hey guys, is it possible for me to run 680cc injectors on my h22a and tune it down with the vafc? i plan on turboing my lude very soon, but i wanna know if i can use the vafc to tune it down enough with the 680's? i've heard of people adding a 10k pot from radioshack or some thing like that, and this allows u to tune the injectors down to any amount u want. anyone know anything about this, and does it really work? can u guys help me out with this?
thanks
daniel

 

It is possible. I've tuned afcs with up to 720s and still maintained drivability.

 

please share how.

i thought the AFC hack was limited to 10 psi because the SAFC cannot correct map signal passed 10 psi.
also thought it was limited to 440cc's because it can only correct -50/+50 on fuel, and anything else would be too big to idle.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b_ron007 &raquo;</TD></TR><TR><TD CLASS="quote">please share how.

i thought the AFC hack was limited to 10 psi because the SAFC cannot correct map signal passed 10 psi.
also thought it was limited to 440cc's because it can only correct -50/+50 on fuel, and anything else would be too big to idle.</TD></TR></TABLE>

This may help explain some...
https://honda-tech.com/zerothread?id=137901

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by USDMDC2 &raquo;</TD></TR><TR><TD CLASS="quote">

This may help explain some...
https://honda-tech.com/zerothread?id=137901 </TD></TR></TABLE>

thats a good link, anyone else got any more info on this setup?
thanks
daniel

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b_ron007 &raquo;</TD></TR><TR><TD CLASS="quote">please share how.

i thought the AFC hack was limited to 10 psi because the SAFC cannot correct map signal passed 10 psi.
also thought it was limited to 440cc's because it can only correct -50/+50 on fuel, and anything else would be too big to idle.</TD></TR></TABLE>
The amount you tune down your injectors would depend on how much fuel you need. If you're running a big enough turbo to require bigger than 450's than it should be fine. But running more than 10 psi with a piggy back setup probably isn't the best idea.

 

ttt

 

You can't run injectors bigger than about 500 cc/min, without making other changes to the amount of airflow the ECU sees (different MAP sensor, or temp sensor hacking).

The SAFC/VAFC can only reduce the pressure signal by 50%, which means that injectors twice as big as stock are the biggest you can compensate for.

The other thing to consider is that by modding the pressure signal to the ECU, you totally banjax the timing maps, so you need to do something to combat that. The normal method is just turning the distributor to retard the timing 5-10 degrees.

 

i used 720's , 22 pounds of fuel pressure idling, fmu, stock timing. the safc is much easier to use than the vafc on the h22. it was perfectly drivable. 680's should be no problem.

 

Just keep in mind that if you're using 720's at a base pressure of ~25 psi, then they're really only flowing 550cc/min.