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Old 03-13-2019, 10:02 PM   #1
hise23
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Default 2008 normal AFR

so i just replaced my intake manifold gaskets because when cold it was at 17+ afr idle. My cars stock I reset my ecu and i was wondering what normal afr. When i floor it and hit target boost at any rpm below 3800-3900 my afr is in the 13s sometimes drops to high 12s. then when i get above 4k it instantly drops to 11 afr is this normal? Im new to wrxs so i appreciate any help
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Old 03-13-2019, 10:43 PM   #2
hise23
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also my warm idle is at 14.2 to 14.5 its never at 14.7 when warmed up at idle for some reason
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Old 03-13-2019, 10:45 PM   #3
Exit 37
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also my warm idle is at 14.2 to 14.5 its never at 14.7 when warmed up at idle for some reason
Are you reading from a gauge or AccessPort?
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Old 03-13-2019, 10:57 PM   #4
hise23
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im reading from the stock o2 sensor
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Old 03-13-2019, 11:23 PM   #5
hise23
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the car dosent run rough but i just wanted to make sure my afrs were safe. my friend with a 2002 told me that my afr was way to lean. but
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Old 03-14-2019, 08:24 AM   #6
Exit 37
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Okay so are you reading 14.2-14.5 from a gauge like a AEM or ProSport AFR gauge or are you reading that from a Cobb AccessPort? As for O2 sensor, your car probably has two so saying "stock o2 sensor" still doesn't mean much.
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Old 03-14-2019, 12:27 PM   #7
hise23
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Accessoort
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Old 03-15-2019, 10:40 AM   #8
Exit 37
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You'll have slight variances at idle. As for your boost AFR, what are your mods and tune?
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Old 03-15-2019, 11:56 AM   #9
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Quote:
Originally Posted by hise23 View Post
the car dosent run rough but i just wanted to make sure my afrs were safe. my friend with a 2002 told me that my afr was way to lean. but
is you car throwing a lean code, if not i wouldnt worry about it
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Old 03-15-2019, 01:11 PM   #10
hise23
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no mods all stock. i was just asking cause i have 2 friends with wrxs. one with a 2002 with stage 1 and one with a 2007 with stage 2 plus and their afr is way different then mine. I thought maybe mines leaner cause it passes California emissions.
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Old 03-15-2019, 03:06 PM   #11
Exit 37
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You have an AccessPort but you're all stock? Please explain.

Comparing to your two friends' cars is apples to oranges because they're not on the stock tune, so they'll have a different AFR compared to you. I can't remember what stock AFR is under full boost since I haven't been stock in years, but it's probably something like 10. Your idle and cruise AFR should ideally be in the 14 range, with 14.7 being stoich. On my e-tune, my idle/cruise AFR is anywhere between 14.59-14.8, boost AFR settles at 11.03 til redline. Your initial AFR under boost is a bit lean which can cause knock leading to more problems. You should probably post a WOT log to see the full picture of what's happening with your car. It's also worth noting that boosting at low RPM like that is asking for ring land failure. Things to log:

AF learning 1
AF Correction 1
Boost (could be called manifold relative pressure) AF
Calculated Load
COOLANT TEMP
Dyn adv. Mult. (on some cars)
Dynamic ADV.
Dynamic ADV Learn
Feed back knock (sometimes called Fine knock learn)
Ignition timing
Injector Duty Cycle
INTAKE TEMP
MAF
MAF Voltage
RPM
THROTTLE POSITION
Sense 1 Ratio (AFR)

So to recap, your idle/cruise AFR should be in the 14 range, your boost AFR should be 10-11, pull logs to review, and high load-low RPM can cause ring land failure.

Last edited by Exit 37; 03-16-2019 at 01:32 PM.
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Old 03-16-2019, 07:43 PM   #12
hise23
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I have stock tune was using friends accesport to read afrs because we fixed intake manifold leak and wanted to see if it was fixed
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