i have a 2000 gsr w/ drag gen 3 turbo kit, i'm running walbro 255 pump and rc 440cc injectors, and my car idles like ****. my question is since the vafc2 only goes in increments of 1000. does that mean from 0-900 can't be adjusted or are they the same as whatever i set 1000 at? could i be dumping too much fuel if my car idles below 1000 rpms? would 310cc injectors help my idle at all? my car idles so low sometimes it shuts off.

 

Injector pulsewidth at idle in some Hondas, when running AFC hack with 440/450cc, can be too big and you will always run rich. Smaller injectors would help idle, but that is the *last* thing you want to do with an AFC hack.

AFC hacks advance your ignition timing in the low boost figures, with how the MAP signal to the ECU has been altered you not only read a fuel value for a lower engine load, but you read an ignition value for a lower engine load - right off the part throttle cruise portion of the ignition maps, around 42 degrees advance. Stock GSR final timing at WOT/atmpspheric pressure is 28 degrees. Yup - 14 degrees too much advance at transition into boost. At 5 psi, the average AFC settings still leave you 7 degrees advanced of where you should be at 0 psi... not liking the sounds of this, eh?

So, low boost with an AFC is out. You have to run the most boost your MAP sensor can read to have your timing at full boost minimized. Run 9-10 psi, Honda MAP sensors do not register 11 psi despite Hondata's lies. 10 psi on a GSR will exceed what a set of <440cc injectors can handle.

Keep in mind BTMs do nothing to address the AFC hack ignition curve, and you can't manually retard your distributor for a little retard under full boost as the OBD2 ECU compensates for that. I'd really recommend you convert to OBD1 and run Uberdata, the cost of your AFC will finance the conversion and leave you with a little beer money to boot.