Why USA made diesels are so darn loud?

[vahe]

A litte OT. but I have always wondered why American made diesels, the pick up trucks, are so loud and noisy. The Europiean diesels are getting more refined with every new model, the MB CDI sounds almost like a gasser, it is so quiet.
Guy living across the street from us has a 3/4 ton diesel pick up, we always wake up when he cranks that car in early mornings, it sounds much like a dump truck enloading a full load of gravel across the street.

Vahe
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