MSD 8973 tech question

Trying to find some use in this box....

Will the rpm related functions of the box, shift light, timers, etc., still work even if the box isn't hooked to the mag?

In other words, can I hook it to the coil so that it picks up RPM, so that it can operate the shift light, launch light, timer function, etc., but not hook it to the mag so that I don't have to worry about anything jacking with the timing?

Or does this thing not work when hooked to the mag?

 

Will, one of these days you will probably understand that your phobia of the MSD 8973 was only based on that incorrectly shielded crank trigger cable and not on voodo in the box. You should not condem the MSD 8973 for lifetime of ridicule with so many people having such success with it. I do believe that some racers had a few bad experience with it either because they didn't understand the operating instructions and set the parameters incorrectly, or it wasn't wired up correctly or the use of an unshielded crank trigger cable. You are going to find out that in certain classes that you will be left behind if you don't learn to use some of the features in the box. On cars like ProMods the Two Step launch, the launch retard, and numerous other features really help cars with suspensions and blower motors. The software in the 8973 is tried an proven software that has been around since the start of the MSD Digital 7 in the 1990's and the basic core software is used in all the other MSD computerized ignitions and ignition accessories. Just look at all the ProStock and Top Fuel guys using the same basic software without problems. Software can't just do something that it is not programmed to do. Software does not have a mind of its own. If it did then you should worry everytime you get in your car and drive on the road or everytime a commercial plane flies over your house or anything else that uses software. Maybe you have watched fictious movies live "I Robot" or the "Terminator" too many times(lol). Go ahead and give it another go in your new ride and you will fall in love with it.

 

Doug I believe that showed up on the Digital 7 when racers started using 16 volt batteries. It was not a software problem.

 

Thanks Doug, but that is still a hardware problem. I haven't heard of that problem before but I will file it away for future reference.

WJ you are 100% correct that chip plug in the top of the Points Box is only for the RPM limiters and like you said not for timing.

 

Doug, it would be hard to say without seeing the setup. How do you know it wasn't retarding on the hit? Also when you check the timing after you start the car do you first apply 12 volts to the blue wire that goes to the 8973 to reset it into the run "get set and run mode". Without that 12 v reset the 8973 stays in the Run Retard Curve and not the Launch Retard Curve.

 

8973

Apparently this box works much better when nestled behind a steel firewall. I don't know. I know I've seen it do some pretty stupid stuff on two TAFC's I worked on and have heard countless other stories from other TAFC/TAD teams I know.

I'm a business major and a business owner, not an engineer. That makes me a bottom line kind of guy. I don't get hung up in the why. If someone that I know didn't hurt parts before they put that box on their car, started hurting stuff, took the box off, quit hurting parts, I don't need to know what exactly the box is doing.

That said, I've yet to hear one of these stories from a Pro Mod racer. Thus it seems this box works in door cars. It also may have something to do with the vibration/shake in the alky cars being solid suspension. Some of the Top Dragster guys who said it works in their car may not shake near as much as a TAD/TAFC does.

As far as being left behind I don't know of any TAFC's in the top ten running that box. Any of the useful features of that box can be achieved through analog devices such as the six shooter, two steps, rpm switches, etc. Not to mention I don't like dragging a laptop and a cable to the staging lanes to make changes. Not to mention there are other knobs to turn on the tuneup other than timing retards.

As Tom Conway said, these cars aren't that smart...

If someone wants to run this box, have at it. If they want my opinion and experience with the box in TAFC, that's my position. I'm considering running this box in the Pro Mod I'll be driving for the Dallas race, but will have it out of the car by next year. Call me old school, but I plan on swapping feet and shifting it myself. A six shooter and Leahy box is just fine with me.

 

I cannot see what shake has to do with the 8973. It can't shake the ones and zero in the software. The six shooter, the points box and the Racepak all survive in that environment. I agree that a TAFC doesn't need or use all the features the box offers either because of their situation or the rules but you will find out the ProMods do because of the rear suspension and the heavier weight. The launch retard is the only way you can really get off the line with a ProMod and the Two Step makes the launch very consistent with no foot swapping. I don't really know of a reason why you need to take a laptop in the staging lanes for a 8973 and I know of none that do. I would highly recommend that you give the 8973 a fair chance in the ProMod you are going to drive. I think you will learn to appreciate it. If you need help with the 8973 feel free to call me or email me.

 

Rodney, their has to be something causing that.
1. Do you have any retards set in the programs anywhere including start retard?
2. Where do you have the blue reset wire attached to? Is it wired to the clutch switch?
3. When you have a laptop hooked up to the 8973 and the motor running have you watched the "Monitors" section in the upper left window. It will tell you if any retards are going on or off.
4. Have you watched the "gauges" in the lower left window to see if the retard needle pointer move?
5. What speed does you motor idle at?