Cold Air Intake Issue?

Discussion in 'Fiesta ST Chat and Discussion' started by joe@2j-racing, Dec 5, 2013.

  1. joe@2j-racing

    joe@2j-racing Active Member

    Tuning a Nissan Juke, UpRev found that a kink in the Injen cold air intake cause boost inconsistency by creating turbulence around the MAF and gave incorrect readings to the ECU. The ECU calcs boost based on MAF Voltage.

    The odd part is, this wasnt apparent until a free flowing downpipe was installed. When they reinstalled the OEM intake the boost inconsistency went away.

    Just something to think about once we all start adding more parts to the 1.6L
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  3. COBB

    COBB Active Member

    MAF based tuning logic (directly measures incoming air) cars are very sensitive to air intake changes which is why a tune is required when you modify the intake. However, many modern cars like the BMWs we support or the Focus ST and Fiesta ST use speed density (calculates incoming air via other sensor input) tuning logic. Therefore, you can make modifications to the car without effecting the tune. However, it is torque based tuning logic, so modifications without tuning won't make a very big impact on power since the car will by trying to meet the same torque targets even with free flowing parts installed. We have done some dyno testing and tuning with a wide variety of parts installed and haven't seen any issues. And before you ask, I unfortunately don't have dyno plots to share just yet ;)

  4. RodMoe

    RodMoe Well-Known Member

    show me the sheets and ill show you the Benjamin's LOL o_O;)
    LotusZX3 and COBB like this.
  5. stuntdoogie

    stuntdoogie Active Member

    Pics or it didnt

    Sent from my SPH-D710 using Tapatalk
  6. McRib 1s Back

    McRib 1s Back Well-Known Member

    This has since been nicely answered/addressed, but I wondered this too. I had a first year Juke with the same Injen intake -- and there is plenty of chatter on those boards about that. I'm relieved that we don't appear to have the same issue (though I always thought speed density systems were lower tech/accuracy alternatives). Most of my JDM experience is tuning Nissan cars (SR20DE/T stuff, 300ZXTT, 350Z, 370Z), so I've pretty much always been a MAF guy. Oh yeah, that 370Z made incredible gains with open source tuning, lots of dyno runs, and a "race pipe". It also sounded great until about 6.5K, then you just heard the very harsh noise of rough combustion, ending the party. :)

    As an aside, I abandoned the Juke pretty fast and never got good tuning results. With lightweight wheels, intake, and exhaust it was marginally faster than my friend's MK IV GTi in roll-on contests.
    late apex likes this.

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