Cabin Heat Modification

[wwest]

PROS:

1. Constant cabin heating level, no variation with RPM.
2. Additional engine cooling airflow.
3. Additional engine lid condenser cooling.

CONS:

1. No "parasitic" exhaust manifold cooling.

[Slanski62]

Which part is this and what years does it apply to?

[Bergo]

so, it's a plastic plenum that works as a block off plate, but lets you keep backdated heat?

[wwest]

Heat air flow comes ONLY from the 12v blower.

[911pcars]

Originally Posted by wwest

Heat air flow comes ONLY from the 12v blower.

Hot air from the heat exchanger now has two exit paths, the heater control valve and these holes. What prevents the electric fan from forcing heated air through these holes and into the engine compartment?

Sherwood

[wwest]

There is a metal blocking plate (excessive RTV sealant) to prevent flow to/from the engine, and the holes are on the suction side of the cabin heat blower.

[wwest]

Results, 800 RPM:

FPM =125 CFM = 175.

With Cabin heat blower on:

FPM = 225 CFM = 315.

Air intake 1.4 sq. ft.

Extra cooling for the engine lid condenser.