VAFC settings
 

can some one please explain the settings on a VAFC? :-\

am i right in thinking that all the VAFC does is leans the mixture out to stop the car from flooding?

example:

35% 0f 450cc is 157cc?

or am i just mixed up and confused? :-[

Re:VAFC settings
 

Did you read the post about the afc hack? There is a lot of info about it on these forums.

Re:VAFC settings
 

ive beeen reading loads of stuff about the hack (weeks and weeks!) i know how to tune it and set it up(i think!) but i just dont understand what the %'s mean when tuning.

Re:VAFC settings
 

You're confused.

Basically, the precent is the fuel from stock. The AFC doesn't know what injectors you have in there. All it knows is you have a stock flow amount (based on your fuel map stored in the ECU) and your injector pusle durations are based on your MAP sensor. You V-AFC scales the voltage form your MAP sensor, and feeds it to the ECU. The ECU thinks you're at a different manifold pressure than you are, and plots the cells accordingly.

Now, the "percent" you lean out, or richen up is based 0% being no change to signal, thus no fuel correction.

A change of +10%, would richen up your mix by 10% over stock by calculating a new MAP signal and sending it to the ECU.

Now, your next question would be, "How do I know how much to lean it out for the injectors?". Good question. :) Think about this.. Your stock injectors are 240cc. Your new ones are 450cc. What is the percent of increase over stock? The answer: 46% more flow in the same pulse duration. Now, to compensate for that, you lean out (remove fuel) through your V-AFC. This is where you get the -45% settings. Now, in a turbo application, that would be too lean due to increased air flow, so, you richen up from there. Personally, I run -38%@1000 and 18 inHg, and increase to -32%@8000 and 10psi.

..got it? ::)