VAFC Tuning...
Well Ive read a lot of threads of people working with VAFC and its obvious that most people are favored at Honda S200 and stand alone management systems. Unfortunately not all of us have the funds to do so. I just recently bought my VAFC for $35 from my best friend. Pretty damng good and installed. My questions are should I try tuning it myself and learning or have a profesional do it. I have a 1997 Civic EX with a USDM GSR I/H/E and Cam Gears. Nothing special. Any suggestion would help.
Unless you have experence i would leave that to the professionals, thats one of those things that will severly screw up your car if not done right.
First of all you'll also want a fuel pressure regulator as well, because the V-AFC can only trim fuel away, not add fuel.
You'll want to have someone familiar with tuning tune your car on a dyno, and the way he'll end up tuning is using a wideband o2 sensor to read air/fuel ratios.
If the car is running lean anywhere a V-AFC cannot fix that. The tuner will need to increase the fuel pressure to make any lean spots stoich (basically that means not rich, not lean) and in doing so any spots that were already stoich or even rich become way too rich, because the fuel pressure can only be adjusted across the entire rpm range.
THIS is where the V-AFC comes in handy. The V-AFC will allow the tuner to trim the fat spots in the a/f map back to stoich, when in turn will increase whp and torque. The V-AFC can trim fuel back at 500rpm increments, meaning it can alter the fuel in spots that need the fuel trimmed away, unlike the fuel pressure regulator which just does it across the entire RPM range.
A perfect example of this is my own B18C5 that I was running on a chipped P28 with just a fuel pressure regulator. Evidently the guage I used to set the fuel pressure was wrong, because my "before" a/f sucked until the tuner tuned my car after I installed the V-AFC:

So anyone who talks **** on a V-AFC can look at that graph and see it can do wonders if installed correctly and tuned in the right hands on a dyno. You got a deal at $35.00.
In the end Uberdata/Crome/Hondata is a better route because it's more precise, you can adjust timing, and you can add features like drag launch, full throttle shift, check engine shift light, etc.
You'll want to have someone familiar with tuning tune your car on a dyno, and the way he'll end up tuning is using a wideband o2 sensor to read air/fuel ratios.
If the car is running lean anywhere a V-AFC cannot fix that. The tuner will need to increase the fuel pressure to make any lean spots stoich (basically that means not rich, not lean) and in doing so any spots that were already stoich or even rich become way too rich, because the fuel pressure can only be adjusted across the entire rpm range.
THIS is where the V-AFC comes in handy. The V-AFC will allow the tuner to trim the fat spots in the a/f map back to stoich, when in turn will increase whp and torque. The V-AFC can trim fuel back at 500rpm increments, meaning it can alter the fuel in spots that need the fuel trimmed away, unlike the fuel pressure regulator which just does it across the entire RPM range.
A perfect example of this is my own B18C5 that I was running on a chipped P28 with just a fuel pressure regulator. Evidently the guage I used to set the fuel pressure was wrong, because my "before" a/f sucked until the tuner tuned my car after I installed the V-AFC:
So anyone who talks **** on a V-AFC can look at that graph and see it can do wonders if installed correctly and tuned in the right hands on a dyno. You got a deal at $35.00.

In the end Uberdata/Crome/Hondata is a better route because it's more precise, you can adjust timing, and you can add features like drag launch, full throttle shift, check engine shift light, etc.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 »</TD></TR><TR><TD CLASS="quote">First of all you'll also want a fuel pressure regulator as well, because the V-AFC can only trim fuel away, not add fuel.
You'll want to have someone familiar with tuning tune your car on a dyno, and the way he'll end up tuning is using a wideband o2 sensor to read air/fuel ratios.
If the car is running lean anywhere a V-AFC cannot fix that. The tuner will need to increase the fuel pressure to make any lean spots stoich (basically that means not rich, not lean) and in doing so any spots that were already stoich or even rich become way too rich, because the fuel pressure can only be adjusted across the entire rpm range.
THIS is where the V-AFC comes in handy. The V-AFC will allow the tuner to trim the fat spots in the a/f map back to stoich, when in turn will increase whp and torque. The V-AFC can trim fuel back at 500rpm increments, meaning it can alter the fuel in spots that need the fuel trimmed away, unlike the fuel pressure regulator which just does it across the entire RPM range.
A perfect example of this is my own B18C5 that I was running on a chipped P28 with just a fuel pressure regulator. Evidently the guage I used to set the fuel pressure was wrong, because my "before" a/f sucked until the tuner tuned my car after I installed the V-AFC:

So anyone who talks **** on a V-AFC can look at that graph and see it can do wonders if installed correctly and tuned in the right hands on a dyno. You got a deal at $35.00.
In the end Uberdata/Crome/Hondata is a better route because it's more precise, you can adjust timing, and you can add features like drag launch, full throttle shift, check engine shift light, etc.
</TD></TR></TABLE>
good info. your pic no workie though. do you have a link to it? would like to see the curve after the tune.
You'll want to have someone familiar with tuning tune your car on a dyno, and the way he'll end up tuning is using a wideband o2 sensor to read air/fuel ratios.
If the car is running lean anywhere a V-AFC cannot fix that. The tuner will need to increase the fuel pressure to make any lean spots stoich (basically that means not rich, not lean) and in doing so any spots that were already stoich or even rich become way too rich, because the fuel pressure can only be adjusted across the entire rpm range.
THIS is where the V-AFC comes in handy. The V-AFC will allow the tuner to trim the fat spots in the a/f map back to stoich, when in turn will increase whp and torque. The V-AFC can trim fuel back at 500rpm increments, meaning it can alter the fuel in spots that need the fuel trimmed away, unlike the fuel pressure regulator which just does it across the entire RPM range.
A perfect example of this is my own B18C5 that I was running on a chipped P28 with just a fuel pressure regulator. Evidently the guage I used to set the fuel pressure was wrong, because my "before" a/f sucked until the tuner tuned my car after I installed the V-AFC:
So anyone who talks **** on a V-AFC can look at that graph and see it can do wonders if installed correctly and tuned in the right hands on a dyno. You got a deal at $35.00.

In the end Uberdata/Crome/Hondata is a better route because it's more precise, you can adjust timing, and you can add features like drag launch, full throttle shift, check engine shift light, etc.
</TD></TR></TABLE>
good info. your pic no workie though. do you have a link to it? would like to see the curve after the tune.
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