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Thread: A/f Ratio?

  1. #1
    Join Date
    Jan 2008
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    Question A/f Ratio?

    OK IM FINALLY GETTING MY WIDEBAND GAUGE!! SP WHAT ARE THE GOOD NUMBERS AND THE SCARY NUMBERS?? ITS ON MY 08' 4.8 112 RADIX.

    RITE NOW IM AT STOCK 5-6PSI,IM GOING TO DO THE PULLEY SWAP FOR 7-8LBS.

    AND YES IM ADDICTED TO BOOST

  2. #2
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    Boost guys could tell you more but I'd say 12:1 or leaner would scare me.....but I'm not very brave.

  3. #3
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    Quote Originally Posted by GasGuzzler View Post
    Boost guys could tell you more but I'd say 12:1 or leaner would scare me.....but I'm not very brave.
    you should be in the 10/11 range in full boost. 14-15 cruising.. thats what mines at
    1951 3100
    1984 C10

  4. #4
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    Mid to low 11's while in boost and 14-15 while cruising as Ducky said. Anything in the high 11's low 12's while in boost is getting on the edge. Make sure you watch your KR as well.

    2004 Silverado Crew Cab, forged iron 5.7, STS w/MP turbo, 10+ psi, FMIC, Tial 50mm BOV, Vic Jr, Snow performance meth, MTI Stealth cam .220/.220 .581/.581 115lsa, Comp chromoly pushrods, Yank TT3000 stall, LS1 Efans, 160 tstat, Trucool 40k trans cooler, 60# injectors, Walbro fuel pump, Patriot springs, Built 4l65E w/billet input & output shafts, Eaton posi, SD tuned...all installed by Klein North Automotive

  5. #5
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    x < 11.5 under boost and 14.5-15.5 cruising.
    12 Sec. Club! SOLD
    La Viuda negra/ a.k.a. Black Betty

    LQ4 6.0L, WCCH HEADS, LEVEL 5 FLT 4L80E TRANS. WITH TRANS BREAK, YANK 3200 STALL, TRICK TURBO, TURBONETICS T-76 TURBO, CUSTOM INTERCOOLED, 68lb INJECTORS, CUSTOM S/D TUNE FROM NELSON PERFORMANCE, COMP CAM 212/214 .557/.559 116+2, SNOW METH. KIT, . ALL INSTALLED AND DYNOED AT NELSON PERFORMANCE: 5**?HP @ 5073rpms and 5**TQ @ 4389rpms AT THE WHEELS WITH 10 PSI OF BOOST. ALL 3/4 TON TRUCK 5435LBS, NOTHING TAKEN OFF, STREET TIRES, AND USUALLY 2 BABY SEATS. WANNA RIDE?
    SOLD***

  6. #6
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    im with the 10.8-11.5 guys at WOT
    2006 silverado SS....Clifford Jr...turbo coming soon
    1970 Chevelle ly6 swap....d1 coming soon

  7. #7
    Join Date
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    Quote Originally Posted by mean05 View Post
    im with the 10.8-11.5 guys at WOT
    +1

    I dont like seeing my N/A setup over 12.8-9

  8. #8
    Join Date
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    Good rule of thumb for a safe tune:

    10.8-11.2 for forced induction
    12.5-12.7 for N/A

    More aggressive numbers:
    11.5-11.7 for FI
    12.8-13.2 for N/A

    Someone posted some screenshots from the ZR-1 tune over on the EFILive forum, and it commands as rich as 10.4:1 when in boost. I believe the stock PE tables in our truck tunes command 10.8 or 10.9:1 on our N/A motors.


    2006 GTO M6 Brazen Orange
    2006 Silverado CCSB Duramax


  9. #9
    Join Date
    May 2004
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    2,120
    Here's the instruction to the A/F meter I use. At the bottom there's a chart for reference.

    http://www.fuelairspark.com/Instructions/170450.pdf


    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

  10. #10
    Join Date
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    Sounds like you got your answer, if it's richer than 11.2, that's ok until you get up here,
    see you soon,
    allen

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