Air to Fuel Ratio - CAI before and after - Page 2
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This is a discussion on Air to Fuel Ratio - CAI before and after within the Engine Modifications forums, part of the Tech & Modifying & General Repairs category; Originally Posted by Heide264 Post up some logs, including long term/short term fuel trims from the ECU then. I'd be ...

  1. #16
    MAINEiac 11blackSTi's Avatar
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    Quote Originally Posted by Heide264 View Post
    Post up some logs, including long term/short term fuel trims from the ECU then. I'd be curious to see the fuel trims through the power band. I'd be surprised if it actually matched up across most of the MAFV range. I had a lot of issues in between 2-3V when adding my intake.

    The irony of the situation (if I am not off my rocker): If the car didn't use fuel trims to compensate for a fueling error, and the MAF housing is the same diameter, then you didn't gain anything by going with the intake. Same MAFV, same voltage, same fuel, same burn ratio.... Same air flow. This applies to everything - WOT response, low load cruising, and while in transient.
    At work right now, so I can't post anything currently. My air/work ratio is not looking very good currently

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    Registered User EndlessSea's Avatar
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    so many intake haters on this forum. i find the hate comical actually.

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    Quote Originally Posted by EndlessSea View Post
    so many intake haters on this forum. i find the hate comical actually.
    I think you're confusing "hatred" with knowledge. Specifically the knowledge that slapping an intake on a car and not scaling the MAFv on a Subaru is rarely EVER a step in the right direction. Do you have anything else to add?
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    Registered User Heide264's Avatar
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    Quote Originally Posted by EndlessSea View Post
    so many intake haters on this forum. i find the hate comical actually.
    I personally have a cold air intake. I don't hate them by any means.

    On the other hand, I do hate general ignorance (even though I am admittedly guilty of it occasionally and incidentally, as we all are). Assuming that throwing an intake on will be "okay" is, at this point, general ignorance. I can go into detail as to why it's dangerous with the newer ECUs, but I doubt anybody would listen anyhow (outside of those that already know).

    Rescaling the MAF is simple and should be done, in my opinion, even when it was not your intake that changed. VE changes in these cars are done using the MAF scaling (in some way/shape/form). It's easy. Your fuel trims can cover up an issue for a little while, and maybe 99% of the time, but that isn't all inclusive.

    It's like wearing protection... 99% of the time you will probably be okay... That 1% will cost you though.
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    Quote Originally Posted by EndlessSea View Post
    so many intake haters on this forum. i find the hate comical actually.


    haters = people who use tools such as math and science to make informed decisions

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    Quote Originally Posted by Heide264 View Post
    Rescaling the MAF is simple and should be done, in my opinion, even when it was not your intake that changed. VE changes in these cars are done using the MAF scaling (in some way/shape/form). It's easy. Your fuel trims can cover up an issue for a little while, and maybe 99% of the time
    While not ideal by any means, it's a start: HOWTO: One Man's Way of Scaling a MAF - NASIOC

    Quote Originally Posted by Heide264 View Post
    It's like wearing protection... 99% of the time you will probably be okay... That 1% will cost you though.
    wow. You just compared an STi to, well, an STI!

    EndlessSea, I've owned 4 intakes over the years. I don't consider myself at all a "hater," unless it refers to the definition proposed by MainFrame.
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    Quote Originally Posted by 11blackSTi View Post

    I think my next upgrade might be a manual or elecontrol boost control to see if I can get the AFR leaned out a little (high 11's maybe?) to get a little more power, as 11 seems a bit rich.

    Any thoughts?
    This would be a step in the wrong direction,considering a boost controller is used to control boost,not AFR's. Low 11 AFR is fine on a Subaru.
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  9. #23
    Registered User Heide264's Avatar
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    Quote Originally Posted by Donkey View Post
    This would be a step in the wrong direction,considering a boost controller is used to control boost,not AFR's. Low 11 AFR is fine on a Subaru.
    Do you mean to infer that pushing the car to a (conceptually) higher load doesn't make the car run leaner? Blasphemy. Everybody runs leaner AFRs at higher loads =P
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    Quote Originally Posted by Heide264 View Post
    Do you mean to infer that pushing the car to a (conceptually) higher load doesn't make the car run leaner? Blasphemy. Everybody runs leaner AFRs at higher loads =P
    If that was sarcasm, you forgot the orange. I seriously doubt that an intake would put the car into untuned load cells. Yes, the EBCS may (and probably will), but depends on how aggressive you tune your WGDC.
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  11. #25
    Registered User Heide264's Avatar
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    Quote Originally Posted by zax View Post
    If that was sarcasm, you forgot the orange. I seriously doubt that an intake would put the car into untuned load cells. Yes, the EBCS may (and probably will), but depends on how aggressive you tune your WGDC.
    It was sarcasm. Was geared towards the idea of using higher boost levels to raise your AFR. Nothing to do with using "untuned" load cells, just the fact that going to higher load isn't gonna raise your AFR.. just move you over in the table a bit to around the same AFR.
    Quote Originally Posted by Trainrex
    He was throwing balloons filled with sulfuric acid and shrapnel at the swat team. They finally had to take him down with rubber bullets.
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  12. #26
    He simply abides. SD_GR's Avatar
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    OK so, again thinking out loud... what should the OP do at this point? My gut feeling is (a) nothing and (b) post logs.
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  13. #27
    Registered User Heide264's Avatar
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    Quote Originally Posted by SD_GR View Post
    OK so, again thinking out loud... what should the OP do at this point? My gut feeling is (a) nothing and (b) post logs.
    Post logs (or better yet, graphs).

    1.) WOT pull with target fuel and wideband o2 across the power band. Include A/F Learning as well.
    2.) Include a plot of AF correction + AF learning over MAF(V) for a longer drive (maybe 30 minutes if possible)
    Quote Originally Posted by Trainrex
    He was throwing balloons filled with sulfuric acid and shrapnel at the swat team. They finally had to take him down with rubber bullets.
    2011 STi Build Log
    -Part 1 - Reading, Data Logging, and Analyzing Data
    -Part 2 - Turbocharger 101 & Basic Boost Control
    -Part 3 - EcuFlash, Experimental Defintions, and a Drive By Wire Intro

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