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Thread: 2 Step Launch and Transmission input question.

  1. #1

    Default 2 Step Launch and Transmission input question.

    I've purchased your EFI LS system and in the instructions it lists that in order to activate the optional 2-step, it needs to be connected to a 12V source. So... am I understanding it correctly that I simply need to run this blue wire to say... the battery... make sure it's set up in the system through the controller (to make sure it's "turned it on" and set an RPM), and any time I'm at a stop and mash the throttle, the 2-stage RPM limit will activate at my pre-set RPM until I launch. I do NOT need to hook this up to a switch to activate or anything like that, and don't need a way to deactivate the 12V source for any reason.



    Am I correct in my thinking here?



    Second... I'm having trouble understanding the Calibration speed and everything setup. I've got a T-56 from an 01 Camaro with all it's stock sensors still in place (though un-used at this point). Can I use one of my stock sensors and connect this somehow... or what do I need to do to provide the EFI Ls with this reference signal so I can get the "smooth transitions between shifts or for quick transitions from high rpm to idle conditions"? Also... will I use one of the wires to connect to a tachometer so I can see what RPM's I'm running at?

    EDIT: I wanted to add the details of my setup...

    • 1993 Nissan 240sx
    • Ls2 from an 05 Corvette with Cadillac CTS-V accessories (no AC)
    • Trans Am/Camaro T-56

  2. #2
    msdtech1955 Guest

    Default 2 Step Launch and Transmission input question.



    I've purchased your EFI LS system and in the instructions it lists that in order to activate the optional 2-step, it needs to be connected to a 12V source. So... am I understanding it correctly that I simply need to run this blue wire to say... the battery... make sure it's set up in the system through the controller (to make sure it's "turned it on" and set an RPM), and any time I'm at a stop and mash the throttle, the 2-stage RPM limit will activate at my pre-set RPM until I launch. I do NOT need to hook this up to a switch to activate or anything like that, and don't need a way to deactivate the 12V source for any reason.









    you would need to hook it to a :



    1) push button --for momentary 12 volts)



    2) clutch switch



    3) transbrake solenoid.





    msdforms@msdperformance.com







    Latitude: 31.730125
    Longitude: -106.29673









    Attached files


  3. #3
    msdtech1955 Guest

    Default 2 Step Launch and Transmission input question.

    Second... I'm having trouble understanding the Calibration speed and everything setup. I've got a T-56 from an 01 Camaro with all it's stock sensors still in place (though un-used at this point). Can I use one of my stock sensors and connect this somehow... or what do I need to do to provide the EFI Ls with this reference signal so I can get the "smooth transitions between shifts or for quick transitions from high rpm to idle conditions"? Also... will I use one of the wires to connect to a tachometer so I can see what RPM's I'm running at?



    EDIT: I wanted to add the details of my setup...



    on the manual transmission connection for smoother shifts : unfortunately not,

    and yes there is a tach outout wire...





    msdforms@msdperformance.com







    Latitude: 31.730125
    Longitude: -106.29673








  4. #4

    Default 2 Step Launch and Transmission input question.

    You missed one of my questions...

    "Can I use one of my stock sensors and connect this somehow... or what do I need to do to provide the EFI Ls with this reference signal so I can get the "smooth transitions between shifts or for quick transitions from high rpm to idle conditions"?"

    Thanks.

  5. #5
    msdtech1955 Guest

    Default 2 Step Launch and Transmission input question.

    no sir, not even the gm ls crate motor kits and hot rod lane have that feature.

    msdforms@msdperformance.com







    Latitude: 31.730125
    Longitude: -106.29673








  6. #6

    Default 2 Step Launch and Transmission input question.

    I don't understand what crate motors have to do with my question...



    My question is... if I can't use a factory GM sensor to give the Atomic EFI LS system an input for "smooth transitions between shifts or for quick transitions from high rpm to idle conditions"... what can I use? What thing must I buy to supply this signal? A sensor, some kind of system... what? If your system needs an input, what do I need to have to give it what it wants?

  7. #7
    msdtech1955 Guest

    Default 2 Step Launch and Transmission input question.

    My question is... if I can't use a factory GM sensor to give the Atomic EFI LS system an input for "smooth transitions between shifts or for quick transitions from high rpm to idle conditions"... what can I use? What thing must I buy to supply this signal? A sensor, some kind of system... what? If your system needs an input, what do I need to have to give it what it wants?





    no sir, it will not do it ....



    nor, will it take any inputs from a standard transmission .









    msdforms@msdperformance.com







    Latitude: 31.730125
    Longitude: -106.29673








  8. #8

    Default 2 Step Launch and Transmission input question.

    MSDTech1955 wrote:

    My question is... if I can't use a factory GM sensor to give the Atomic EFI LS system an input for "smooth transitions between shifts or for quick transitions from high rpm to idle conditions"...

    what can I use?

    What thing must I buy to supply this signal?
    A sensor, some kind of system... what?
    If your system needs an input, what do I need to have to give it what it wants?





    no sir, it will not do it ....



    nor, will it take any inputs from a standard transmission .







    Man... you guys are KILLING me! Do you even read past the first few words? I'm starting to regret purchasing this thing if you all can't take the time to read my question in total so you can give me the answer I need. Let me break it down even smaller for you.



    What do I have to hook up to give the MSD EFI LS a speed signal?



    Now... got it? Okay... let's hope we can continue...



    Your manual says...



    "Calibrate Speed: If there is speed output on the transmission,
    a reference signal can be delivered to the Atomic LS.

    This will assist in smooth transitions between shifts or

    for quick transitions from high rpm to idle conditions.

    The Power Module has a Brown wire and a Light Blue

    wire. These wires connect to a magnetic pickup on a

    driveshaft such as a driveshaft sensor from Racepak.

    To program the calibration, have a passenger use the

    Handheld Monitor as you drive to 40mph. Once 40

    mph are obtained, select YES on the handheld. This will

    calibrate the speed input."

    So... what is it looking for?

  9. #9

    Default 2 Step Launch and Transmission input question.

    Ok, hopefully I can help out a little bit.



    The two-step does only have to have a 12v input, but it does have to be switched. If you hook it up to a permanent 12v, it will always be on. It should be hooked up to a clutch switch, or other momentary switch as MSDTech1955 pointed out.



    The speed sensor is a two wire input on the tailshaft of your transmission. You can get a pigtail from the dealership. We didn't include one because there are couple different ones and the length varies a bit from car to car. The polarity does not matter on the wires, so you should be able to hook them up to either one on the pigtail. It will be our brown and lt. blue wires on the pigtail.

    Once it is hooked up, calibrating it is as easy as pushing the calibration button when you get to the 40mph mark (you can use a GPS app or something similar -- I recommend having a passenger do this so you can keep your eyes on the road). It will allow the IAC to see the vehicle moving and will help the transition back to idle on quick clutch stabs by increasing the commanded idle while you are moving (very similar to the OEM stuff).



    The tach output wire is a 12v square wave and works on almost all aftermarket tachs using the gray wire from our harness.





    One very important thing to note: You will need the latest updates to make use of the two step -- they will be on the website in the next two days (probably tomorrow actually). There are quite a few improvements in it including a much better throttle response and improved idle stability (along with the added two step feature). Please note that the two step is really for racing only and can damage any emissions equipment you have installed (it is an ignition cut for fast off the line response, not a fuel cut).



    If you have any more questions, please let us know.



    Thanks,

    Michael Wittkopf

    EFI Engineer @ MSD Performance


  10. #10

    Default 2 Step Launch and Transmission input question.

    Mike... you are the man. Thank you. This was exactly what I needed to hear. One last question, since we're on the subject.





    What happens at high RPM (racing application) shifting if the 2-step is connected to the clutch switch? Won't it initiate fuel-cut, making for something like Heal-Toe downshifting (where you're on the brakes, clutch in, and blipping/rev-matching on the throttle with your heal before releasing the clutch) impossible? Or does it work in a different way?





    The car I'm putting this in is a drift car/autocross vehicle... so I may be somewhat unique (at this time) on my expectations and needs out of this system. I'm looking forward to seeing how it performs on a race track! I'll make sure to update the firmware before I fire it up.

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