"optimal" A/f ratio for supercharged 4.6

Discussion in 'SN95 4.6L Mustang Tech' started by 98stangv8, Dec 18, 2008.


  1. 98stangv8

    98stangv8 New Member

    Joined:
    Oct 4, 2003
    Messages:
    1,037
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fayetteville, nc
    Hey guys,

    I have a 98 block with a v2SQ...what is the optimal a/f ratio I should be shooting for when my car gets dyno tuned tomorrow morning?

    Thanks!
    #1
  2. squeak93

    squeak93 Active Member

    Joined:
    Jun 2, 2005
    Messages:
    1,142
    Likes Received:
    5
    Trophy Points:
    49
    Location:
    Joplin, Missouri
    14.7 is ur static a/f...

    12.5-13 depending on how safe want to go.

    Lean is fast, fat is safe.....
    #2
  3. 2002BLGT

    2002BLGT Well-Known Member

    Joined:
    Dec 18, 2003
    Messages:
    2,949
    Likes Received:
    3
    Trophy Points:
    59
    Location:
    Bedford VA
    for wide open throttle with stock engine 11.8-11.5 and with built engine 11.7-12.0
    #3
  4. squeak93

    squeak93 Active Member

    Joined:
    Jun 2, 2005
    Messages:
    1,142
    Likes Received:
    5
    Trophy Points:
    49
    Location:
    Joplin, Missouri
    I tuned my 351 n/a fox to 11.5-12... was telling him a bit safer #'s for the blowers sake...
    #4
  5. CobraRed_96_GT

    CobraRed_96_GT Active Member

    Joined:
    May 20, 2006
    Messages:
    1,651
    Showcase:
    2
    Albums:
    1
    Likes Received:
    1
    Trophy Points:
    39
    Location:
    UCSD/La Jolla
    :nonono:12.5-12.6 is where my car is safe - 13 would be too lean even for me
    #5
  6. 2002BLGT

    2002BLGT Well-Known Member

    Joined:
    Dec 18, 2003
    Messages:
    2,949
    Likes Received:
    3
    Trophy Points:
    59
    Location:
    Bedford VA

    anything higher than 12 is not considered safe with a blower
    #6
  7. PAzYearazzUP

    PAzYearazzUP Banned

    Joined:
    Dec 12, 2008
    Messages:
    41
    Likes Received:
    0
    Trophy Points:
    0
    Bingo! :nice: 11.9 Pea Yes Eye dare little blow machine is 10 is overkill is you shoot for the 11'somwhere is BLGT is not blowing lean up yer waste gate.
    #7
  8. CobraRed_96_GT

    CobraRed_96_GT Active Member

    Joined:
    May 20, 2006
    Messages:
    1,651
    Showcase:
    2
    Albums:
    1
    Likes Received:
    1
    Trophy Points:
    39
    Location:
    UCSD/La Jolla
    I don't have a blower. High compression with heads/cams. I'm saying his blower a/f recommendation is closer to my N/A range - and even still too lean:shrug:
    #8
  9. the98stang

    the98stang Active Member

    Joined:
    Aug 12, 2005
    Messages:
    2,412
    Likes Received:
    0
    Trophy Points:
    47
    Location:
    Clovis, CA
    On a forged motor and boost you can safely tune for 12 flat. On a stock engine I would say no more than 11.8 AFR . Be sure the timing is 16 or below if you are running pump gas...
    #9
  10. 98stangv8

    98stangv8 New Member

    Joined:
    Oct 4, 2003
    Messages:
    1,037
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    fayetteville, nc
    Cool...around 12 then...I am at 13 now without the blower, just the engine...does that mean I am running lean or rich? Lower the number, the higher or lower the fuel content?
    #10
  11. CobraRed_96_GT

    CobraRed_96_GT Active Member

    Joined:
    May 20, 2006
    Messages:
    1,651
    Showcase:
    2
    Albums:
    1
    Likes Received:
    1
    Trophy Points:
    39
    Location:
    UCSD/La Jolla
    Low means rich. 13 is fine stock n/a. Most shoot for 12.9-13.1
    #11
  12. blubullett

    blubullett Member

    Joined:
    Jun 23, 2006
    Messages:
    541
    Likes Received:
    4
    Trophy Points:
    18
    Location:
    Modesto, CA
    Mine is 11.6 to 11.8 and I passed emissions with flying colors (in california too) and my car runs great.
    #12
  13. squeak93

    squeak93 Active Member

    Joined:
    Jun 2, 2005
    Messages:
    1,142
    Likes Received:
    5
    Trophy Points:
    49
    Location:
    Joplin, Missouri
    Ignore me.... Posting at work causes dislexia(sp)....



    11.5 for a blower..12.0 on a n/a. My counting was backwards for some reason... my bad. :D
    #13
  14. 2002BLGT

    2002BLGT Well-Known Member

    Joined:
    Dec 18, 2003
    Messages:
    2,949
    Likes Received:
    3
    Trophy Points:
    59
    Location:
    Bedford VA
    whos tuning it ? hopefully not Haywood ?
    #14
  15. CobraRed_96_GT

    CobraRed_96_GT Active Member

    Joined:
    May 20, 2006
    Messages:
    1,651
    Showcase:
    2
    Albums:
    1
    Likes Received:
    1
    Trophy Points:
    39
    Location:
    UCSD/La Jolla
    12.0 is too rich for a N/A 4.6:thinking:
    #15
  16. billfisher

    billfisher Active Member

    Joined:
    Jul 17, 2005
    Messages:
    1,294
    Likes Received:
    2
    Trophy Points:
    38
    Location:
    huntsville, AL
    you know, my opinion is"it depends". i noted the factory WOT a/f for the gt500 (11.8).

    for my setup, it has the same c/r as the gt500(8.5:1) but i think i am going to risk a bit leaner. but my combustion chambers will have no sharps. and my temps will be cooler than a stock car(160).
    #16
  17. BK_CAULEY

    BK_CAULEY it's built for speed not longevity, woman

    Joined:
    Dec 26, 2006
    Messages:
    1,764
    Likes Received:
    0
    Trophy Points:
    37
    Location:
    Thomasville, ga
    what the **** are you babbling about?
    #17

Share This Page