat on both doghouse covers. I dynamated the entire interior and also used dynapad. Reduced engine and road noise significantly. It was costly but I feel well worth it.