7531 help

On our Digital 7 7531 we have power to the step 1 retard wire all the time for ease of setting the timing. If we use the gear retard curves...will we have to unhook our step 1 retard wire so it doesn't think we are taking off in 2nd?

Josh

 

Mike is the guy for these ignitions, and is correct, as usual. Some additional info to consider.

Yes, the step retards are separate from the gear retards and the launch and run curves, etc... The thing you have to remember is they add together. If step one is active, then it is active all the time, and any other retards you set up will 'stack' on top of it. So, no, you don't have to eliminate it, you just factor it in.

-Brian

 

Am I reading this wrong? This is straight off MSD's site on the 7531's instructions:

Gear Select
The Three Step Retard wires, Pink (1), Violet (2) and Tan (3) can also be wired to indicate the first three gear changes to the ignition control. When selected from the Step Wire menu, the ignition will know that the car is in second gear when 12 volts are applied to the Pink wire, third for the Violet and fourth when the Tan wire is applied to 12 volts. By using this feature, if you lift off the throttle and get back on it, the ignition will not count it as a gear change.

 

What it is saying is you have two ways to put in a gear retard.

1. Set the programmable gear retards to whatever retard you want in each gear, then let the box sense that you have shifted from one gear to the next by watching for a pre-configured rpm drop during each gear. The problem is if you pedal the car, and the rpm drops below the pre-configured shift threshold, then it loads the retard for the next gear, even if you didn't shift.

2. Hard wire the step retards to the shifter mechanism, so that in one gear it energizes step 1, next gear step two and so on. That way, the first step stays energized until you physically shift gears, even if you pedal. When you shift, step 1 de-energizes, and step 2 energizes, and so on.

If you are using step 1 as a quick way to set your base timing, option number 2 won't work very well because you only have two step retards left to work with (unless you run a powerglide).

Right now I use step 1 as a quick way to set base, and the launch curve for first gear and the run curve for second, and let the box sense the rpm drop to switch curves. I use the curves instead of a straight gear retard because for now I want to adjust timing by rpm during each of the two gears (powerglide).

-Brian

 

Okay thanks Brian, that's what we're wanting to do....leave the step 1 retard active, as well as use the gear retard curves.

Josh