OK .. someone explain to me what they are all about. I have one fitted to my car. It was there when I bought it.

 

Am I right to say that it fools the ECU into providing more fuel to the injectors?

 

If it does, what good is it when you have standard injectors? I haven't checked what injectors I have at the moment but I would like to know the benefits using standard injectors. Surely they max out at a standard rate anyway. I am rather confused on the use of the AFC and would like to know more...

 

Also, if you do have an AFC I presume it is a good idea to have a gauge to indicate if you are running too rich or lean.

 

Can someone give me the lowdown on AFC's ...

 

Cheers .. confused ....

 

 

Chris

Anyone? .. I know, patience isn't one of my virtues!

C'mon guys if you not too busy poking your ladyboys ...surely someone can answer this question?

 

Clarkey?

Its generally a dodgy bolt on mod that puts more fuel in than air. I've no idea why anyone would want to do this as your car could start detting.

 

Why put more fuel in than there is air going in? to up the timing a little, ok safe to do a LITTLE but still not good IMHO. My idea is, if your fooling the car into thinking there is more fuel than there is air not good, its false economy, your car cant really suck / boost any more air than it is so then why bother? Some people do it on NA's, the generally beleive more fuel = car demanding more air, that it will need, but just cause you put more fuel in it doesnt mean your car will run to suck more air in. (im a wee bit pissed hope that kinda makes sense lol!)

 

Sometimes increasing timing is ok as long as you run high octane fuel, but generaly, I would say a no no.

oh yeh didnt see the AFC, (even though thread is called that! but be nice I am drunk and tired!) if thats what you are on about as the fuel thingy, then you really need to get it set by someone who knows what they are doing and on the rollers to get it accurate.

 

It controlls fuel and air mixture, so you can have the optimum mix at any point in the rev range.

 

Best to get it done properly mate.

 

You can fiddle with it at home, the worst that can happen is it runs worse, listen for funny noises lol. I would say as a rule set it to 0 or leave as it is now and then get set up on the rollers.

 

Cheers

 

Steve

hi just got an apexi super-afc2 fitted at thor last week. after a rolling-road tune (which scared the bejeesus out of me as i thought either the engine would explode or the shop roof would fall on me!) it gained about 10bhp but the guy said the fuelling was good before anyway so there werent much gains to be had (and ZERO detting ;) )

i bought it really to try and correct my slight stall problem after my bovs were installed but it hasnt :mad: :cry: . it DOES look good on the dash tho. im posting piccies up in another thread shortly.

As Stevo says, its a dodgy, crude bolt on that fiddles with the MAF signal to adjust the fuelling at different RPM points.

 

3 big problems with these:

 

1) It makes no account for engine load, so if you put 5% more signal on at full load on the dyno, you might then run mega rich in the mid range and loose loads of power / drivability.

2) The MAF signal isn't used directly to calculate pulsewidth, it just 'points' to a section of the map. This means that you still can't add more fuel than the richest load point on the map at the given RPM anyway.

3) The MAF signal also tells the timing maps where to access, so you mess the timing up too. At best, you'll retard it a bit and loose power (presuming you're trying to ADD fuel) at worst, you'll retard it a lot and get the EGR temps huge with possible exhaust valve damage.

Thanks guys. I have set my AFC to 0 because I didn't wan't to mess with it TBH.

 

John do you remember that chip I had in my car before your special? I remember looking at the maps with you and at the time you said it was a very aggressive set up.

 

Thinking really of ditching the AFC.

 

Would it be possible to come up and see you John at some point so you could have a look at what is going on with the car? It runs brilliantly with no det but would like to know if someone has messed with the timing previously when I had the original agressive chip and maybe it needs to be sorted. I am running slightly rich judging by the black deposits in the exhausts.

Sure, drop me a line and we'll sort it out.

Cheers

I have an S-AFC 1 on both my cars. They are only useful when you have altered the air flow into the vehicle (induction kit or the like). On some vehicles, adding an induction kit changes the air flow beyond the constraints of the original ECU. Often the ECU then works the injectors overload....as a default setting hence the engine will run rich. The results of adding an AFC are dependant on other mods and the vehicle you are installing on. Power gains can be 0 ....sometimes they can be very good...

One thing I would advise is to have it setup on a rolling road.

Apexi can supply default settings for your AFC in certain applications (such as AFC with an APEXI induction kit on car X use these settings.......xxxxx). I followed these settings for an Altezza RS200 and gained 3BHP, took it to a rolling road and they gained 12BHP.

Just my 2pence worth....hope it helps.

Cheers fellas ..

 

John I will drop you a line mate ...

 

Chris