As many of you I have the 1600 sec. KG rail , Aero FPR , P F C and I have bought a set of resized primaries@ 720. Even with the large porting are there tunnablity issues with these being TOO big. Mark57 has a Datalogit ( to help me) but I have seen some have had idle issues and low rpm issue? Worse case scenario I can get stock 550 again.(mine dry rotted and were stuck ......broke them) Or can the larger porting and reduced inj% work out just fine?



Nothing is assembled as of yet. Thanks L8T.



P.S. Can ya help a bro out if you know where a map of this setup is?

 

PowerFC made my car purr like a kitten with stock ports and 850cc primaries. Keep in mind it probably reduced the fuel pressure at idle like the stock ecu. As soon as the aftermarket regulator went on the idle went to hell and needed significant retuning.



It can be done though, keep at it.

 

I have kgparts 870cc primaries. I had to make some changes to my fuel map but the car operates at low rpm and idle as it did with the stock 550s