[Gunter]

Quote by wwest:

"This is nothing less than PURE BS"

Why divert engine cooling airflow in favor of cooling the exhaust manifold rather that having FULL engine cooling airflow AND cooling the heat exchangers in the same process...?

Grady never said to just cool the exhaust manifold without full airflow for the engine.

Consider more carefully before calling the input from a very experienced and helpful contributor pure BS.

It goes without saying that the cylinders need aircooling before anything else and the design by Porsche was always to have full airflow for the engine.

The auxiliary blower is not absolutely necessary but was added to supply extra heat for the cabin at idle, AFAIK. Main airflow has always come from the big fan supplying aircooling whether the flappers are open or closed.

So, whether using the air for the cabin or just have it diverted into the void, the design calls for full airflow through the HE's either way and I'm sure Grady knows that.

If the extra blower is removed, a block-off plate is used and a hose is re-routed to ensure that full airflow is maintained as intended by design.

When adding SSI's, the auxiliary fan and hoses on top of the engine are removed and different plates left and right of the fan are installed with short new hoses to the SSI HE's.
That's "back-dating" and actually gives more heat as experienced by this old ME.