I did some testing of the Roto-Fab vs. stock airbox with a Green Filter. Stephen Fitzgerald Selden has been a proponent of the stock airbox for road course duty for a while. I swapped the Roto-Fab that was on the car and put the stocker back on. The PDR captures Ambient Air Temp and IAT, but doesn't get MAT. You can get all this data in Pi Toolbox with a little work.
Results:
- Stocker +10 HP on Average
- Roto-Fab +13 F hotter IAT Average
- Boost was .7 psi higher with the Roto-Fab, but power was lower due to air density and likely less timing
- Ambient temps were close +/-2 degrees on the testing days
- Verdict: keeping the stock intake on with the rain deflector removed from the grille