Welcome to CPGNation.com! Log in or Sign up to interact with the CPGNation community.

XIM coil on plug Dwell settings for AEM smart coils

Discussion in 'FAST Support Forum' started by Blownnova72, Jan 7, 2019.

  1. Blownnova72

    Blownnova72 New Member

    Joined:
    Jun 3, 2016
    Hey guys,
    I was wondering if anyone had some suggestions for the Base dwell settings table for the AEM smart coils. As well as the dwell modifier vs TPS table.
    I'm using the fast xfi as well as the XIM module. It's a procharged SBC that will be running around 28lbs of boost on c16. The motor last time around made just over 1500hp. The car does alot of 1/4mile racing but is also driven on the street, so I wanted to make sure the lower TPS areas weren't too high of a dwell that could over heat the coils.
     
  2. Turbobitt

    Turbobitt Member

    Joined:
    Nov 14, 2010
    Typically run about 5-5.5 ms dwell at 100 TPS and reduce it down with the dwell modifier table to about 45% at 0 TPS and ramp it to 100% at about 75% TPS. Basically run max dwell near or at full throttle and reduce it down some at low throttle angles/low cylinder pressure.

    I've played with reducing the dwell further at low TPS but I found that I was getting some fouled plugs and misfires when I street drove the car.

    Above all, make sure you are below 18 Volts at all times. Coils are rated to 17 max but that is with safety margin with 18 volts being the unofficial absolute highest. Above 18 volts, the coils will discharge extra voltage to ground and ultimately burn out the coils.

    AG.
     
    Last edited: Jan 7, 2019
  3. Blownnova72

    Blownnova72 New Member

    Joined:
    Jun 3, 2016
    Thanks for the reply, I will try that. I had in my head to try about 5ms at 100% TPS and ramp it down to around 3ms at idle. So what you said is pretty much that. I run a 14 volt system in the car so it hitting 18 volts should never be an issue.
     
  4. Fastmanefi

    Fastmanefi Well-Known Member

    Joined:
    Jun 4, 2011
    Location:
    Sonora, CA
    5ms under high rpm/load and 2.5ms idle with a ramp in between works very well.
     
  5. Blownnova72

    Blownnova72 New Member

    Joined:
    Jun 3, 2016
    Do I set the dwell vs voltage as my base dwell or the max dwell? Then is the modifier a percentage of that or a percentage gain from that number?
    I had thought it was my max dwell then the modifier was a percentage of that at a given TPS. So lets say I set the dwell to 5ms on the dwell vs voltage table. At 100% on the modifier table would it be 5ms? And then let's say 50% would be 2.5ms?

    I'm only asking because when you read the Fast instructions on that it makes it seem like you enter your base dwell then the modifier is the percentage gain from that. Then I read another thread on here and it was opposite of the fast instructions.
     

    Attached Files:

  6. Turbobitt

    Turbobitt Member

    Joined:
    Nov 14, 2010
    Set the dwell vs. voltage table as the max dwell and the modifier table will reduce it by whatever level you ramp it down to.
    AG.
     
  7. Blownnova72

    Blownnova72 New Member

    Joined:
    Jun 3, 2016
    Thanks Turbobitt.
     

Share This Page