Hi guys, i have a 99 accord i4 and have recently installed an sri and header. The sri was a great mod and i got a snappy throttle response from it. About a week later i installed the header and it seems i have lost a considerable amout of acceleration in the very low rpms as well as the snappy throttle response which ppl have told me is normal. Whats concerning me tho is that from about 1k-3k rpms the sound produced is a kind of fluttering sound. After 3k it turns into a nice growl but before 3k it sounds very odd, kind of a spurting air fluttery sound for a lack of better words. Can anyone tell me if this is normal or what the problem may be? Thanks in advance and sorry for the long post

 

~bump. Anyone have experience/knowledge about this matter?its been driving me nuts

 

Resonence? How good quality is the header?

 

possible exhaust leak? that seems to be a common problem with headers, especially poor quality ones. try retorqueing the header bolts back to spec again.