NHRA Legal MSD Timing Control

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by nitrohawk, Dec 2, 2006.

  1. nitrohawk

    nitrohawk New Member

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    What is the part number of the MSD timing control that NHRA has made legal to run in the TAD class?
    Can this timer also be used to control electronic fuel valves for the hi speed?
     
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  2. Crew

    Crew Volunteer

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    The NHRA posting didn't list a part number. It did say that it is allowed for the timing unit to control pneumatically operated valves. To me, this means that the fuel valve must be air operated but can be controlled by an electric over air switch. It would be much easier to use an electric solenoid on the fuel valve itself, but the rule doesn't seem to read this way.
    .
    Did any one else read the rule revision differently?
     
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  3. Mike Canter

    Mike Canter Top Dragster

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    I agree that the rule change was not really thought out or NHRA has some other agenda that I couldn't figure out. On our ProMod we use the MSD 8973 Pro Mag Digital Controller that has one time or RPM switch (only one) that controls a electrical solenoid for the high speed lean out. It is direct with no other air interface and makes it real easy. Changng the main jet does not change the pressure at the high speed lean out poppet. I use use Digi-sets to electrically control other solenoids for fuel control. Why NHRA still wants to complicate things with electric over air has me totally confused.
     
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  4. Crew

    Crew Volunteer

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    Mike, What are you using to start the timer for the system? We used to have an air switch under the pedal.
     
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  5. nitrohawk

    nitrohawk New Member

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    electric over air

    So as the new rule(as of now) reads you still have to use the air operated valves? This means I guess that all you can change is the timer itself and the MSD box only allows one adjustable time channel for the fuel managment.
    How many ign. timing changes can you preset?
    Do you still need the retard box?
    Do you need 12 volts for the new MSD timing control?
    Will the 12 volts when removed by a switch kill the engine?
     
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  6. Crew

    Crew Volunteer

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    MSD said the six shooter is not required.

    An external 12 volt source is required. I assume it will kill the engine. MSD makes a capacitor to give you a few seconds of power if your lose the source.

    You will still need the whitey valve but no other air pcs. You will need an electric solenoid to control the air to the whitey.
     
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  7. Mike Canter

    Mike Canter Top Dragster

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    We use a clutch switch and a WOT in series to start our secondary Digi-Sets. The primary RPM switch/time switch in the 8973 is initiated by the clutch switch. The 8973 has to have a 12 volt reset wire (medium blue wire) that both resets and initiates the box. The 12 volt signal is applied to the box when the clutch is in and this resets the box into a "get ready to go mode". The reason this is required is it has to know that you are starting in first gear so it can reset all the retards, the timer, and the adjustable shift lights for each gear. Without that reset wire the box is lost in the ether. So take this as a warning. The same reset function is used on the Digital 7. I have had guys call me up and ready to pull there hair out because they didn't read instructions.

    Here also is some good data that took me a while to learn. If you have looked at the MSD software for a 8973 or a 7531 on your comuter you will see several timing curve graphs on the right side of the screen. The one at the top is called the "Launch Retard Curve" but that is really the 1st gear curve and is only used when you are in first gear. Once you shift it changes to the "Run Retard Curve" for 2nd and 3rd gear. (If you haen't looked at the software this is going to be confusing). If you fired up the motor without the clutch in (which you never do) both the 8973 and the 7531 start in the "Run Retard Curve" and stays there until you push the clutch in and give the MSD a 12 volt signal then it switches to the "Launch Retard Curve". So as long as you have he MSD wired correctly this is transparent to you but you can see what happens if you don't hook it up right.

    Now you totally understand that then let me continue to scramble your brains. The way I set the timing is at 30* at idle and then I have the MSD box pull out 4* so I am at 26* actually. I put 4* retard into both my Launch Retard Curve and my Run Retard Curve and in my brain I let that be 26*. The first time I start it I use the timing light and adjust it so it is right at 26* with the 4* in the MSD box. So from then on if I check the timing with a light and it reads 27* then change my Curve by another degree to correct it to 26*. I never have to move the mag with the motor running and get zapped and let it go again. Now using my baseline that got me to 26* I, ontop of that, advance and retard the ignition based on RPM. Where it gets complicated is if you launch at 29* and want to pull out 3* at 7500 RPM and then stay at 26* (all made up figures) for the rest of the run then you have to start the Launch Retard Curve at 1000 RPM at -1* retard on the graph (really 29*) and then at 7500 go to -4* on the graph(really 26*) in the rest of the Launch Retard Curve and all of the Run Retard Curve.

    If you never want to change your timing through the entire run then you can have zero degrees in the Launch Retard Curve and the Run Retard Curve and set the timing exactly where you want it at 26* and adjust the mag just like you have been doing it.

    Also remember that all the retard functions add together when each one is activated.
     
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  8. Mike Canter

    Mike Canter Top Dragster

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    And no you do not need the retard box or a six shooter anymore. Sorry forgot.
     
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  9. nitrohawk

    nitrohawk New Member

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    Thanks for the information. Sounds a little complicated. I am running an a-fuel
    dragster I guess I would be using time not rpm to control the timing. Probably could use rpm by referencing my computer graft but probably not the best way for this application. I like to start the motor at about 7 degrees less and do the burnout then switch over to the launch timing before staging. I accomplish this now by applying 12 volts to the # 1 chip channel on the six shooter when the on/off switch is turned on. After the burnout I turn on the air supply which is connected dirctly to # 2 chip channel, then use air timers to control the timing on the other four channels. Will the MSD timing control allow this?
    Thanks again for your responce as I have no experience with the MSD box and before buying would lie to have some information.
     
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  10. Mike Canter

    Mike Canter Top Dragster

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    Yes you can use one of the three switched auxiliary retards. You can wire in a switch to either of them to be turned on just during burnout. You also have a burnout RPM limiter than can be used in conjunction with it. That leaves you two auxiliary retards that can be activated via a 12 volt switched source such as air/electric switches or timers. I think you are going to have to switch to a timing curve to try and get the same thing as you are doing now.
     
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  11. T.Howell

    T.Howell Member

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    I believe the software can be downloaded from MSD's Pro Mag site.
    Then you can play around with it to see how easy it really is.

    I think NHRA will will "recomend" a certain boost number to kill or retard the ignition in the event of over boost from a push rod, lifter, rocker, failure.

    Of course after a year or two of "recomended" it will become "required".
     
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  12. Mike Canter

    Mike Canter Top Dragster

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    Since we have yet to have a failure that has resulted in an overboost I was wondering how much the boost will go up with one cylinder out. 2 lbs, 4 lbs or what? You need the Racepac boost sensor to make that function work.
     
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  13. lowcountry71

    lowcountry71 New Member

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    mike - i run an original msd 7530. how do you get around the default time for retarding timing? i know your post talks about a 7530T but i believe both have the same time default. i don't want to retard my motor by rpms - i want to retard it via time. is the only answer to make a timing curve and download it or is there an easy way to use the programer to bypass the limited default time for retarding the motor? also have you every changed the firing order in the 7530 to use plug #6 for the inductive pickup? my distance from plug #1 to the digital unit is over their recommended distance of the fiber optic cable. i've heard that one can reset the 7530 firing order and use any plug for the pick up cylinder - plug #6 is closer for me and it meets the fiber optic cable length.
     
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  14. Dave Germain

    Dave Germain New Member

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    Mike, Mathematically speaking you wouldn't expect boost to go up more than a couple of pounds. Unfortunately I have had valve train failures and we spiked over eight pounds higher. The spike doesn't last long as it leans out the next couple of holes in the firing order and the rods exited soon afterwards. Dave Germain
     
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  15. Mike Canter

    Mike Canter Top Dragster

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    As far as I know the 7530 does not have a time retard function such as what we are talking about in the 7531 or the 8973 so I don't know what default time for retarding timing you are talking about is. Explain it more to me.

    Since a 7530 does not have built in selectable firing orders like the newer boxes it doesn't make any difference which you designate the first cylinder to fire in a sequence. What you have to make is a cheat sheet to carry with you that will tell you what the order is if you start at #6 being #1 and continuing on. The only time the Digital 7 uses that sync fiber optic line is right at start up for a few revolutions then it doesn't use it anymore until you shut the box off.
     
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  16. lowcountry71

    lowcountry71 New Member

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    the 7530 has the ability to retard based upon time from 1st function (tranny brake, line loc - blue wire from msd). the retards are programable and add up just like you say a 7530T does. normally one programs the retard via rpm drops such as shift points when the motor drops say 800 rpm. no problem there but what if you want to retard before a rpm drop and not after? they have a limited time value (less than .25 secs) that you can time delay the retard. what good is .25 secs if you want to retard before the 1/2 shift at 2 secs? i'm wanting to retard the motor via my racepak rpm curve on a time basis. if i have to i will make a timing retard curve and download but before i went this way i wanted to know if there is any easy way to bypass the .25 sec default time. i have not been into a 7530T - i thought it was the same as a 7530 but with out the ability to have "traction control". the msd programing disks for a 7530 + 7530T are basically the same - both appear to allow one to make a timing (retard) graph (even individual cylinders) triggered via possibly by the inductive pickup.
     
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  17. Mike Canter

    Mike Canter Top Dragster

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    Just so we are talking the same. i believe that function is called the Launch Retard that can be set from 0.0 time to a max 2.5 seconds in .01 second intervals. Is that correct. I know of no other timed retard.
     
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  18. nitrohawk

    nitrohawk New Member

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    Down load

    I tried down loading the software from MSD site but it came up site not available. I did however find the sheet on the MSD 8973 that I picked up from MSD at Dallas.
    Are you using the indidule cyl. option? Why would you change an indivudle cyl? Maybe to control detonation ???
    Bob Holley
     
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  19. Mike Canter

    Mike Canter Top Dragster

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    The individual cylinder timing option is used to make up for crankshaft twist or other problems in uneven timing. On a nitrous motor and a blown alcohol motor I read the position of the "Blue Line" on the spark plug ground electrode to show me where the timing is in each cylinder. If 5 or more read in the same position I will adjust the other 3 individually to make them all agree. I do not know if a nitro motor makes a "Blue Line" on a ground strap.

    Try this link for the software download
    http://www.msdignition.com/1softdownload.htm
     
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  20. lowcountry71

    lowcountry71 New Member

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    mike - you are correct. if you print out the instructions from the disk it says .25 secs but the controller defaults to 2.5. if you go into the shift modes you will find the rpm drop retard features. when the 7530 1st came out the pro stockers were using it for traction control by time. they found a way to bypass the 2.5 sec default and hide their TC without using the ignition curve mapping. i am trying to find out how to get past the 2.5 default time without making a curve by time in the xy graph feature.
     
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