Okay, I may be totally wrong here, but heres how its felt to me.
A few months ago I swapped my standard filter for a Pipercross panel filter. The result seemed to be that it pulled a little better from low revs and caused the engine note to be a little more boomy. It also made it idle a little more lumpy and there were a couple of noticeable flat spots, but overall it felt a little quicker. My 1/4 mile time also improved, but this could have been due to conditions, or me improving.
Anyway, I took the filter out last week to get some work done by Renault, and as before the car went back to running far smoother with a less noticeable drop in two places in the rev range.
Yesterday I had the Magnex cat back system fitted. On the way back from Wales it felt as quick as normal, nice and smooth with no real drops. But I couldnt help thinking it was struggling a little from the mid range and certainly higher up the rev range.
So, my theory being more air is getting out, so therefore it would be good to get a little more in. So I dropped the Pipercross back in.
Ive just been for a quick spin down to Blockbuster, so on the way back I thought Id take a longer route and see how it felt. It now feels spot on, it pulls hard all the way to the red line and doesnt seem to have the noticeable flat spots.
Oh and it sounds amazing
Does my theory make sense, or is it more likely to be in my head?
Thanks
Lee