whats the main differences between the 2, and what can be a gain of using them both if possible.

 

???

 

An adjustable FPR (fuel pressure regulator) is a mechanical device that allows you to adjust the base fuel pressure in the system. A V-AFC is an electronic device that allows you to tune the actual fuel curve by intercepting and manipulating the MAP signal, and also allows adjustment of the VTEC activation point.

They basically work in conjunction, and in most cases the FPR is used to increase the fuel pressure, and the V-AFC (or similar device) is used to adjust the curve where necessary.

 

so if i buying a V-afc i dont really need a FPR?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BLK99VTECR &raquo;</TD></TR><TR><TD CLASS="quote">so if i buying a V-afc i dont really need a FPR?</TD></TR></TABLE>

In most cases you will still need the FPR, because there reaches a point where the V-AFC cannot add additional fuel (this is a limitation inherent in the way the unit functions). You're better-off with both, and a FPR isn't terribly expensive anyway.

 

Most people use the FPR to add fuel and the VAFC to remove fuel where needed.

 

hello padawan. do you really know how to manipulate VAFC? i'm still new in this items. i'd already installed it in my EK ( B16A NA engine ). I will install my new head which been ported and polished, with TODA Type C, TODA dual valve springs, CROWER oversized valve and titanium retainers. CTR intake manifolds and 70mm throttlebody. stock B18C5 block. Can you teach me how to manipulate my VAFC and how to enrich my fuel in each RPM? how much should reliable for High cam and Low cam points?

Thanks.

 

Honestly, you've been misinformed.

Basicly, a stock Honda ECU doesn't like t do what it isn't programmed for. An adjustable fuel pressure regulator does exactly what it's called. It adjusts fuel pressure. Now, think about the effects of this device:

1: The ECU is programmed for 38 psi at idle, and knows the rate at which the pressure rises on the factory regulator. What happens when you change this value? The ECU shows a rich condition, and corrects by dropping the injector duration...... Total net gain.... Nothing.

2: If you take the fuel pressure higher than the ECU can correct for......you're blowing black smoke, check engine light comes on because the ECU thinks the O2 sensors are out of range because it doesn't know that you've bumped fuel pressure.... Net gain.... Nothing.

Now, on to the VTEC Air Fuel Controller.

1: This intercepts the signal to the injectors from the ECU, and adds a percentage onto the injector duration signal. What happens when the O2 sensors see a rich condition?? Simple, the ECU auto corrects. What happns when the ECU can no longer correct??? Black smoke, check engine, O2's out of range.

Now, let's use the VTEC portion of the V-AFC..... Lets engage VTEC early at say.... 4,000 RPM's. The ECU still thinks it's on the low cam, and therefore doesn't switch over to the high cam fuel and timing map untill the stock setting for VTEC would notmaly occur. Net gain again... Nothing.

Seeing a pattern here? And do you see the REAL problem behind this??? The stock ECU.

What you NEED to do in order to play with a Honda fuel management system, is get some type of complete fuel management computer, such as Hondata, AEM, Halltech, etc.... You can also have the ECU re-chipped with the correct fuel and timing maps for your particular application.

But in any case, you're doing nothing to you engine management unless you let the ECU do it's job. And ypou do that by giving the ECU proper information through proper programming.

Just get Hondata, and 3 hours at a dyno.

You'll end up much happier.

Stick

 

for you to say the vafc doesn't produce any gains is (IMO) wrong. Yes there is a limit to its abilities, but it can produce hp by adjusting fuel. I have seen a dyno where the tuning of the vafc produced 22 whp.

the guy is on H-T (can't remember his user name though) and works at a shop in my area (which is where i saw the dyno). He will be tuning my vafc in the near future.

I also have a dyno of my current set-up, where the vafc made 6 whp. It was only an hour of tuning and they weren't using wideband (they used EGT ). But it still produced 6 peak whp, i can post the dyno if needed.

The vafc is worth the money if tuned correctly, granted hondata is preferred, but price is always a factor.

 

u can only do things right so get the hondata there program aloows u to mess with alot of isht like "vtec" engagement , fuel preasure, rev limit, and the like. hondata.com the s100 and the s200 have all kinds of goodies including a guffin shift light