injector sizing, afc

[rush0]

Is 370 the largest possible injector I can use with a afc on ka-t? I would really like to get 480's but I hear the formula is arouhnd original size + half.

[Structure240sx]

the safc can trim down 50% of an injector. the stock injector on the ka is 270cc. times this by 2 and you get the max injector you can run, 540cc. i run 550cc injectos off the stock ecu and safc. the ecu can adjust slightly itself so my idle is damn near perfect.

i also used to run 480's which are no problem at all.

basically the biggect you can go with the safc on a stock ecu is 550cc

[Def]

The bigger the injector you use, the more advanced your timing will be for the power you're putting out. It happens because to get the right pulsewidth, you find yourself on a column that the factory tuned for maybe 200rwhp, but you're fooling the ECU into giving you the right inj. pulsewidth for 300rwhp. So you get the fuel right, but the timing is more advanced than you might like.

[daniel240]

does anyone know if you could run bigger than 540cc injectors if you are using a hacked mafs. using a hacked mafs, the correction will be much smaller than it would with the stock mafs. im using a hacked mafs with 370's and a safc and my correction on the safc is only somewhere around 10%. i just thought about this after reading this thread. it seems like you should be able to run at least 640cc's or close to that by hacking the mafs for 370's.