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

so why would you be at that point in the maps? if the afc is cut out enough just to where the ecu will read around o vacuum wouldnt it use the maps around there?</TD></TR></TABLE>

from what I understand (and I have not read all about how to install the VAFC HACK, so correct me where I need to be corrected). The VAFC manipulates how the ECU fuels the motor/inj by decreasing the MAP value the ECU thinks the motor is actually seeing. So while a VAFC HACK equipped motor is running it will always be running at what it thinks is a lower MAP value. And according to the ignition maps, a lower MAP value will have the ECU fire the spark with MORE timing advance.

 

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

from what I understand (and I have not read all about how to install the VAFC HACK, so correct me where I need to be corrected). The VAFC manipulates how the ECU fuels the motor/inj by decreasing the MAP value the ECU thinks the motor is actually seeing. So while a VAFC HACK equipped motor is running it will always be running at what it thinks is a lower MAP value. And according to the ignition maps, a lower MAP value will have the ECU fire the spark with MORE timing advance. </TD></TR></TABLE>

well think of it this way...the afc lowers the map value but the boost brings the value back up and if you only let the ecu see just enough to where its not throwing a code then it should be right at 0 vacuum and not in vacuum anymore. hence the reason why you dont need a missing link with the afc trick...does this make sense?

 

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

well think of it this way...the afc lowers the map value but the boost brings the value back up and if you only let the ecu see just enough to where its not throwing a code then it should be right at 0 vacuum and not in vacuum anymore. hence the reason why you dont need a missing link with the afc trick...does this make sense?</TD></TR></TABLE>

The whole reason for altering the MAP signal is to get the proper injector duty cycle for larger injectors. You have to offset the MAP signal by the same % your injectors are larger than stock.

 

I give up =P

 

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

I think you are giving up because either you have specific psi #'s in mind or you don't understand the timing table? You cannot adjust the AFC to see 0 vacuum/psi just so you can run timing there. The AFC controls the MAP pressure so that the LARGER injectors will fuel correctly, usually people go from 240-&gt;440 cc's so you're going to cut fueling by almost half. Regardless you are going to run too much timing ignition advance using the AFC hack controlling injectors of a change so large and on stock timing. This is what I understand, I don't swear to be correct... so correct me where you see fit.

[I do not run any AFC, nor have I even ever touched one. I just want to know EXACTLY what happens when people run it in the "HACK" setup]

 

usualy engine detonaiton happes just after leaving gas pedal while the map sensor reads 0 vac right?

like while the you shifting gears ??

 

i am running the afc set up on my own car and i was running 15 psi...i know how the afc stuff works its juss everybody else doesnt get the point im trying to put across...think about this...i run 15 psi but my map is maxed out at 10 psi(dunno why) so basically if i let the afc corrections go on the edge to where im not too far into the negative correction zone but not to where it would throw a check engine light for positive map readings...so basically under full boost the car is sending a signal that is near 0 vaccuum so i would not be in the maps that is pointed out in that table posted earlier...fuel is also controlled by fuel pressure to meet the demands since i cant use the afc to add anymore fuel since it would throw a cel...make sense? basically im trying to say the timing maps will not be off to the point shown in the tables...maybe for a split second in the low rpms while its building boost but who cares...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jockobo &raquo;</TD></TR><TR><TD CLASS="quote">i am running the afc set up on my own car and i was running 15 psi..

basically im trying to say the timing maps will not be off to the point shown in the tables...maybe for a split second in the low rpms while its building boost but who cares...</TD></TR></TABLE>

I see where you are at now. yea, you are right for your setup. Just everyone has different setups in mind when they try to talk about what they all assume are the same thing. I'm going to assume you are running a stock MAP sensor so you get capped off at ~10psi (since it cannot read anymore than that). With those 10+ psi boost numbers and your AFC reductions to the MAP voltage, than I'm going to guess you are at that 0-psi/vac portion of the MAP you speak of.

But if you were to run say 5-7 psi, than you'd be way farther to the left of the fuel and ignition maps (and you cannot correct this with the AFC since fueling would already be correctly reduced for the same inj sizing). That would cause the car to fire with much more timing adv., thats what some of us were talking about. Atleast thats what I thought.

again I'll say I do NOT and never had a AFC, just trying to learn more about different types of tuning products and EXACTLY how they work

Just curious, are you retarding timing at your dist. at all? like 3-6 degrees?

 

timing's retarded about 4 degrees at the distributor