One of my friends told me that every day I drive my car the computer tries to find its way back to normal with the vafc. He said that it would not happen with hondata or other programable ecus. Is this true and if it is about how long would it take the ecu to find its way back?

 

yes and no.

 

can you explain?

 

yes it does on the stock ecu and no it doesnt on programmable ecus (hondata, etc)

 

best way to get around it is reset the ecu everyday

 

Could someone elaborate on how the stock ecu will begin to correct itself to compensate for a VAFC? And what evidence they have that this is true?

Just curious.

 

how do you reset the ecu?

 

i would also like to know too.

 

The factory ECU has fuel trim adjustment tables that will correct themselves based on O2 sensor readings. However, if you tuned ur VAFC/SAFC properly ur O2 sensor readings will still be within spec, and the ECU won't have to compensate. This only applies to normal driving, anything over 80% throttle is an open loop situation where the ECU doesn't read the O2 at all and goes purely off a preconfigured calibration.

 

so apexi vafc has some use if it is tuned right?

 

hey are you from houston secret agent?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by realis9 &raquo;</TD></TR><TR><TD CLASS="quote">so apexi vafc has some use if it is tuned right? </TD></TR></TABLE>


no. because even though it allows you to fool the ECU into adjusting the fuel maps (only withinn factory specifications) it gives you no control over timing. In fact, it changes timing in a way that you can't control and can possibly make the car run worse than when you started. Just because the fuel mixture is correct, doesn't matter because the timing could be off by up to 20 degrees. The *AFC modfies the MAP sensor signal to compensate fuel trims. When it modifies this signal it tricks the ECU into thinking there are different parameters, so it will use a different part of the fuel map. However, these different parameters also cause the ECU to use a different timing map.

For the same price, and a little more in tuning, you can have a Hondata S100, with total control over what your ECU is doing and how your car runs. The *AFC is fine for cars that there is no other economical tuning device available or if the factory ECU's parameters are generous enough to still allow the car to make decent power gains from the addition of it (i.e. supras). For a Honda, they don't make any sense.

 

So if this is true why are there gains made on the dyno using the vafc? Is it bc you are only talking WOT and open loop on the dyno?