What
the Turbocharger does for the Merkur:
The power that an engine generates in proportional
to the air throughput. Because air throughput is, in turn, proportional
to air density, the power of an engine with constant displacement and engine
speed can be increased by precompression of the air before it enters the
cylinders. The supercharging ratio indicates the increase in density
compared to a normally aspirated engine. The supercharging ratio
depends on the equipment type used (in this case, a turbocharger) and is
the greatest given a specific increase in pressure when the temperature
of the compressed air is not increased or is returned to its initial value
by intercooling.In gasoline engines, the supercharging ratio is limited
by the knocking tendency of the engine. In order to minimize this
problem, turbocharged engines customarily use lower compression ratios
than normally aspirated engines.
Intercooling,
or charge air cooling, performs two major functions:
1.
The increase in density as the temperature drops can be converted into increased
performance.
2.
The lower temperature tends to raise the knock limit of the engine. Other
benefits of the lower charge air temperature are lower exhaust gas temperatures,
reduced NOx content, and a reduction in the thermal load on the engine.
Intercooler
basics:
With an intercooler, the
hot, pressurized air is passed through a heat exchanger and cooled.
This results in cooler, denser air. This helps because you can run
higher boost before encountering detonation with the cooler air.
The air is also denser which means that the air packed into the cylinder
is more dense than it would be at the same pressure and a higher temperature.
The result is that you can run higher boost
before encountering detonation. You will have more power and the
engine will run cooler all the time since air is being removed from the
system. Also since it mainly is cooling when the engine is under
boost, it really doesn't do much when you are going down the highway, meaning
that it will not significantly affect cruising mileage. The only
real downside that I experienced was the added cost/ complexity that the
intercooler adds. This is probably the main reason that some kind
of intercooler wasn't original equipment on the Merkurs.