VEC timing advance with a 10lb pulley

Discussion in 'Gen II' started by ViperBing, Mar 25, 2009.

  1. ViperBing

    ViperBing Enthusiast

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    I anyone running any timing advance over stock with a 10 lb pulley on 93 octane?

    How about with race fuel?

    thanks in advance!
     
  2. EllowViper

    EllowViper Viper Owner

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    Pretty ball-z if you are getting away with zero timing adjustments with 10 lbs of boost...but GREAT question that I'd like to find out about too! When I gernaded my #3 on a 6.5 lb with W/M I was running zero retard (stock timing) once the W/M kicked in...and I guess I got enough detonation to kill a ring land on my #3 piston. With my 10 lb forged motor up with a better W/M set-up, I'm still retarding about 6-7 degrees give or take throughout the RPM band. I haven't really tuned it too tightly yet however since I just installed a progressive W/M card from Sean. So to answer your question, I'm still running '"retarded" on 93 octane with a 10 lb setup.
     
  3. Russ M

    Russ M Enthusiast

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    With 10 psi you should not be running more than 15 degrees total timing under boost, if you are then you should start investing in a new motor. Or driving around on 118 octane fuel or pure meth.
     
  4. EllowViper

    EllowViper Viper Owner

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    "Theoretically" timing this beast at WOT isn't too tough of an equation based on the open loop timing curve Sean provides with his VEC instructions. I have not verified this timing curve via logging an ODB-II data stream however. Working off memory here, I recall max WOT timing is "something" like this:
    2000 RPM=25 BTDC
    3000 RPM=24 BTDC
    4000 RPM=22 BTDC
    4500 RPM=22 BTDC
    5000 RPM= 28 BTDC
    5500 RPM=29 BTDC
    6000 RPM= 30-31 ?? BTDC
    So what is the right approach for retarding the timing?? Depends. Rule of Thumb 1 degree per PSI? This engine loves timing. Like I said, before I "blew" the piston, I was running a very aggresive timing curve and the engine just loved it...but I was mistaken in my plug choice (stock plug). So was it the timing or plug that created my situation. The stock extended reach plug theoretically adds 2 degrees of timing based on the location of the source of ignition..plus the additional electroid heat contributes to pre-ignition. Now that I'm running the NGK two step colder plugs, that factors into the overal timing advance equation as well. Eitherway, retarding the timing at 10 PSI is a must. How much and when is the question to be answered.
     
  5. BOTTLEFED

    BOTTLEFED Viper Owner

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    good info Eric

    I"m guessing that both contributed to your piston failure
    too much advanced timing on the cast pistons creates excessive heat and stress on the weak ring lands and causes them to break

    I refer to the example settings on this website to get an idea on timing settings
    they go from mild to wild ;)
    SOME TIPS AND INFORMATION ABOUT VIPER TUNING
     
  6. EllowViper

    EllowViper Viper Owner

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    Tim,
    Great link...Thanks!! Hadn't seen that before. Gives me some further ideas to mess around with. I pushed the timing up a bit Sunday and messed with my Progressive W/M a bit too and the motor really responded. My W/B is overheating so I have to stop messing around when that goes belly-up. I guess I need a new sensor and the $79 heat sink. My aluminum heat sink isn't enough. Man, I get 12 psi "RIGHT NOW" WHEN
     
  7. EllowViper

    EllowViper Viper Owner

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    ...I mash the peddle. A redesigned manifold w/integrated intercooler would sure be nice. I keep designing that in my head...
     
  8. BOTTLEFED

    BOTTLEFED Viper Owner

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    the direct-injection water/meth system you made seems like you already accomplished that ;)

    sounds like you are having fun with your new setup :D

    too bad we just got 4 new inches of snow so I can't go out and fine tune my setup
     
  9. EllowViper

    EllowViper Viper Owner

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    I hear you man...I'm in Colorado Springs this week...28 degrees, chance of snow...grey dreary skies. Makes me appreciate the sunny and 80 degree Tampa weather I left behind...much like San Diego this time of year! Year 'round driving in Florida is priceless. Just need to fix my A/C now!! Always something...plus my drivers window is starting to function very slowly now...doesn't even go down on "cold"days without cycling the switch a few times.
     

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