Hi,

I've been wondering why both times I have put an exhaust and intake on my cars, I haven't noticed the major power increase untill a day or two later. I was wondering if the factory ECU adjusts to the new flow of air / boost / fuel etc own its own? Would this be true, because the first time I drove my old sti and current evo after modifying it I didn't really notice the major difference straight away.. It's like the ECU adjusts after a few drives and gives itself a small tune.

Would this be correct?

 

i think the ecu will try to compensate for more air in and freely flowing exhaust to a certain point. it can adjust itself out to run as best as it can with the set peramiters it has in th ecu

 

this is why most people (i believe most) will put those parts on, disconnect the neg. terminal on their batt., and then let the card idle for 5-10 minutes. i noticed an instant difference with just intake, tbe, and licp.

 

As far as I am aware the ECU doesnt correct for these items. A tune is needed to correct the rich/lean after such installs. The evo runs rich from factory so assuming you put a filter on doesnt help the problem. Hope that helps.