Help, complete drop in LOAD during WOT - Page 2

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  1. #16
    Member Array raetza's Avatar
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    Maybe the S/C pulley is slipping on the shaft? I checked and the center bolt is very tight....I'll take it off...

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  3. #17
    Member Array raetza's Avatar
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    Ok, S/C pulley off...inconclusive. Have you EVER seen a KB pulley slip on the shaft? The bolt was VERY tight as I said...but there is nothing positive to keep it from slipping (spline, key, etc). Maybe I should coat the friction surfaces with red loctite?

  4. #18

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    Quote Originally Posted by raetza View Post
    Anyone have any fresh ideas for me on this? I was convinced that I had S/C belt slip...but have now discounted this as a possibility. I am fresh out of ideas on what to look for! :(

    Again, for review...I have logged the following:
    1) LOAD and MAP (both inferred) drop suddenly while WOT with a sudden loss of power. Let off of the throttle and get back on it and it goes again for a bit until the same event re-occurs.
    2) SPARK remains constant through the event until LOAD drops, then it increases
    3) No indications that I have logged show the throttle coming off of WOT until I release it (after the power loss)
    4) Injector Pulse Clockticks remain constant until the power loss, at which time they drop
    5) A/F (set currently at 7.4 for high load on E85) go richer than my Wideband will measure (< 6.7) at the time of the power loss
    6) My Boost gauge drops from 15PSI to under 0 instantaneously at the time of the power loss
    7) Airflow through the MAF decreases almost in half at the time of the power loss
    8) Belt is not slipping
    9) Tires are not slipping
    10) KB Bypass is not opening (I tested by tying it shut)
    11) If I remain WOT after the power loss, the car struggles along as you would expect it would with A/F being hugely rich. Boost will NOT return until I let off the throttle for about a second and then stab it again.

    Thanks to anyone with ideas!
    Is your wideband measuring lambda and converting to a/f? What is the stoich set at? What is the commanded lambda at wot?

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  6. #19
    Member Array raetza's Avatar
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    Yes...and A/F is programmed to 9.7 on my gauge(Stoich in my tune). WOT lamda is.74
    Last edited by raetza; 04-13-2012 at 08:58 PM.

  7. #20
    Member Array raetza's Avatar
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    Eric, what's your opinion on pulleys on KB? Kenne Bell is so dramatic about their products ...to the point of being emotional. They state, "... The drives on all Kenne Bell superchargers utilize a unique friction drive design. The pulley shoulder mates against the seal ring and creates a steel-to-steel frictional "bond". There is no keyway or other method of "holding" the pulley against the seal ring to prevent slippage....". I have read how they "hate" any aluminum non-slip rings like I am using (BilletFlow). I used BilletFlow BECAUSE they have a steel hub that maintains the "steel to steel frictional bond". But...KB also states that "Slotted pulleys (non-slip) will take out the drive and gears in the supercharger...because we need some slip in the belt on the pulley..."! This is from KB techs.

    Anyway, I am CERTAIN that my belt is not slipping. I am NOT certain that the hub isn't slipping some...but I am doubtful that it is slipping enough to completely unload the boost...I would see massive gouging, heat discoloration, etc if that were the case. I've probably recreated this boost loss event over 50 times...and that would have done some damage if it were a frictional problem.

    Thanks for your input...just want your opinion on the pulley rings -vs- KB opinion.

  8. #21
    Premium Member Array Eric Brooks's Avatar
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    I have never had an issue with non KB pulleys

  9. #22
    Member Array raetza's Avatar
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    PROBLEM SOLVED! Thanks Eric, it would have taken me a lot longer to figure out without your suggestion...it was the intake collapsing! I have a 4" 90 degree silicone connector between the intake tube that turns down into the front bumper to the MAF and air filter. The tube was collapsing at high air volumes. I made a support "spring" that I put inside the tube out of a SS TIG welding rod...and no more loss of air! Back to the tuning process

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