Afc Hack

[truth?]

If you are going to post info like this you need to post your source. - comutek

written by: Pollito of www.turbod16.com
http://pollito.no-ip.com/turbod16/viewtopic.php?t=2118

What is the AFC hack?

It is a method of fuel management that uses Apexi's AFC fuel controller and larger injectors of your choosing.

Why is it so widely discussed?

It it one of the cheapest tunable fuel management systems for forced induction use.

So, how does it work?

Well, with a forced induction setup we obviously want to supply more fuel while in boost than stock would allow us. This is where the AFC comes in. The unit allows you to richen or lean your fuel +/- 50% The unit does this by interceoting your MAP signal and modifies it to trick your ECU into thinking you are getting more or less air than you actually are. So that sounds great. I'll go pick up an AFC and use it on my stock fuel setup. Well, thiis is where the problem is and why the "hack" was thought up. If you just richen up your boosted car using the stock injectors, your MAP sesnor will read boost and throw your ECU into limp mode. Why does the ECU go into limp mode? Well, your ecu does not have fuel tables for anything above vacuum, so it shits a brick. Wow that sucks huh? This is where we buy larger injectors. Most people go for 350-550cc injectors. Of those people the most popular are the dsm 450s and the RC 440s. These are the most popular because they offer the best idle on stock fuel maps but still allow you to boost 8-12 psi before going into limp mode.

How do I set the AFC for larger injectors?

We are actually going to lean things out with the AFC. If we just stick in larger injectors the car won't even run. It would be ungodly rich running on the stock fuel map. The ECU has no idea there are 100% larger injectors sitting in the rail and is still sending the same injector pulses. So how much should you lean out? Let's say you have 240cc injectors stock (most civics) and you want to idle a set of 440cc injectors as if they were stock. With a little math we see this:

240/440 = 54%/100%

So we need to take 46% of the fuel away from 440cc injectors to run them like 240cc injectors. Now this is not a perfect conversion because there are more factors than this, but it gives you a ballpark # to start with. As for settings under boost that varies a lot, but under WOT and full boost of 8-12psi a setting of -35 to -30 on the AFC should keep things good and rich.

[dubcac]

I'm not a big fan of the AFC hack. Everyone I know that has used it, the car has run like crap. It's a great idea in principle, and sometimes works great. I also suggest that anyone running boost, especially something like an AFC hack, get it tuned on a dyno by someone who knows their shit.

[imported_Francisco]

My friends car with the AFC hack runs like crap..It just runs 12.6 at the track and its a SOHC coupe.

A lot of ppl that will talk bad about AFC hack its because they have heard other ppl say it and havent actually tried it. I know that a complete fuel management sistem will be way better but its not that "crappy" as a lot of ppl makes it seem to be.

Its better than nothing..

Granted..if you are going to run 20+PSI then the AFC hack its not the best thing to rely on, although i do know ppl with 20PSI of boost running on just the AFC hack, but for low and mild boost application it is a very good alternative at an affordable price.

I know atleast 4 guys where i live that runs the AFC hack, all of them are SOHC motors and the slower of them runs 13.0 at the 1/4 mile track. All of them are between 15 and 20 PSI and have been running the AFC for more than a year..

Ill be the 5th from my group of friends to be running AFC and another friend the 6th.

[dubcac]

Everyone that I personally know that has run it, has run extremely rich for some reason...even under decent amounts of boost, and dyno tunes. It does work great for some people though, I didn't say that it sucked and was horrible...I'm just not going to run it if I go boosted.

[imported_Francisco]

Well running rich on boost is not a bad thing..... it just a tunning issue..Its better to have more fuel than lack of it..Thats when turbos blow up , cause of lack of fuel management.

I can understand when it gets to the point that even the AFC will not be enough and them some other kind of bigger/better fuel management is needed..but running richer wont kill your setup.

12.1 - 11.8 A/F line is what ppl usually run with boost,almost a straight line..Isnt that running rich?

[imported_Francisco]

BTW. im not saying ure hating on the AFC..im not refering to you ,its just a general comment of what the majority seems to think.

[Smooth_Imports]

Originally posted by Francisco@Apr 6 2004, 12:32 PM
Well running rich on boost is not a bad thing..... it just a tunning issue..Its better to have more fuel than lack of it..Thats when turbos blow up , cause of lack of fuel management.

No thats when motors blow up. Lack of fuel will do nothing to the turbo, Lack of oil / water blows turbos. depending on the cooling methods. Bu your right it's better to run rich then lean. But running rich isn't a great thing either, If you wasting fuel your wasting power.

[imported_Francisco]

Originally posted by Smooth_Imports+Apr 6 2004, 01:12 PM--><div class='quotetop'>QUOTE(Smooth_Imports @ Apr 6 2004, 01:12 PM)</div>

No thats when motors blow up. Lack of fuel will do nothing to the turbo, Lack of oil / water blows turbos. depending on the cooling methods. Bu your right it's better to run rich then lean. But running rich isn't a great thing either, If you wasting fuel your wasting power.[/b]

Well i shouldnt have said Turbo blow up..i should have said pistons...thats the most common thing ppl blow on a turbo setup and its due cause of lack of fuel at high rpms..
Usually piston #3 goes first..

My bad about that.

[dubcac]

Piston #3 goes first because the OEM honda intake manifolds are biased to it, and flow more air there than the other cylinders. Running rich is ok to a point. However, they were running so poorly that the car was sputtering constantly, and fouling plugs left and right. I don't care if most people run rich instead of stoichiometric...just cause they do it doesn't mean it's a correct tune.