So are you saying that we would be just as well off with a Stage 0.5, keeping the factory filter and fitting straight through pipes?
Pretty much...but the factory filter cover seems to be pretty restrictive so some modification would be a reasonable idea to let some more air get to the outside of the filter.
Agreed.
Preferring the aesthetics of the factory filter, I've more than doubled the opening of the lower area of the filter cover, as well as cut down the upper arc of the alloy backing plate to exactly match the outer diameter of the filter element (which considerably opens up the top side of the filter). Theoretically it is still more "shrouded" than the open muscle element, but swapping from the muscle filter to the modified factory unit is undetectable to me from a seat of the pants perspective, as well as using the Dynolicious app on my iPhone.
Also, the filter fitted to the stock housing on my car as received is a 6.25" diameter, 2.4" tall oiled gauze type, so it has a useful area of 50 sq inches (about 300 cfm potential), or about 33% more than the muscle unit. So more area for the pressure differential between engine and atmosphere to work on, which perhaps explains why what remains of the shrouding is having no discernible effect.
Perhaps on a proper and well monitored chassis dyno you could pick out the difference in engine performance, especially at high rpms, but in the normal driving range (which I would define as up to about 4500 RPM) the performance difference, if any, has to be small.
I suspect that the louder intake sound from the open element makes people feel the car is faster
Now, the better flowing exhaust of the stage 1 (or any other high flow design) is the real deal in terms of enhanced performance and drivability...but that's well covered in other threads.
