On Sun, 24 Jun 2012 18:15:11 +0100, "Arfa Daily"
wrote:

OK. So I was watching an episode of the U.S. documentary series "Undercover
Stings" a couple of nights ago, and the camera focused briefly on a post by
the side of the road. It had two square signs on it. The upper green one
said "Starke City Limit" which I understood, but the one below it - white
background, black lettering, black line all around the edge, said "Engine
Braking Prohibited". What does this mean ? I understand what engine braking
is - here in the UK at least - but does it mean something different your
side of the pond, and why would it be prohibited anywhere ?

Arfa
If you don't want to google "Jake Brake" then I'll explain a little.
The exhaust valve is held open after the air is compressed in the
cylinder. A similar device used to be available, and probably still
is, for use on 2 stroke engine powered dirt bikes and they are both
compression release devices. So most of the energy used to compress
the air is lost before it can cause the piston to rebound. The reason
they aren't allowed in city limits is because they are so loud.
Eric