Low boost and horsepower?

Discussion in 'SRT Hellcat Performance' started by Mopar22, Feb 9, 2016.

  1. Mopar22

    Mopar22 Silver Member

    Joined:
    Jan 9, 2016
    Messages:
    185
    Likes Received:
    83
    Trophy Points:
    198
    Location:
    New Mexico
    Vehicle:
    Challenger SRT Hellcat
    Is there an issue with my hellcat? Last week I did a few WOT runs and on my performance page max boost was 9psi and max hp was 637 , it was 47 deg outside. Today I did a few more WOT runs and boost maxed out at 9 psi and hp only got up to 589, outside temp was 63 deg. I have 963 miles on the car and live up at 5,300 ft above sea level. Are the low numbers a result of the altitude or possibly something else? On another thread others report seeing as high as 720 hp. Anyone with knowledge on this subject? Thanks.
     
  2. Hammer Down

    Hammer Down Gold Member

    Joined:
    Jan 11, 2016
    Messages:
    400
    Likes Received:
    253
    Trophy Points:
    233
    Location:
    South Jersey
    Vehicle:
    Challenger SRT Hellcat
    That would be the best answer. Many have seen like 2lbs less boost in high altitude.
     
  3. Top Cat

    Top Cat Gold Member Hellcat Car Club Gold Supporting Member Fastest Cat/Record Holder HCC Charter Member

    Joined:
    Nov 26, 2014
    Messages:
    1,925
    Likes Received:
    1,079
    Trophy Points:
    768
    Location:
    Doylestown,Pa
    Vehicle:
    Challenger SRT Hellcat
    In that elevation you could get away with a Metco 2.85 upper pulley and NO tune.
    TC
     
    • Like Like x 1
    • Agree Agree x 1
  4. NorCaletch19He77Kat

    NorCaletch19He77Kat Silver Member

    Joined:
    Aug 30, 2015
    Messages:
    905
    Likes Received:
    270
    Trophy Points:
    173
    Vehicle:
    Challenger SRT Hellcat
    you know this horsepower screen can be deceiving--unless you wind it up just right, in just the right gear at the right grade and elevation--you may never actually see 707--I live at sea level and have seen a lot of 650-690 readings and I don't think it means anything really. at your elevation, you are probably handicapped to the numbers you are seeing--unless there is another specific performance issue like engine/cylinder miss, hesitation or check engine lights, you are probably just fine..

    just drive the shit out of it and have fun--I'm sorry, drive the HE77 out of it..
     
    • Agree Agree x 1
  5. Fast cat

    Fast cat BANNED Hellcat Car Club

    Joined:
    Sep 23, 2014
    Messages:
    2,267
    Likes Received:
    713
    Trophy Points:
    498
    Location:
    Indiana
    Vehicle:
    Challenger SRT Hellcat
    Top cat how much boost did you lose after doing the headers and exhaust? I was thinking that Ross (craven) told me that they seen a loss of about 2 lbs.
    Witch made me think if a person would do the full exhaust with ported heads if they could get a way with a 2.85 with out a tune. What are your thoughts?
     
    • Like Like x 1
  6. Top Cat

    Top Cat Gold Member Hellcat Car Club Gold Supporting Member Fastest Cat/Record Holder HCC Charter Member

    Joined:
    Nov 26, 2014
    Messages:
    1,925
    Likes Received:
    1,079
    Trophy Points:
    768
    Location:
    Doylestown,Pa
    Vehicle:
    Challenger SRT Hellcat
    Last outing I had the same pulley set up as Linda and she made one lb more boost, I find it interesting that the cars that changed to ported and polished heads and a cam have no gains over stock, I don't think the heads are the issue but more in the cam that was used.
    TC
     
    • Useful Useful x 1
  7. Fast cat

    Fast cat BANNED Hellcat Car Club

    Joined:
    Sep 23, 2014
    Messages:
    2,267
    Likes Received:
    713
    Trophy Points:
    498
    Location:
    Indiana
    Vehicle:
    Challenger SRT Hellcat
    Who ran faster?
     
  8. Mopar22

    Mopar22 Silver Member

    Joined:
    Jan 9, 2016
    Messages:
    185
    Likes Received:
    83
    Trophy Points:
    198
    Location:
    New Mexico
    Vehicle:
    Challenger SRT Hellcat
    I was thinking about that and was going to call HHP to ask.
     
  9. Tweaked

    Tweaked Hellcat Member

    Joined:
    Mar 28, 2015
    Messages:
    93
    Likes Received:
    30
    Trophy Points:
    18
    Vehicle:
    Charger SRT Hellcat
    I live at 3700 elevation and yes you can swap pulleys and car will be fine without tune. However with a tune it will be faster. Been there done that.
     
  10. Ray Hunsaker

    Ray Hunsaker Silver Member Hellcat Car Club Gold Supporting Member HCC Charter Member

    Joined:
    Jan 26, 2015
    Messages:
    511
    Likes Received:
    140
    Trophy Points:
    153
    Vehicle:
    Challenger SRT Hellcat
    im at 4500 ft I got 9 lbs boost, changed to metco 285 pulley no tune took it out yesterday I was getting between 12 and 13 lbs boost witch im thinking a little higher than I expected. it might be the ass cold weather here will see?
     
  11. Top Cat

    Top Cat Gold Member Hellcat Car Club Gold Supporting Member Fastest Cat/Record Holder HCC Charter Member

    Joined:
    Nov 26, 2014
    Messages:
    1,925
    Likes Received:
    1,079
    Trophy Points:
    768
    Location:
    Doylestown,Pa
    Vehicle:
    Challenger SRT Hellcat
    It was Linda's day,she set the Charger number 9.71 and if she hadn't gotten the boot as I did would have taken my number,;)
    TC
     
  12. Mills

    Mills Silver Member

    Joined:
    Jan 28, 2015
    Messages:
    584
    Likes Received:
    133
    Trophy Points:
    153
    Location:
    Airdrie, Alberta
    Vehicle:
    Challenger SRT Hellcat
    Question: what results in more booster - ATI Lower or Metco 2.85" upper?

    Or should state perhaps: which one increases the speed of the supercharger more by pure math...not what someone has seen on their dash gauge ;)
     
  13. Mopar22

    Mopar22 Silver Member

    Joined:
    Jan 9, 2016
    Messages:
    185
    Likes Received:
    83
    Trophy Points:
    198
    Location:
    New Mexico
    Vehicle:
    Challenger SRT Hellcat
    What's the difficulty level to swap to the 2.85 pulley?
     
  14. Mills

    Mills Silver Member

    Joined:
    Jan 28, 2015
    Messages:
    584
    Likes Received:
    133
    Trophy Points:
    153
    Location:
    Airdrie, Alberta
    Vehicle:
    Challenger SRT Hellcat
    Hit the Metco threads in the vendor section and there are some good reads and pics of guys who have done it. Fairly straight forward...not for the faint of heart
     
  15. Rick@Metco

    Rick@Metco Gold Member Hellcat Supporting Vendor

    Joined:
    Sep 7, 2014
    Messages:
    308
    Likes Received:
    165
    Trophy Points:
    293
    We manufacture the supercharger pulley rings in six sizes, from stock (3.35") all the way down to 2.40".
    The 2.85" pulley is generally worth 3-3.5 lbs of additional boost.
     

Share This Page

Search tags for this page

hellcat boost