Intake air flow modification

[zpiloto]

Wanted to see how intake air would affect FE with increased airflow and then with a restricted airflow. Removed the original 18” airduct that went from the air box to the forward corner of the engine compartment and replaced it with a 4” long piece of 2” diameter PVC that is directed towards the exhaust manifold. Reset the ECU and did runs with car configured with normal, 2” hose, and restrictor plate on a 41 mile test loop. The restrictor plate was made buy covering 2” hose with cardboard with a 1”x1”hole cut in the center. Each mod showed an improvement. With the restrictor there was a slight decrease in acceleration but good drivability. Max RPM was 3575 and Max speed was 60 MPH.
The restricted airflow shows promise but I forgot to reset the ECU for that run. During the run with the restricted airflow when I would shift into neutral to coast the idle RPM would only drop to around 1300 until the car would come to a stop then drop down to it’s normal 650 RPM. Towards the end of the run the idle was dropping to 1000 RPM so I think that it will eventually get back to its 700-800 RPM range which will save on fuel. Scan gauge results below.

Conditions: Beginning of runs calm winds 76
End of runs calm winds 70

Normal 36.4 MPG
40.0 MPH Avg

2’ Hose 37.0 MPG
38 MPH Avg

Restricted 37.3 MPG
39.0 MPH Avg