Hi Paul and group,

A question regarding kinetic energy.  How do one measure the level of
kinetic energy at the exhaust.  An instrument placed at the the two or
three exhaust exit.  Is it just that simple?

Marc J.

Kinetic energy is just the blast of exhaust gas coming out of the engine.

You can get one of these wind speed meters and hold it near the
end of the exhaust pipe. Put the car on a chassis dyno and run it up
to full power. Note the airspeed of the exhaust. That would be the airspeed
coming out of an annular shaped orifice in front of a turbine with the
same cross sectional area as the exhaust pipe tip.

If you consider the turbine blade a wing
with a lift coef. of one.. the force on the blade would be .0026 times
the relative air speed squared in MPH times the area of the
blade in square feet.

The torque is the number of blades times the force on each blade
times the radius of the blade. Good turbine blades can have lift
coef. up to two. Max turbine power is generated when
the tangential velocity of the blade is about half the max exhaust
gas airspeed.

The gas speed out of the exhaust pipe tip will be reduced by
the heat loss in the muffler and the rest of the exhaust system.