Luke530

NOT SURE IF THIS IS THE RIGHT TOPIC FOR THIS FORUM, MODS, FEEL FREE TO MOVE IT

(YES, I did use the search function)

...but this is probably the best place to ask (knowledge-wise)


I'm a little confused about VAFC settings.

Lo and Hi throttle:
Let say: Lo=10% and Hi=50%

1.) does that mean that BELOW 10%, the VAFC uses the LVT settings and ABOVE 50% the VAFC uses HVT settings?

2.) in between the 10% and 50% calculates something in between the 2 settings?

3.) I want to set my vafc so that it does not work below 50% throttle. I only want it to kick in when I'm actually going to have use for it (under WOT, and maybe right before or right at the V/T engagement point)

4.) I also don't understand the V/T unmatch... can anyone enlighten me?

Thanks in advance!!!
Luke

Luke530

Anyone?

blackey

If you set them at 10% and 50% it means that below 10% it uses the LVT settings. Between 10% and 50% it interpalates, and above 50% it uses the HVT settings.

If you set the LVT and HVT settings the same, and set all the LVT settings to 0, you will only get the HVT settings above the point you set it at.

AKA if you set Lo=80% and Hi=80%, and all LVT settings to 0, all HVT settings to what you need... then:

You will only get corrections above 80%.

AssassinJN

Isn't one of the biggest advantages of the vafc with an ap1 increased gas mileage + hp/tq at partial throttle and esp in lower rpm range? I thought I had read that ap1's run especially rich in these situtations.

Searching threads now...

blackey

Yea, except the computer has targets and will relearn after you set it in the vafc. Only works at WOT, at least that's where the gains will stay.

Luke530

ok, so say I set my LVT and HVT at the same %

(I saw a few post sayin 80%LVT and 81%LVT, btw? any difference?)

can I also set it to work above a certain RPM? say

75% LVT & HVT
and only about 4000 or 5000 or 6000rpm?


Also, I have read about the ECU being in closed and open loop.
would the ECU be operating in closed loop only in LVT and open in HVT?

Finally, what is V/T (VTEC) unmatch? I really don't seem to understand it.


Thanks!
Luke

blackey

80% and 81% is the same. If you don't make any changes below the rpm you want to the fuel tables you can just change the fueling where you want it. That being said, why not change it all all RPM's al long as your at WOT? Since the ECU does not monitor the O2 sensors at WOT it just uses the base map- aka it's in open loop at WOT. If the ECU is in closed loop any changes you make to the map will be tuned out by the ECU.

VTEC unmatch - Lets say you set the new changeover point to 5000RPM. Unfortunately the stock ecu will still think its in the lo cam until 6000. It doesn't know what the VAFC is doing. So from 5000 to 6000 rpm the fuel table will be significantly off. This is where VTEC unmatch comes into play. It will add a percentage of fuel to just that region. Since VTEC has different shift points from low->hi and Hi->Lo there are two values for this. One for each direction.

Luke530

Thanks for the explanation!

Is there any certain percentage to add/take away during the V/T Unmatch? How do I figure this out? *I suppose wideband 02 tuning on a dyno*

also, If I set my
Lo-Hi to 5900 or 6000
and my
Hi-Lo to 5800 or 5900

I wont really need the V/T Unmatch, will I?

Thanks Again!

blackey

If you set it at factory you will not need it, that being said, you can pick up some really good HP in that region. You absolutely need a wideband to set it up, and to set up VTEC you will need a dyno, but you already knew that!

Luke530

Perfect! Thank You!