MSD Grid

Discussion in 'PSI Superchargers Tech Questions' started by Matt, Jan 12, 2022.

  1. Matt

    Matt Member

    Joined:
    Jun 25, 2006
    Messages:
    105
    Likes Received:
    0
    I’ve been having some issues with my grid, on 3 occasions after releasing the button timing has failed to drop and output switch hasn’t activated. Last run failed to engage the 2 step on the button, racepak shows launch and release, no timing drop, smoked tires on release caught motor on upper limiter. I have run grid in real time without motor running at least 50 times does what is programmed perfectly. I will replace the grid, I’m wondering if anyone else has had anything similar, I’ve been using grids for 10 years with out any issues.
     
    #1
  2. HootersFunnyCar

    Joined:
    Nov 27, 2003
    Messages:
    251
    Likes Received:
    8
    did you look at the Re-view on grid? What did it show?
     
    #2
  3. Matt

    Matt Member

    Joined:
    Jun 25, 2006
    Messages:
    105
    Likes Received:
    0
    No I haven’t, will do that, never really used review always relied on racepak.
     
    #3
  4. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,594
    Likes Received:
    177
    Have you hooked up the blue grid wire so it only gets 12 volts on it when the trans brake button is depressed?
     
    #4
  5. Matt

    Matt Member

    Joined:
    Jun 25, 2006
    Messages:
    105
    Likes Received:
    0
    I use a button on the steering wheel and have a roller switch on the throttle pedal only gets power to the blue wire when pedal is past 50%. I didn’t have a card in the grid either.
     
    #5
  6. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,594
    Likes Received:
    177
    I would suggest the blue wire power is your problem. If it has continuous power to the blue wire then the Grid does not run. When power is applied to the blue wire it resets everything and gets it ready to run and when power is taken away from the blue wire then it starts and runs. This is why it should only get its power from the trans brake button. So when the TB is depressed it sends power to the Grid via the blue wire and it is ready set and waiting. Now when the TB is released on launch it also takes power away from the Grid so it starts at the launch. Also when power is applied to the blue wire it puts the Grid into the Two Step mode and releases the Two Step rev limiter when power is taken off the blue wire. Another reason it needs to be hooked up to the Trans Brake button for a converter car or a clutch switch for a clutch car.
     
    #6
    Last edited: Jan 15, 2022
    Will Hanna likes this.
  7. Matt

    Matt Member

    Joined:
    Jun 25, 2006
    Messages:
    105
    Likes Received:
    0
    I’ve been using the grid since they have been available, with clutch and converter, the data shows power to the blue wire,
    “MSD Launch”, 2 step should have been active, it wasn’t, data shows release of button, timing didn’t drop as it should have, the rev limiter caught the motor. When testing on laptop it works faultlessly, I’m figuring grid has an intermittent issue that maybe vibration is causing, I’m going to put a new grid on car and see how it goes, was wondering if anyone else has had similar issue.
     
    #7
  8. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,594
    Likes Received:
    177
    So what is the purpose of the roll switch that applies power to the blue wire past 50% throttle?
     
    #8
    Last edited: Jan 16, 2022
  9. Matt

    Matt Member

    Joined:
    Jun 25, 2006
    Messages:
    105
    Likes Received:
    0
    Power from the trans brake when activated goes to the roller switch, when the throttle is depressed actually way less than 50% probably 10% it sends power to the blue wire. All this does is stop timing coming out until the transbrake button is activated and the throttle is depressed.
     
    #9
  10. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,594
    Likes Received:
    177
    Matt, if I read you correctly both your problems of 1. No Two-Step on stage and 2. No timing curve activation on launch are both indicative of no 12 volts being applied to the Grid when the Transbrake Button is depressed. My guess would be that roller switch circuit being intermittent. My recommendation is to remove it and use the Grid features to control the timing when the TB is pressed and staging.

    If I understand you correctly you do not want to apply timing retard when the TB is pressed and that can be done by a setting in the Grid. If you go to the Grid Instructions on Page 8 under the LAUNCH RETARD paragraph it states "When launch retard is active, the retard value is the placement of the first dot". So if you put that first dot on the timing curve at zero degrees and zero time then when 12 volts is applied by the TB the timing retard curve will NOT be active until the TB is released. Then place the second dot at .02 seconds (you can use .01 sec but I like .02 for insurance) out at the retard value you want for launch.
     
    #10
    Last edited: Jan 17, 2022
  11. Matt

    Matt Member

    Joined:
    Jun 25, 2006
    Messages:
    105
    Likes Received:
    0
    Hi Mike correct me if I’m wrong, on racepak data it shows on
    MSD launch the step up when I apply transbrake and it drops back when I release the button, I assume that the information that the racepak sees has to come from the grid through the v net cable.
    The reason for the roller switch on the throttle pedal is to stop timing drop on release of the button when moving into 1st gear and reverse after the burnout, we are sometimes pulling 17 degrees for longer than 1 second to control the tire on launch.
     
    #11
  12. Mike Canter

    Mike Canter Top Dragster
    Staff Member

    Joined:
    Mar 10, 2004
    Messages:
    4,594
    Likes Received:
    177
    Most Promods do that with two Trans Brake buttons. One that goes direct to the Trans Brake without power to the Grid using a diode to isolate it and a normal Trans Brake button to the brake and the Grid for launch.
     
    #12

Share This Page