Testing

MAF Screen Flow Test

The Test:

This investigation was done to get some insight into the amount of obstruction the screening at the entrance to the MAF housing causes.

I had the ends from a stock MAF housing which I attached directly to the flowbench to measure the airflow through.

maf_housing_ends

Results:

Running the test depression up to 10″ of H2O the results were:

screened_maf_airflow The setup for the test was not ideal, just having the ends of the MAF housings and mounting them directly to the bench which meant the sharp edges were present for air to flow around as the air was drawn through the housing ends.  But, as a check to see approximately how much obstruction the screen causes I believe this setup was adequate.

The removal of the screen under the conditions that I tested showed roughly a 5% increase in airflow at the same test depression.

Tuning

Nef4 Relogged

I added a few suggested variable for logging to try and determine why the boost profile shows boost levels rising with rpm where the LDRXN defines a profile that has boost decreasing with increasing rpm.

Nef4 variables

The entire set of charts is shown here:

Nef4 Relogged

Turbo Selection, Turbocharger

Turbocharger Selection Big Picture

This chart of torque from a number of dyno’s illustrates how different size turbochargers will delivery a different driving experience.

The car setups can differ greatly, having a significant affect on the outcome, but the general idea is to find a median value from a number of cars to help illustrate how a particular type of turbocharger might perform on a typical S4.

Turbocharger Torque Comparison
Torque Comparison

Next: New option from SRM

Audi B5 S4 Information and Testing