Hey there, I am a new user and '06 S40 owner.I searched the threads for information on the jetting but there are so many coflicting pieces of info out there.  I have a Jardine slip-on (installed) and a K&N filter (uninstalled).  I read that the engines are tuned very lean from the factory somewhere else so, I ended up ordering a Dynojet kit.  From some of the posts I read, it appears that even the largest jet size (146) will not clear up my backfiring on decel issue?  Can someone please clarify? Any help is appreciated.

arteacher wrote on 08/16/12 at 13:37:19:


I found this post earlier.  So my understanding is if the stock size is 142.5 (Mikuni) the Dynojet equivalent would be 152.  Therefore the largest size in the kit is WAY too small?