High Altitude help

Discussion in 'SRT Hellcat Performance' started by Chippy, Apr 25, 2015.

  1. Chippy

    Chippy Silver Member

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    Some of us unfortunately do not live at or even close to sea level. I personally have air here at about 5000ft. We generally lose about 2 pounds of boost. My guestion is would a pulley change to get some or all of that lost 2 pounds back set off codes or put into limp mode? Thank you in advance. And if not which pulley and maybe who could make them. One last thing is the belt a dodge specific or can you get something aftermarket in different sizes?
     
  2. Titletaker

    Titletaker Hellcat Member

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    The east coast guys have it made.
     
  3. KLR CAT

    KLR CAT Active Hellcat Member

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    Pulley will help for sure, but will need tuning. More airflow means MAF transfer will need to be tuned, as well as Power enrichment tables.
     
  4. Chippy

    Chippy Silver Member

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    So even if we're losing approx 2 lbs boost still needing tune if just trying to get boost back up to stock levels? Which if can be done I'm OK with but what a pita.
     
  5. B5 Blue

    B5 Blue Platinum Member

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    ;););););)
     
  6. Cruisin1966

    Cruisin1966 Silver Member

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    Do you even have your car yet? ;)

    You know I'm just poking the bear, lol
     
  7. KLR CAT

    KLR CAT Active Hellcat Member

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    Tuning is not about boost, its about airflow and the calibration of the MAF to determine that airflow. Flow and Density are different things. You are down on boost and HP relative to sealevel due to less dense air, and less oxygen content in it. Spinning the blower faster increases airflow consumption before the rotors and across the MAF, and increased charge density post rotors into the heads. The ECU determines fueling based on that airflow. a Certain MAF frequency is an expected to be a certain airmass, and a commanded injector pulse to fuel towards that airmass appropriately. Now the hellcat looks to use both MAF and MAP, and I haven't seen the stock calibration myself yet, so I'm not exactly sure what strategies the ECU uses, but generally anything that changes airflow into and out of the motor substantially ( and a 20% overdrive is substantial) needs to be calibrated correctly.
     
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  8. Chippy

    Chippy Silver Member

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    Thank you for the explanation.
     
  9. VanishingPoint

    VanishingPoint Silver Member

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    The good news is, everyone is on the same playing field at that elevation, so no fear.

    IIRC, NA cars lose 3%, and blown cars 2% per thousand feet?
     

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