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-   -   Vafc Map! (https://www.homemadeturbo.com/engine-management-10/vafc-map-88402/)

streetspeed607 01-26-2008 07:31 PM

Vafc Map!
 
Can anyone give me a vafc "base map" 97 single cam non vtec t3/t4 .57 just somethin to get me started.


Thanks


P.S. Is not my car

Slo_crx1 01-26-2008 08:27 PM

Re: Vafc Map!
 
There is no such thing as a "base map" on an afc. Read the sticky above and it'll give you some insight, but otherwise you're heading into dangerous territory.

streetspeed607 01-26-2008 09:28 PM

Re: Vafc Map!
 
yes i do know that! I said "base map" meaning as in what are some SETTINGS people are running on the a similar setup so i can start there and go from those "settings" ... Honda-tech gave me the same response ahahahha stop over readin!

streetspeed607 01-26-2008 09:31 PM

Re: Vafc Map!
 
something like this but not for a dsm!!!

1G Turbo 16G

This car seemed to run lean to begin with. Even with 550s and all the honeycombs in,
had to richen things up quite a bit to get the fuel trims at 100% (normal). These
settings are with the honeycombs out and the adjusting screw out flush.
Low Setting:
1K +19 2K +12 2.5K +9 3K +6 3.5K +5 4K +5 4.5K +5 6.5 +5
High Setting:
1K 0 2K +3 2.5K +3 3K +4 3.5K +4 4K +4 4.5K +4 6.5K +8
Th-Point
Lo 30% Hi 80%

Slo_crx1 01-26-2008 09:46 PM

Re: Vafc Map!
 
You kinda of have to sit down and do the calculations for what your new injector size is to get a general idea, and make sure you have a wideband o2 hooked up and running when you take the car out for a test run. Read this for a quick way to figure out roughly what your settings might be, and keep in mind the numbers listed will probably not be exact for your car...


2-4) What settings should I use for X size injectors with X amount of boost?
This is one of the most misunderstood concepts about using the AFC hack. Lets examine each part to determine your correct settings. To begin, please read question 2-2 before continuing. Now that you understand a little bit about injector sizing with an AFC, we can talk about settings. If you decide to use something other than 450cc injectors, you may want to start with lower boost settings (at the wastegate) and build up from there, keeping the same fuel compensation settings in the AFC.

This will give you the upper limit for the current injector size.
As for obtaining those settings there are a couple of things to explain. Fuel flow rate difference.

This is the difference in flow based on the stock injector flow rate. For a Honda, 240cc injectors are stock. If you increase to 450cc injectors, your flow rate difference is a 46% increase. How do we figure that? Simple math: percent_of_difference = ((240 / new_injector_size) - 1) * 100
Second, an AFC does not control fuel injector pulse duration. This means we cannot compensate for injector latency in the fuel table for our larger injectors. Injector latency describes the scientific characteristic of how long it takes the injector to physically open. The larger the injector, the higher the latency. Since AFCs do not control the pulse duration directly, we compensate with a fixed percentage subtraction, otherwise, we would run lean in lower RPMs, even though our fuel flow rate has been adjusted based on the exact percent difference. The scale for common injector sizes used is 5% for 440-450cc, 4%, 390cc, 3% for 310cc.. then subtract 1 percent per 500 RPM increase. This will give us are starting point. For a boosted application, running stoichiometric is dangerous because of the high volume of air. To "play it safe", you want to run a bit on the stoich/rich side, so we increase fuel flow by 1% per 1000 rpms, trying not to top out a 5% overall increase. Why 5%? ..because your fuel maps are still increasing in pulse duration. So you're increasing pulse duration, and percentage
of flow rate at the same time. You'll get rich, very quickly. If you have VTEC, enrich by 1% more over VTEC VTEC crossover.
So, lets apply everything we've learned, and come up with base settings for 450cc injectors.

1) 240/450 = 0.53
2) 0.53 - 1 = -0.46
3) -0.46 * 100 = -46

So we have a 46% difference, we add our 5% for injector latency compensation, which leaves us with these settings:

1000 - 40%
1500 - 40%
2000 - 39%
3000 - 38%
4000 - 37%
--- VTEC set to 4400 RPMs ---
5000 - 35%
6000 - 34%
7000 - 34%
8000 - 34%

Application of these ideals will find your AFC Hack producing the smooth, safe, reliable power.

2-5) What is the maximum amount of boost I can run using the "AFC Hack"?
Due to the scaling of MAP sensor signal, and maximum read boost amount by the MAP sensor, ~10psi is obtainable. Some of boast numbers reaching ~12psi. Other limitations apply, please refer to 2-2 for more information.

2-6) Will the "AFC Hack" in conjunction with my X size injectors effect my idle?
Yes. However, if the proper settings are applied, and a reliable AFC is used, your idle should be smooth as stock. Refer to 2-4 for information on how to calculate settings.


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