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  • boostedsl2
    replied
    Originally posted by tt_tony
    would the spark being blown out sound like detonation?
    i'm thinking thats exactly whats happening.

    i thought the same a long time ago. you won't feel detonation unless its a big bang and your motor is usually toast my the time you feel it. detonation feels like hesitation. it sounds like someone is dropping a bunch of beebees down the exhuast. these arn't very loud usually. you can usually barly hear it over a motor at full throttle.

    if you can hear detonation, you've probably already screwed somthing up.

    if your bucking during acceleration, its probably too rich and/or your plugs are gapped too much. gap them down until it quits missing. if that doesn't do it, keep them gapped down and lean out the mix to see what happens. do this under light throttle and slowly push into full throttle and make sure to watch the gauge.

    your engine should be able to take a little lean mix for a couple seconds if its only in the high 12's or low 13's.

    make sure to check your plugs. if your unsure what they are supposed to look like, post them up and we'll help you figure out whats going on. if your going to do this, remeber to mark which cylinder they came out of.

    Leave a comment:


  • S.Bretz
    replied
    No. I use those plugs with over 20psi no w/ no problems.

    Try strapiing the IAT to the upper raditor hose to pull some timeing.

    What the boost at? Compression?

    Ian was running 20+psi with 92 cali crap gas, but he didn't have stock cams (helps alot to prevent detonation) and a compression between 8.5 and 9.

    Leave a comment:


  • tt_tony
    replied
    would the spark being blown out sound like detonation?

    Leave a comment:


  • tebriel
    replied
    i would try gapping them down to .030. are you sure it's detno and not the spark being blown out/drowned out from having too much gas? at 10:1 you're going to be washing down your rings hardcore and drowning the spark.
    -teb

    Leave a comment:


  • tt_tony
    replied
    yeah, it looks like the stock system at WOT is like 10:1 then the boost comes in and it starts creepin up. WOT at higher rpms it's still low 12's but im still getting some detonation/pre-ignition.

    i can only get 91 octane here in phx, i dont think thats the problem though.
    im running the ngk bkr7e-11's at .035" should i try a different plug?

    Leave a comment:


  • tebriel
    replied
    exactly, but the systems we are using probably aren't the most exact, and the people tuning aren't trained. :-D That's why I always add that margin of safety in there. run a little rich, lose a little power, but keep on driving towards tomorrow [img]{SMILIES_PATH}/wink.gif[/img]

    my problem has always been running too rich though, washed down the rings a bunch of times and that's why i'm rebuilding that engine now.
    -teb

    Leave a comment:


  • S.Bretz
    replied
    If you have precise control over all cylinders, then you want 13.1:1. At that ratio, the flame travels the fastest. So you add timing advance until you see no power gain, then back off a little. If you get a richer or leaner, the flame will travel slower, so the advance can't cause spark knock, BUT a leaner, hotter mixture can heat up a part of the chamber and cause it to detonate ro deisel.

    If you can get 13.1and then then get timing tuned, you can add a splash of fuel back in to make a safety margin....adout 12.5-12.8 (depends on how well balanced your injector/air flow is)

    Leave a comment:


  • tebriel
    replied
    i agree with mike, i've actually gone a little leaner over the years under boost, going from 11.8 to 12.1:1 full throttle high boost.
    low boost part throttle i go for 12.5. 12.5 is the leanest i go under boost.
    -teb

    Leave a comment:


  • boostedsl2
    replied
    you want it as high as you can get it under cruising without hesitation or bucking. this is usually 15~16, but some engines can sustain higher a/f's without problems.

    under boost you want to be below 12.0:1 anything higher and your getting a little too lean. some tuners take it out to 12.5:1 on pump, but thats a little lean for my liking. 10's is too rich. you want to be in the 11's

    part throttle boost and low boost values can be in the 13's. if you richen this area up too much, you'll get terrible gas milage. you dip in and out of this area quite a bit under low throttle driving and the higher a/fs won't hurt anything.

    the big thing is to check your plugs. should be a black base and a while strap. electrode should look clean, meaning there shouldn't be black, white or brown residue on it or the porcelen. if you can get it to look like that under part throttle and full throttle, your the man.

    Leave a comment:


  • MorePonyPWRthanU
    replied
    yep 15-16 is ok n/a....you will probably see 10's under WOT because of the rich ass stock tune.

    Leave a comment:


  • S.Bretz
    replied
    Yeah...15-16 under cruise is normal...you may see and occasional 16-17 afr.

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  • jts749
    replied
    Originally posted by tt_tony
    cruising? cuz it's reading like 15.3:1 most of the time. im wondering if i have some exhaust leak that's causing that
    cruise=no boost, right?
    therefore 15.3:1=ok ,right?

    Leave a comment:


  • Syn
    replied
    Originally posted by liamrh
    Originally posted by tt_tony
    what type of readings should i be getting with the stock fuel system while cruising? cuz it's reading like 15.3:1 most of the time.
    Scary.
    x2 [img]{SMILIES_PATH}/shock.gif[/img]

    Leave a comment:


  • liamrh
    replied
    Originally posted by tt_tony
    what type of readings should i be getting with the stock fuel system while cruising? cuz it's reading like 15.3:1 most of the time.
    Scary.

    Leave a comment:


  • tt_tony
    replied
    cool, didnt kknow that about the heater.

    what type of readings should i be getting with the stock fuel system while cruising? cuz it's reading like 15.3:1 most of the time. im wondering if i have some exhaust leak that's causing that

    Leave a comment:

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