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Old 09-27-2012, 05:38 PM   #1
zpl2
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Default Afr tune possible 01 forester

Hey I just got a 2001 forester n/a and was told there was an afr adjusting tune on it. My question is there a way to just adjust afr with no ecu reprogramming. If im not mistaken an 01 forester with no piggy back or ecu swap are not reprogrammable.
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Old 09-28-2012, 03:12 AM   #2
68Cadillac
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Quote:
Originally Posted by zpl2 View Post
My question is there a way to just adjust afr with no ecu reprogramming.
You could intercept the voltage signal from the MAF sensor to the ECU, rescale it, then send a different voltage to the ECU.
You could install different size injectors and not tell the ECU.
You could install a different diameter tube for the MAF sensor to sit in and not tell the ECU.
You could change the fuel pressure and not tell the ECU.

All four seem like really bad hacks to me. Would seem easier just to do it in the ECU.
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Old 09-28-2012, 03:16 AM   #3
eg33GC
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emanage or pp6
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Old 09-29-2012, 01:38 AM   #4
zpl2
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The system is actually map so does the voltage thing apply and if so how could I change it back.
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Old 10-03-2012, 02:02 PM   #5
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Bump!!
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Old 10-09-2012, 09:26 PM   #6
mikeydrives1
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As a forester owner i can almost assure you theres no way to tune the stock ECU of that year. You would have to utilize some sort of Apexi SAFC unit and get a tuner to play around with it on the dyno.
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Old 10-14-2012, 12:14 AM   #7
zpl2
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Okay thankyou is fuel restricting possible to "tune" the afr lean without a computer or are you saying there is no way to tune them at all!
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Old 10-14-2012, 06:50 PM   #8
mikeydrives1
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What im saying is, yes your ECU cannot be reprogrammed at all, unlike newer cars. The onlder ones just do not operate that way, as far as im aware of.

Like i said, a standalone SAFC unit or expensive piggyback is your only option. But to be hoenst, why do you want to accomplish this? What are you gaining from this? Even a modified motor doesnt need a AFR adjustment.

I can tell you right now... on my stock forester motor (old) , I had a lightweight crank pulley, decked the block for slightly higher compression when i had the heads off to get that headgaskets done, had a Cold air Intake, borla header and catback exhaust and the ECU ran the car beautifully with 12.5 to 13.0 AFR's (according to the Eugo) during wide open throttle pulls, and not a check engine light in sight. The stock ECU is plenty capable of making the adjustments.

However, if you had built the motor to high compression (I.E 12:5:1 ) , built the heads with stiffer springs/valves and bigger camshafts, then YES, you would need a piggyback or SAFC to make the proper adjustments for pulls
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Old 10-15-2012, 09:10 AM   #9
quazimoto
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And just to add as said above,any adjustment in closedloop fueling will be learned around in a matter of days due to the O2 sensor feedback and fueling trims. The ECU wants to see 14.7:1 in cloosedloop. The only adjsutment you will really have is in Openloop.
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