Not sure if problem or not- Fuel/Air Ratio? - Subaru WRX Forum
 
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post #1 of 5 Old 04-10-2003, 06:25 PM Thread Starter
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Not sure if problem or not- Fuel/Air Ratio?

Ok, my car has some mods... and seems the harder i drive on it, the less "ok" the engine sounds... it just sounds, dirty or tired or something.

My issue is this... Hi flow (4 into 1) engine header, Catless uppipe, TurboXS turbo-back exhaust (no cats), and racing style CAI (w/drycharger to keep water out)....

Is this going to be too much increased air flow for the stock ECU? Its basically a straight-thru exhaust system.
Or will the ECU compensate with extra fuel for it? So when i'm driving the car REAL hard, is the engine going to burn too lean and damage it? What about just average driving? I have, of course, check engine lights because of no cats and also i no longer have that sensor that goes into the uppipe (looks like a temparature probe or something)... The car goes real fast and seems to have endless power (love it )... But i'm worried about the long term. I also have STi hood scoop for a little better air cooling (assume this has very little effect though)...

Is my baby gonna be ok? just tured 32k miles the other day... My fiancee seems to think that she is now my 2nd love... (dangerously too close to call... )
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post #2 of 5 Old 04-11-2003, 12:44 AM
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I would be willing to bet you are. I was running lean with just CAI (Injectors running at 100% and still lean)... I would install some sort of inj viewer (UTEC, or Piggy back, etc) to find out.
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post #3 of 5 Old 04-12-2003, 01:16 PM Thread Starter
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THank you...

How do you know you were running lean...???

I've read other discussions on this site that suggest they had CAI and stock computer and the effect on air/fuel ratio was absolutely minimal... and they had air/fuel gauges to back it up.

Is you CAI running lean estimate based on a gauge reading also?
and if so, to what degree are you running lean.... enough to damage the engine, or minimal effect?

Thanks again.
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post #4 of 5 Old 04-14-2003, 09:15 AM
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I wouldn't be able to guess... However with the catless exhaust I would be willing to bet just a little lean. Unplug your negitive battery cable over night then plug it in and drive your car hard for 30 miles. Continue to drive hard for 2 days. That should make your ECU equal up the AFR. However, if all these mods have been done, I would get a UTEC or some ECU tuning device.
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post #5 of 5 Old 04-15-2003, 11:12 PM Thread Starter
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Thanks... will do...

l
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