On Mon, 22 Aug 2005 14:39:32 GMT, john smith wrote:

snip

An intercooler is a radiator that cools a gas (air) instead of a liquid.
When air is compressed (what a turbocharger does) it heats up. When a
gas is heated it wants to expand (return to an uncompressed state), so
you place an intercooler (or two) inline following the turbocharger and
before the engine air intake, to cool the heated, compressed air before
it enters the engine, providing cooler, more dense air to the engine.
Cooler dense air can absorb more heat than hotter dense air and provide
greater expansion and therefore more power.

Technically, an intercooler is a "radiator" placed between a
exhaust-driven turbine compressor and a mechanically-driven turbine
compressor (a la B-17). Your description of an aftercooler is spot-on.

You may not be familiar with the Turbo Lance/'Toga "intercooler"
installation. It is a relatively inefficient aftercooler installation
that has other very important benefits.

It changes the existing lower cowl design from a single common air
inlet which is shared between updraft cylinder cooling, induction air
supply, and oil cooling air cupply. The new lower cowl has separate
inlets for updraft cylinder cooling, induction air, and oil cooling,
as well as the aftercooler inlet.

Unfortunately, the outlet of the aftercooler heat exchanger is
exhausted into the pressure area for the updraft cylinder cooling.

The installation will drop operating CHT by approximately 40-60
degrees F, and operating oil temp by 20-40 degrees. Considering that
CHT can run 450 F and oil temp 220+F this is a very good thing.

I honestly cannot recall the typical induction air temp drop, but the
overall package works quite well. IMHO this is as much a result of
improved engine/oil cooling air flow as actual induction air cooling.

Personally, I would not consider operating a Turbo 'Toga/Lance without
this modification.

Regards;

TC