so this may seem like a stupid question but here it goes. what is the cause of the sudden surge of power right around 5000 rpm. i have a helix downpipe, and cobbstage 2 reflash. but this characteristic was there before the mods only to be emphasized by them. the car has a gradual surge of power around 3500-4000, then a large surge again at 5000 until 7000. now i know it isn't boost, since it is at full boost well before that. there are only two things i can think of... 1. that's when the cams come in, or 2. it has to do with those tumbler valves. whatever it is, it is a characteristic that i am not really too fond of and would like to change.

any thoughts on the matter would be greatly appreciated.

 

There may be something going on with your downpipe and the cobb reflash. Cobb 2.0 was designed with a bellmouth downpipe in mind. The HKS downpipe is no better than stock where it meets the turbo. Perhaps this surge is due somehow to the different behaviour of the wastegate gasses.

 

Might not apply if you are actually accelerating when the surge occurs. When I got a surge my clutch was on the way out. Early on the "Surge"/slip had the effect slipping the clutch as if you were launching the car which made you feel like you were taking off. Later it just slipped and croaked. Just a thought.