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-   -   SAFC/VAFC Hack (https://www.homemadeturbo.com/engine-management-10/safc-vafc-hack-2311/)

Semnos 02-27-2003 06:13 PM

SAFC/VAFC Hack
 
"The afc hack you use a MAP limiter, and then step up from a negative value for fuel with the afc (i was stepping up to around +5%) once the car starts to boost.

So i was thinking, isnt a limited MAP (with a missing link check valve whatever) and the afc stepped all the way to +5% the same as an unlimited map with the same boost? (that is if i got the damn thing tuned right)

So i pulled into a gas station and modded the fuel system. I removed the missing link so i had an unlimited map. I set my AFC at -40% from 1000rpms to 8000rpms so it would keep it no matter what boost level i was running."

As I can figure out this guy has the AFC HAck with the extra Boost sensor and that is hooked to the TPS and he has no missinglink on the stock map(ECU not throwing CEL?)
And put the AFC at -40% from 1000 rpms to 8000 rpms?

I have a headache .... is this right how I said it?

scttydb411 02-27-2003 06:21 PM

Re:SAFC/VAFC Hack
 
the "hack" you use larger injectors (typically 440 or 450) and trim back the fuel with the afc. so what you said was right at the end if you are using larger injectors. if you were using your stock injectors you wouldn't have enough fuel. the larger injectors with the same pulse as stock would be lots of fuel and that's why you trim it back and it also trims back the voltage the map sees as boost. anybody correct me if i'm wrong.

Semnos 02-27-2003 06:32 PM

Re:SAFC/VAFC Hack
 
I read it again and again.. I got it now I think..looking at the parts list.
He just has the DSM injectors and the walbro fuel pump he doesn't have the extra boost sensor as they show at the DSM site about teh AFC hack. So the output signal of the stock map goes to the AFC? and to the ECU? but without a missinglink isn't the ECU throwing CEL? cause the Map will read more than the 1 bar(atmosphere).
Help me out :(

scttydb411 02-27-2003 06:47 PM

Re:SAFC/VAFC Hack
 
the negative setting also subtracts the voltage going to/from sensor/ecu. even though there is more boost you are tricking it into thinking the boost is the same. that's why you have to use larger injectors.

Semnos 02-28-2003 02:30 AM

Re:SAFC/VAFC Hack
 
ahaaa thanx alot
Got it


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