So i ported my throttle body out in stages, really it was just a matter of eliminating the machining edges out of the TB. It is a venturi in fact to speed up airflow and enhance ram effect at low RPM. Smaller opening on intake side and you can visibly see the reduction looking through the TB. First time (smoothing edges) was fine but this time i decided to do a little filing through the entire thing. Of course i have the high idle and stupid surging dropping surging dropping cycle in neutral warmed up.
I know an idle air volume relearn should fix this fine but for some reason i can't get it to settle down. It is entering relearn mode (using key/pedal sequence to go into relearn mode) as detected by flashing then solid MIL at KOEO. Start it up and same shit, never settles down, no nothing. I can go pick another TB at the wreckers but i'd rather get this working.
I don't think i've over extended the thresholds that the PCM can adapt to, since a B16 MR20 Sentra guy sent his TB to Maxbore and they increased the bore by at least a few MM (new throttle plate, machining), and he said he never had any problems.
If it's the same procedure as used on the Muranos, it's just a royal pain. I had to go through the procedure probably 20 times before it finally took it permanently. Luckily I haven't had to do anything on the V that required unplugging the TB.
Not a worry, i think what i did was take a bit too much off the seat of the throttle valve ie the closed position, so it would have a new higher idle point. Wasn't a loss though, as i can send it off to MaxBore to do it properly. Buddy on allsentra got his bored out from 59 to 65mm.