OK guys, there have been multiple threads about the VAFC and our beloved Preludes.

First off here are a few Pages and Threads that you should read to answer any questions that you have. this is far from an all inclusive thread. there are so many VAFC threads that i could never keep this fully updated.

common questions -

CAN I USE THE VAFC ON AN SH?
yes you can.

IS IT WORTH IT?
That is all up to you. it all depends on your application, and your goals for your Prelude.

CAN I JUST SET MY VAFC TO MY FRIENDS SETTINGS?
NO!!! every car is different. every mod and the cars history will determine where the settings should be at. DYNO DYNO DYNO!!!!

CAN I INSTALL MY VAFC BY MYSELF?
yes you can install anything if you are capable, but it is up to you if you want to risk it. most shops will charge around $150 for install and $130 for dyno time and tuning. for this same price you can get a wire harness from many of the sponsers here and install in in minutes by yourself with only a 10mm socket to remove the ecu.


APEXi's home page for the the VAFC
http://apexi-usa.com/electronics_vafc.asp
http://www.ntpog.org/mods/fifth-afc/afc.shtml

A FEW THREADS FROM THE PRELUDE FORUM ABOUT THE VAFC

will VAFC help with alreadyI/H/E on a 00lude

does this damage my car???

jsut got the VAFC, and now i have a few questions. - describing functions.

Setting vafc to stock settings how??

VAFC - should I bother?

VAFC...problem...HELP

SAFC and VAFC experts . please help!!!!

vafc question. what is prs mean and is it bad if at full throttle it reads in the +s ? what is in 6

VAFC install HELP

reset my vafc - vtec kicks in at 5,800 rpm? WTF?

VAFC Install (5th Gen) HELP...

vafc settings for h22

Apex'i VAFC measurments

VAFC Gains

VAFC is it worth it?

VAFC and OBDII questions

help with vafc tuning, vtec x-over.

VAFC RPMs of Tach RPMs

tuning vafc

a little off topic but has some good VAFC info in it

Let's settle the O2 sensor agrument once and for all. (ODBII sucks)


VAFC HACK THREADS

vafc hack help!!

VAFC hack vs AEM EMS at 7PSI...

INSTALL PICS

VAFC Install (5th Gen) HELP...

AFTER INSTALL

VAFC installed!!!!!!!!!!!!!!!!

tuned vafc on stock lude.


If anyone has any problems with this thread or the contents thereof, or would like something added to the common questions etc... please PM me and i can add it for you.

Doug




Modified by Shakes at 12:15 AM 10/3/2004

 

You can use your friend's settings, assuming its just basic mods. It won't be completely optimal, but it can help. For instance, all H22A's run rich with basic bolt-ons, you mild lean in VTEC will 95% of the time help power.

But yes, it is NOT RECOMMENDED, you should dyno it

 

Also don't use one of them Butt Dynos, they suck!

 

Now, who wants to explain the unmatched fuel setting?

 

im not totally sure, but isnt the unmatched settings during that "grey area" of vtec crossover... where your ecu sends a signal out, the vafc takes it and alters the signal, and there is just a "unmatched" grey area there where the signal might become distorted or something? the wording might not be right but i believe thats what its for? someone correct me.

 

So is the % difference in this area does what? Since IIRC the low cam goes up to 6000 and the high cam starts at 4000 or something? Or something like that... The main point being that they overlap a little bit. I assume that the V-AFC takes the fuel settings of the cam that it's on, so it depends on your VTEC transition point. Is the unmatched fuel setting (say I set my VTEC transition point at 4800) for the area between 4800 and 5000rpm (the first hi cam fuel point). The instructions really don't cover this area... It's also strange since almost ALL the S2k people have some setitng in here, while I see almost no Prelude settings w/ it in since I believe mostly is because no one knows what it does exactly.

http://www.s2ki.com/forums/showthrea...threadid=51969


edit: I went to Apex-i USA's web site and this is what they describe it as...
"When the VTEC engagement point is modified, the difference in settings require fuel correction.

The VTEC Unmatch function allows this correction of fuel between the ECU VTEC engagement / disengagement and VAFC VTEC engagement / disengagement. Please keep in mind that any value entered here will be added on top of the Wide and Narrow Throttle Maps."

I'd assume by this you'd want a positive number in this area to get a little bit more fuel into the mix since you're throwing in a ton more air earlier. The next time I dyno I'll try bumping this up to 3-4% and see what happens. I had a pretty flat A/F ratio last time though.


[Modified by TimeRacer, 9:04 AM 3/8/2003]

 

i hear you want it to be slightly lean during vtec engagement... dunno. maybe i'll mess with that alittle with some more dynotime. see if that helps any.

 

Why would you want to be lean during the VTEC transition? If anything at the transition is when it'll cause the largest problem since it's just opening the valves more giving more air so you're probably automaticly lean at that point in any case...

 

bump for the Update.

 

very informative post....but theres always gonna be a bone head with one of these...


yeah i just got a vafc can i use my friends settings???...lol

 

yeah i know. its killing me right now, i have my VAFC in the trunk. just dont have the $160 for dyno/tune time.

 

just some FYI, a VAFC WILL work on OBDII cars, and if you know anything about how OBDII works, then you know that a VAFC is made to actaully be more compatible with an ODBII ECU, it reads values the same as an ODBI ECU does

 

CAN I INSTALL MY VAFC BY MYSELF?
yes you can install anything if you are capable, but it is up to you if you want to risk it. most shops will charge around $150 for install and $130 for dyno time and tuning. for this same price you can get a wire harness from many of the sponsers here and install in in minutes by yourself with only a 10mm socket to remove the ecu.

I was wondering what sponsers make these harnesses? Would it be worth it if I decided to remove the system w/o destroying the stock wiring? I think it would but any info would be greatly appreciated. Car is an 01 prelude with intake header and exhaust.