Mk7 Intake Manifold - Closed Flaps

Mk7 Intake Manifold Flow Test

Background:

Curious about how well balanced the flow is across the intake manifold runners led to performing this test. A Mk7 GTI intake manifold is the subject of this flow test.

Mk7 Intake Manifold Flow Test Flaps Open
IM Flow Test – Flaps Open

Test Procedure:

The GTI intake manifold is attached to the flow bench using an adapter that supports exhausting airflow from the bench through the intake manifold throttle body opening.

Mk7 Intake Manifold Flow Test Setup
Intake Manifold Flow Test Setup

First air is exhausted out of the intake manifold with all runners open. Then the port flaps are closed to assess the affect on airflow.

Next each runner is flow tested individually. To do this one runner is left open and the other three are blocked with a piece of foam.

Intake Manifold Runner Foam Plug
IM Runner Foam Plug

The foam block is inserted into the runner to sufficient depth to keep from being blown out during the flow test.

Intake Manifold Runner Foam Plug
Intake Manifold Runner Foam Plug

Flow testing is conducted at 16″ of H2O.

Test Results:

With all runners open the Mk7 GTI intake flows 458 CFM @ 16″ of H2O. With the intake flaps closed the manifold flows 326 CFM @ 16″ of H2O.

Mk7 Intake Manifold - Closed Flaps
Mk7 Intake Manifold – Closed Flaps

These results are shown on the chart:

Mk7 Intake Manifold Flap Position Flow Test
Flap Position Flow Test

The blocked runner setup is shown below:

Mk7 Individual Runner Flow Test
Individual Runner Flow Test

Flow readings for each runner are shown on the chart:

Mk7 Intake Manifold All Runner Flow Comparison
All Runner Flow Comparison

Conclusion:

The maximum flow difference is 4% with a measurement margin error of approximately 1%.

Uniformity of airflow between the runners seems good (emphasizing this is an opinion).