adding mid box cause knocking?

[ahren]

Dear Sifu,

i am running on 1600cc NA with BOT. my exhaust setup is 2.5" downpipe + mid box +2" straight pipe + straight flow muffle. Due to tak boleh tahan with the loud exhaust, i added another mid box.

my question is why adding another mid box (adding restriction) will cause engine knocking? supposingly air restricted, the A/F should be rich. I suppose knocking is caused by A/F too lean.

any sifu enlighten me?

thanks

 

[liz@rd]

1.6 NA Bot ,any piggyback ? done your a/f reading ?

 

[mydaus]

BUMP!!
Anyone can explain??

 

[contreasjun27]

well seriously the answer might be on management. Is there any management being setup like a piggyback? coz knocking occur mostly because of fuel problem dude.