dwilson

Just wanted to check up on how the afc hack is holding up for all of u. I am fixing to use the hack and just wanted to check in. Also has anyone ever dynoed their car with this hack in place? If so what was the results.

Tuan

When mentioning AFC HACK, if I recall correctly , it's when you just hook up the AFC normally, and just run -40 across the fuel maps, OR the AFC where you switch your map sensor wire to the TPS sensor? Just curious, cause I get confused when people mention AFC hack, which one are they talking about? Becuase I remember post that mentioned to "just hook it normally like how the APEX instructions says, and then -40 across." Thanks

Mr. Vapor

yea, could someone elaborate on the "hack"

technine

I am interested in seeing who is actually using it and how it came out.

DSF

I've been running with the AFC "hack" for over a month. No news to report really, which I guess is a good thing. It works as it should. No dyno/track figures, yet.

http://www.geocities.com/snailpowere...x_dx/album.htm



[Modified by DSF, 1:37 PM 5/24/2002]

shadowdawn

I have the afc but its still un-tuned, saving for dyno time. AFC hack just means you installed the AFC normally. There is a method involving taking dsm 450's and putting them in then doing -40% across the board, theres a link to that on these boards if you search...

VTC_CiViC

That pretty much IS the method. Install the injectors, turn the key to 'ON' (don't start the car) and set the AFC for -45% for idle, -40% the rest of the way and start the bastard..


[Modified by VTC_CiViC, 2:04 PM 5/24/2002]

Hammett

does the method only work with 440cc injectors?


[Modified by Hammett, 7:42 PM 5/24/2002]

5 Liter Eater

Let me first say that the AFC hack is the shiznat. There are two versions and both involve using 450cc injectors, a VAFC or SAFC and removal of any rising rate regulator.

The first substituted an unlimited MAP signal to the TPS input of the AFC (VAFC or SAFC). This allowed you to use the narrow and wide throttle settings for vacuum and boost tuning respectively. You set the narrow throttle and wide throttle wherever your MAP is at atmospheric, usually ~70%. This method still requires you to limit the MAP signal somehow so the ECU doesnt throw a CEL. I'm not sure what the settings would be set to on the MAP to TPS afc hack. I think DBMAN96 came up with this idea but I may be wrong. Whoever it was caused Liam to use it and he eventually thought of the -40% hack. Se below:

The second hack, referred to as the -40% AFC hack seems to be the current best approach to AFC hacking. First you remove any FMU/RRR you have as in the first hack but now you also remove any MAP limiting devices (check valves/blue box/black box/etc.) and let the ECU see boost. You hook up the VAFC per the instructions, no substituting signal wires. Then you set the all the narrow and wide throttle fuel corrections to -40%. Set your narrow and wide throttle points to wherever you want, I have mine at 25% and 75%. By taking 40% out of the MAP signal you are reducing the voltage enough so that the ECU only thinks you are at atmospheric when you are at full boost. The MAP signal is 0V at full vacuum and 4.5V at 1 BAR (~14 PSI). If the signal reads more than ~3V the ECU trips the MAP CEL#3. By reducing the signal by 40% you reduce the voltage enough to prevent a CEL. Basically you are using the stock fuel maps in the ECU, you're just moving the whole thing over. So at full boost WOT the ECU thinks you are at atmospheric pressure WOT with stock injectors which it would let open a lot. It doesn't know you have 450cc injectors and it just so happens that 450 injectors wide open is just about right to support ~8-10 PSI comfortably st stock fuel pressure. Keep in mind that you are taking -40% out of the MAP signal, you're not running a 450cc injector at 60% duty cycle or anything. I have actually set my narrow throttle to -32% based on my "cruising A/F calibration method" and my wide to ~-40% +- 3-5% in the wide map based on the dyno. photos.yahoo.com/winters_bill

I have only tried the -40% hack and I love it. Idle is like stock and off boost driving is very snappy, not like when I had 310's and a Cartech. Boost is great, but keep in mind that if you are well tuned for WOT with your current setup then you're not going to gain any ponies by using this method, it's more for drivability. Best of all, I sold my 310's for ~$200 I think and I still have my Cartech but that's worth another $100-125 and I got a used VAFC for $150 (missing the extension cable which I had to fabricate) and some DSM 450's and resistors for $55 so I actually made money on the deal!

My "A/F Calibration Method" basically wires in a toggle switch in between the O2 signal and the ECU so I can cut the signal back to the ECU to disable closed loop operation (A/F flips back and forth lean to rich). So I do an ECU reset, go out on the highway late at night and set my cruise control and flip the switch. The A/F starts showing how close you are to stoich at that given manifold pressure (usually 10-20" Hg). I found that -40% was too lean so I went to the given point on my VAFC (3000 RPMs) and start taking less and less out until the A/F comes into the stoich area, which was -32% for me. Then I set my entire narrow throttle curve to that percentage. For more info on this search on "calibrating a modified fuel system"

John_at_J&S

The new J&S 1 channel/2 channel Ultra SafeGuard unit has the capability to modify the MAP voltage, if programmed at the factory. This is besides the MAP Limiter function.

This is what Ben from importparts.com was hinting at a couple weeks ago.

The standard AFC hack lets you run bigger injectors, but it has the disadvantage of unintentionally advancing the timing, since the ECU thinks the MAP is less than it really is.

Since the SafeGuard is already a timing controller, we will be able to prevent the unintended timing advance while allowing larger injectors.

VTC_CiViC

I used it with 440's, others with their 450's no problem.. I'd make sure i'm at least 440cc though.

liam821

Im still running it on my honda..and it runs great! We also got it running on my friends b20/vtec + turbo.

Here is his setup, b20/vtec (buit) b16a mugen ecu using the afc hack. We had to set is fuel at -25% because the b20 is a thirsty beast. We are only running 5psi of boost and its awesome....talk about torque and tons of power. We are planning on rasing the fuel pressure and turning down the afc so we can run some more boost.


It rocks

liam

5 Liter Eater

I don't see this as a disadvantage, but rather an advantage. At 9.6 PSI (per the VAFC) I'm taking out -40% which may be more than I need to take out in order to prevent a CEL so perhaps the ECU is seeing slightly less than atmoshperic pressure so it may be adding some timing but I hear no detonation but I'll agree that this is a slight disadvantage.

The advantage is that while out of boost where retarding the timing hurts the most, the ECU is adding even more timing since it thinks there is a lot of vacuum.

But it seems like the new Safegaurd would suffer from the same disadvantages as the AFC hack since it's also changing the MAP signal to allow larger injectors correct? Or does the Safegaurd compensate for the timing issues since it can control the timing so granularly?


[Modified by 5 Liter Eater, 3:25 PM 5/25/2002]

Pissoff

uh yeah

info here

http://www.thedropshop.tv/vafc.htm


[Modified by Usdm ED9, 12:51 PM 5/31/2002]

NeXtLeVeL_TyPe_R

can you do this with 370's ???

Finest

I'm pretty sure. But you probably won't need to cut -40%...probably -30% or more. I've only seen this work for 440/450's though.

NeXtLeVeL_TyPe_R

At what psi would your idle fuel pressure be around to be able to get that adjustment ????

Because this is the problem i am having (i actually just posted in tech about it)

I cannot lower the fuel pressure lower then 45-50.
This is a problem because i need to idle the car and tune it with 370's

With the fuel pressure that high the car idles like crap and is way too rich across the board. I cant even take any more fuel away...it is at the piont where i am -50% and i am still really rich like .9 o2 voltage

I am running a walbro intank, 6:1 FMU an missing link.

Is there any way to get around this or to lower the pressure???

I took off the FMU and still had the problem off not being able to lower the fuel pressure or have adjust range to lean it out any more.

Should i take of the missing link too??

I am so lost - sorry for all the questions i am just trying to make this turbo kit somewhat reliable- so far its not and i am getting really frustrated- I appericate any help

If anyone local can help me that be great - i will treat for dinner and beer lots of beer



[Modified by NeXtLeVeL_TyPe_R, 4:13 PM 5/31/2002]

5 Liter Eater

At what psi would your idle fuel pressure be around to be able to get that adjustment ????

Because this is the problem i am having (i actually just posted in tech about it)

I cannot lower the fuel pressure lower then 45-50.
This is a problem because i need to idle the car and tune it with 370's

With the fuel pressure that high the car idles like crap and is way too rich across the board. I cant even take any more fuel away...it is at the piont where i am -50% and i am still really rich like .9 o2 voltage

I am running a walbro intank, 6:1 FMU an missing link.

Is there any way to get around this or to lower the pressure???

Drill out the FPR ala http://www.theoldone.com/articles/regulator/. you will need an adjustable clamp on FPR like the B&M or the Vortech. Your high volume in tank pump is overwhelming the stock FPR. With the AFC hack you should run stock fuel pressures (42 vac/52 static for a GSR)

I took off the FMU and still had the problem off not being able to lower the fuel pressure or have adjust range to lean it out any more.

Should i take of the missing link too??

Yes. To do the AFC hack right you don't limit the MAP signal. You let the ECU see boost. No FMU either.

CovertFI

you need to lower your fuel pressure with a fuel pressure reg. you know the one on your fuel rail. you can get the b&m one and drill a tiny hole in the plate. you would have to see a pic to understand what i am talking about. or just buy an aem fpr. that will lower your pressure.

NeXtLeVeL_TyPe_R

I have a B&M and it will not lower enough. I am going to try the website idea today...thanks so much for the help guys i will let you know how it turns out

5 Liter Eater

The pics you need are on this pagehttp://www.theoldone.com/articles/regulator/. They will allow you to get your fuel pressures back down to stock although with 370's instead of 450's I'd think 50/60 instead of 42/52 would be good assuming all other AFC hacking prereqs are met.

Again, there is really no reason for a high volume pump w/ the AFC hack, just as with the Hondata you can use your stock pump because you're not seeing fuel pressures over stock so to quickly remedy the problem you could put your stock pump back in.

NeXtLeVeL_TyPe_R

For that mod do you drill threw just till you hit the first wall or till you go all the way threw. I got threw the intial wall and hit another wall like 1-2mm in.

I tried it and it adjust lower but not low enough...
Should i go threw both walls or make the intail hole bigger

I am at 50psi at idle and still really rich across the board

Thanks for any suggestions


[Modified by NeXtLeVeL_TyPe_R, 1:43 AM 6/1/2002]

NeXtLeVeL_TyPe_R

Well I got it to work i can lower and raise the fuel pressure witihin a good range.

But for some reason i am still running super rich....
The lowest fuel psi i can go now is 30 which iu would think would be good enough.
I cant go any leaner on my AFC -- I dont know whats up

Now i am running Walbro Intank and 370cc injectors --- NO FMU/NO MISSING LINK

Thanks for any help ahead of time


[Modified by NeXtLeVeL_TyPe_R, 5:44 PM 6/2/2002]

TriK

ttt... I want to know!

CalvitoSol

What model year are the DSM injectors that are needed for this hack? do the injectors plug right in or do i need a new harness? Also, someone mentioned that you also need a resistor box from the 88-91 hondas. Just found out about this amazing hack and am really interested.