wat is AFC arr

[kiran84]

hey all the mafia out there....................

wat is AFC actually for arr...........

 

[L2TurboFool]

Air Flow Control?

 

[flamefox850]

air fuel convertor. for apexi s-afc..just add super in front :D

 

[L2TurboFool]

i'm very curious...what does it actually "convert"??haha

 

[flamefox850]

it convert the signal from map sensor to ecu lah.
if map sensor read 0.8bar then u add +20% on safc then gives at around 0.96bar...then ecu order the injector to inject more fuel to support 0.96bar of what it sees from safc

the figure is not accurate..only my assumption

 

[pang]

good info flamefox...

 

[aiM]

just say it we can tune the air and fuel like carb. because fuel injector cant be tune like carb without a proper tools. or in the other words, save fuel, more power, bla bla bla.. see who setting lah hehehe

 

[drexchan]

Originally posted by flamefox850@Feb 8 2005, 23:35
it convert the signal from map sensor to ecu lah.
if map sensor read 0.8bar then u add +20% on safc then gives at around 0.96bar...then ecu order the injector to inject more fuel to support 0.96bar of what it sees from safc

then wouldn't the O2 sensor sense the rich misture and re-direct the ECU to cut the fuel (by increasing the duty cycle of the injectors) during close-loop operation?

if so, then AFC is useful only during ecceleration but not cruising.

correct me if i am wrong.

Let's assume that i am right. Wouldn't an adjustable FPR (at much lower price) do the same job?

 

[flamefox850]

hmm O2 sensor or ext temp sensor gives signal to ecu..when got rich signal..it told ecu to lean it...but it only TRIM it i think..trim then only little precentage only. so, if u adjust the safc into too rich..then O2 sensor cannot told the ecu to lean it too much until it going into STOICH mode. this is what i think...expert pls gives out comment

if the O2 can really2 help ecu to get stoich mode..then no need safc or other fuel management right ? B)

p/s: adj fuel regulator only adjust the fuel pressure..and fuel pressure increase as boost increase too...so if u adjust so high..u got rich mode in all rpm..be it at idle or high rpm or high boost

 

[drexchan]

Originally posted by flamefox850@Feb 15 2005, 00:17
hmm O2 sensor or ext temp sensor gives signal to ecu..when got rich signal..it told ecu to lean it...but it only TRIM it i think..trim then only little precentage only. so, if u adjust the safc into too rich..then O2 sensor cannot told the ecu to lean it too much until it going into STOICH mode. this is what i think...expert pls gives out comment

if the O2 can really2 help ecu to get stoich mode..then no need safc or other fuel management right ? B)

p/s: adj fuel regulator only adjust the fuel pressure..and fuel pressure increase as boost increase too...so if u adjust so high..u got rich mode in all rpm..be it at idle or high rpm or high boost

normally the compensation rate from the O2 sensor is about 10%. Meaning the ECU is able to increase or decease the fuel feed by 10% from the MAP setting. If AFC adjusted it too high then the ECU will not be able to adjust the feed.

A-FPR.. hmm yes you are right. But remember there is this little O2 sensor that do the trick. At idling or cruising at part throttle, the engine is governed by close-loop operation. So no worries or lean or rich IF the fuel pressure isn't too high. Only when the engine is eccelerating, the mixture will become rich.

Alternatively, one may try rising rate FPR (RRFPR) or sometimes called FMS (fuel management system).

 

[flamefox850]

yerp..u r correct :)

 

[gunter]

Good gadget to have.. it actually gave me good FC.. and increased hp's.. but need to be coupled with other mods to gain full advantage of this device.. cheers..

 

[taqu]

AFC works by intercepting airflow signal from engine, modifies it, then sends the modified signal to ECU. ECU, upon seeing the modified airflow signal, will "think" actual airflow is higher or lower, then it will lookup into different location inside its fuel map. I guess Proton or most other stock ECU have airflow data lookup values for upto 50% higher than regular fuelling requirement, that's why AFC works. Go above 50%, the stock ECU might go crazy coz those "altered" airflow signal may no longer exists inside its fuel map. So AFC is a good solution if ur modifications doesn't require u to increase fuel over 40%.

I wonder if someone can do this thing the other way around, instead of modifying airflow signal from AFM/MAF/MAP sensor to ECU, why not modify injector timing from ECU to injector? That could give much wider tuning range than 50%.

 

[TE27levin]

but the stupid S-AFC will bring dis advantage to 2 bar MAP sensored car.

when ur turbo boost 0.8bar u increase SAFC to 20% richer then ecu will cut off the fuel supply because it reach the 1bar boost cut. LOL!!!

 

[stroker_kit]

thats when an FCD(fuel cut defencer) comes in handy... mods just doesnt come cheap nowadays... :(

 

[taqu]

What about substituting that 2 bar MAP sensor with a 3 bar MAP sensor (so that ECU will read lower boost than actual boost), then connect that SAFC to read MAP signal instead of TPS signal, then re-tune the SAFC? Can this method overcome that boost cut? Or am I just shooting stupid idea :lol:

 

[flamefox850]

Originally posted by TE27levin@Feb 15 2005, 17:03
but the stupid S-AFC will bring dis advantage to 2 bar MAP sensored car.

when ur turbo boost 0.8bar u increase SAFC to 20% richer then ecu will cut off the fuel supply because it reach the 1bar boost cut. LOL!!!

hahahaha this is what happen to me last time when using L2 injector on 882t engine :lol:

taqu...u r correct. change MAP sensor from 2 bar to 3bar will ensure u will never get boost cut until ur boost hit 2bar boost ! BUT..if ur ecu is stock..u will running very2 lean compare when u running on ur stock 2 bar MAP sensor
this concept is the same concept used by FCD actually.

it goes like this...ur ECU will cut fuel if it got 5volt signal from MAP sensor. if using 2bar MAP sensor..0.9bar boost will hit almost 4.8volt but when using 3bar MAP sensor with same ECU..1.8bar will transfer 4.8volt also.

but what happen if using 3bar MAP sensor and running only 0.9bar...i think MAP sensor will send signal not more than 3volt and u will running lean if other part is still stock.

what fcd or other modded ecu does is preventing the ecu from getting 5volt signal to prevent boost cut. so, if usually 1.0bar get 5volt signal..it will ensure that 1.3bar boost only send 4.9volt, 1.5bar boost also 4.9volt, even 1.8bar boost also 4.9volt. and u will end up running leaner and leaner when u boost higher. that's why u have to get bigger injector as well

correct me if i was wrong dude

 

[taqu]

flamefox850, how are ur GSR injectors? Running fine now? B)

So FCD prevents boost cut by altering the MAP signal, but it cannot retune air-fuel ratio right? That's why I thought about that MAP sensor mod to lower the MAP voltage output and then using SAFC to retune.

 

[flamefox850]

my injector ? just like that la...hard to tune until i put the adj. fuel reg. now out of money lor adeh. clutch not pasang yet. hard to tune when ur car is not complete pasang with all the necessary gadgets ..damn

hmm if the car use MAP sensor only..then if u change it to 3bar MAP sensor and try to get richer state by adjusting the safc..it think u just playing around. let say u set boost at 0.9bar and change MAP sensor to 3bar one...then automatically ur ECU sees very2 low boost and decide to inject less fuel and u will running lean. u adjust the safc to get richer or stoich state...and u cheat the ecu that u got high boost (eg. 1.6bar). after all..when boost a bit higher than too much richer on safc..u will encounter boost cut again.
so better get programmable ecu or a bigger injector pair with safc

 

[TE27levin]

that why i swap to microtech ecu now.. hahaha.. stock ecu wont work if looking for more power.