This serves 2 purposes,

One to show how bad that Vararam aircleaner setup is and how engine functions when adding mods and not custom tuning for it.

We have shown several times with many Corvettes using this Vararam and as seen here how flakey the airflow is to engine RPM/load

Notice as there is more engine load as to the amount of air in grams per cylinder how the fuel trims are all over the map.
For good performance the fuel trims should be a fairly smooth line rather then the sick snake we see with the LTFTs.

Larger the positive values the leaner it is and the lower the negative values the richer it is.



On the left we see how the engine was doing with owner adding bit larger injectors, headers and that Vararam.
On right is after we custom tuned out all the ills

Notice the maximum airflow brought into engine was only 535 CFM, had low WOT timing, lots of knock and no real performance gains seen.

Once tuned you see the WOT timing where it really belongs, no knock, fuel trims now perfect, engine pulling better as seen with CFM increase and of course now lots more HP and Tq



Unless people learn how to use a OBD-II scanner and analyze that data and they cannot see a tune in their hand they have no clue really how well or bad mods are and their reaction to engine performance.