what can you actually do with a VAFC? i'm thinking about buying one of a friend of mine, but i want to know what all it actually shows you and what all you can do with it. right now, i think my vtec kicking in at 57-5800 is too high and i would like to lower it to about 5200 rpms.

thanks

 

Depends, what do u have done to your car? Probably best you get it tuned on a dyno too.

 

VAFC is very good at taking fuel away, because it alters map sensor voltage. So, bump up your fuel pressure, little bit bigger injectors and pull out the unnecessary fuel with the VAFC. having said that....


It cannot control ignition timing. If you have some decent compression (11:1 or above) youll have to retard timing manually and richen the mixture which in turn will make you lose some power, but prevent detonation. Like stated earlier, the VAFC works by altering MAP sensor voltage, so if you try to add fuel to it, the ECU will think its seeing boost and not cooperate too well.

mild setups=vafc
semi built - built = hondata

 

you can lower your vtec crossover point with it right?

 

rgr

 

you can have your VTEC crossover at any RPM you want as well as when you want them to disable. only way to set the vtec crossover is on a dyno. also to do it correctly you have to know how to alter the fuel correction.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LsVtec92Hatch &raquo;</TD></TR><TR><TD CLASS="quote">It cannot control ignition timing.</TD></TR></TABLE>

Wrong. Speed-Density metered fuel injection systems use fueling and timing maps that are BOTH indexed by RPM and MAP sensor inputs.

When you **** with the MAP voltage, you ARE messing with ignition timing.

 

Look at the gains I got from just V-AFC and fuel pressure regulator tuning:



Look at those MASSIVE midrange gains! Also notew the peak torque went way up as well.

Again you need a fuel pressure regulator and a V-AFC to get these types of results, because the V-AFC can only trim fuel away. Use the fuel pressure regulator to add fuel across the board to fix lean spots, then trim the now fat parts back with the V-AFC.

Hondata would have gotten me more power though...

 

b18c5-eh2, why havent you gone with hondata yet?

 

You can use it to run 450cc injectors on a boosted motor

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">Look at the gains I got from just V-AFC and fuel pressure regulator tuning:



Look at those MASSIVE midrange gains! Also notew the peak torque went way up as well.

Again you need a fuel pressure regulator and a V-AFC to get these types of results, because the V-AFC can only trim fuel away. Use the fuel pressure regulator to add fuel across the board to fix lean spots, then trim the now fat parts back with the V-AFC.

Hondata would have gotten me more power though...</TD></TR></TABLE>

you also need a wideband O2 and dyno time

well basically you need $$$$$$

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaeg8 &raquo;</TD></TR><TR><TD CLASS="quote">you can lower your vtec crossover point with it right?</TD></TR></TABLE>

Yes you can. <FONT SIZE="15"><FONT COLOR="red">BUT!!!!!</FONT></FONT>unless your engine has major internal upgrades, (ie. pistons, rods, rings, etc.) changing the VTEC crossover point is stupid. You will only loose power and cause damage to your engine. Honda made it so VTEC would engage at a certain point to take full advantage of it. So, <FONT SIZE="10"><FONT COLOR="red">DON'T **** WITH YOUR VTEC CROSSOVER POINT!!!!!!!!!!!!!!!!!!!!!!!</FONT></FONT>

 

Or just cams...the vtec crossover point depends 99% on the camshafts and the powerband overlap between the high and low lobes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BauleyCivic &raquo;</TD></TR><TR><TD CLASS="quote">Or just cams...the vtec crossover point depends 99% on the camshafts and the powerband overlap between the high and low lobes.</TD></TR></TABLE>

Good point.

 

Whatever...I gained a lot of power just from optimizing my VTEC engagement point from 5200 to 4400...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by H23AHybridEG &raquo;</TD></TR><TR><TD CLASS="quote">Whatever...I gained a lot of power just from optimizing my VTEC engagement point from 5200 to 4400...</TD></TR></TABLE>

Until I see dyno numbers I won't believe this. I wouldn't believe it from ANYONE.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LsVtec92Hatch &raquo;</TD></TR><TR><TD CLASS="quote">b18c5-eh2, why havent you gone with hondata yet?</TD></TR></TABLE>

Because I'm done spending money on my car. I'm happy with the way it is, and quite honestly the extra money I'd spend for Hondata for the extra power isn't worth it to me. I haven't been to a drag or auto-x event in over a year, but i do still love driving my car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DOHC4life &raquo;</TD></TR><TR><TD CLASS="quote">

Until I see dyno numbers I won't believe this. I wouldn't believe it from ANYONE. </TD></TR></TABLE>

Well my VTEC crossover was lowered to get rid of that nasty dip, so I think VTEC engagement can effect whp and torque in the midrange especially. Look at my graph as proof of this.

Although we didn't just change the VTEC point either. We changed the fuel delivery as well.

People who buy the V-AFC and think they can play with their VTEC crossover in their car are clueless. You need to be on a dyno to take advantage of a V-AFC.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">

Well my VTEC crossover was lowered to get rid of that nasty dip, so I think VTEC engagement can effect whp and torque in the midrange especially. Look at my graph as proof of this.</TD></TR></TABLE>

I see what you're saying. But what I'm saying is, changing the crossover point on a stock or engine with all the basic bolt-ons wouldn't do any good. And I'm sure that you have more than just intake header and exhaust on you nice little B18c5

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DOHC4life &raquo;</TD></TR><TR><TD CLASS="quote">

I see what you're saying. But what I'm saying is, changing the crossover point on a stock or engine with all the basic bolt-ons wouldn't do any good. And I'm sure that you have more than just intake header and exhaust on you nice little B18c5 </TD></TR></TABLE>

Actually I don't have anything other than i/h/e and the V-AFC, FPR, and rechipped P28.

The engine is otherwise 100% stock including internals.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">Because I'm done spending money on my car. I'm happy with the way it is, and quite honestly the extra money I'd spend for Hondata for the extra power isn't worth it to me. I haven't been to a drag or auto-x event in over a year, but i do still love driving my car.</TD></TR></TABLE>

i know what you mean, i just cant justify spending any more $$$ on my b series, i keep thinkin bout a K....

 

it added 6hp and 6pdsoftorque for me.. after it was tuned.. it is impossible to tune it without a dyno though..

 

lol... dude Brad your screwed stop trying to fighting it.

My VTEC crossover was lowered from 5400 to 4800 when my torque would start to drop. You should have your VTEC crossover where your hp and torque cross.

VAFC made 207whp.


Red (when i first came in) Green (when i tuned)


Green - untuned Blue - tuned.