i will try to explain it this way.
my 07 classic has tors (triumph off road) mufflers now the mufflers are a little bigger so when i back off it rumbles (because muffs r bigger it sucks air back into the system)and when it gets down to about 1500 rpm then it starts to bang and gets pretty loud when the pipes get good and hot. i kind of like it but when i don't i just pull in the clutch and coast till i shift down.
now a lot of the maps dump more gas into it to cure the popping but i would not like this so i have stuck with what i think is the tors map altered with my tunecu.
if i were u i would enjoy the noise and not worry about it.. i have thought that if u put like a big washer on the end of the pipe that would work like stock until high rpm the blow open like the big diesel trucks maybe u would have the best of both worlds.
now the lack of power may be your map u chose or some other prob i do not think that it is your exhaust system.
there is nothing in there that closes off what happens is the bigger pipes looses the scavenging effect
for test purpose u might try closing down the muffs with like a home made bushing.
some have said that they get a flat spot and there r others that r much better that me.
on my pcv it has an o2 optimizer so u can unplug the O2 sensor and plug in the O2 optimizer. i think that it has resisters that send a constant signal to the computer. i am not real certain about using this. have not made up my mind.
the # on my pcv is 21-003 what is yours.
if i have made a mistake i am sure some one will be along to set u right.
