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1fastmustang
05-11-2006, 07:03 PM
I have a 7531 and I'm trying take timing out of the engine at the time of launch which is achieved with launch retard and down track after the shift. I've been told that each curve is cumulative. What's the best way to take some timing out at the launch, return the timing and then pull timing out again at a specified RPM or time down the track for first gear and then again for second and third? Is that possible?

Thanks in advance for any help.

msdtech4
05-24-2006, 12:47 PM
1fastmustang,

There is a section in the data tree under retards. It is labeled launch which will allow you retard up to 15 degrees for up to 2.5 seconds. The gear retards are gear specific and will retard that amount in that gear. These will all work in conjunction with one another.

Thanks,

MSD tech4

1fastmustang
05-25-2006, 10:39 AM
I understand the launch retard. But down track I still need some clarification. Here's a hypothetical: Let's say I retard timing by 2 degrees at launch for 2/10s of a second. Then, I want to pull out 2 degrees in 1st gear lets say between 6000 and 7000 RPM's will that 2 degrees be put back in at the gear change? Will there actually be four degrees out? What if I pull more out in just prior to shifting to third? I've been told that the timing curves are cumulative, and that each curve builds on the previous, so I think I am pulling more timing than I want out of my motor. Thanks in advance for your help.:)

Eric David Bru
05-25-2006, 12:28 PM
I was thinking they were cumulative, but upon re-reading the manual, I am not sure either...

GEAR RETARDS
This program provides the ability to create a run curve for each gear. Up to six different curves can be programmed from 800 12,500 rpm in 0.1 increments for every 100 rpm. You can program up to 32 different points on each Gear Map. Also, all of these points are interpolated every millisecond to create a smooth (no steps) curve. The number of gears is adjustable under the SHIFT menu, as well as the amount of rpm drop the ignition needs to see before knowing that a different gear has been selected. Up to six gears can be programmed. You can also use the Step Retard wires as Gear Select Indicators for the first four gears. These retards are mapped out on the Gear Retard chart of the Graph View. In the chart, go to the View pull down menu and select Trace Box. That will give you a small window to show the different color gear traces so creating a different curve for each gear is easier. If you want the same retard curve for all gears, compose the curve, select the Edit pull down menu and copy the curve, then select Paste All.

It appears to me that the retards reset at each gear change.

Eric David Bru
05-25-2006, 12:48 PM
The reason for the confusion is because of page 5 of the manual:

PROGRAMMABLE FEATURES
The following explains the programmable features of the PN 7531 Ignition. The features are listed in the same order that they show on the Data Editor list in the software. Note that all of the retard amounts are cumulative and the maximum amount of retard is 30. The gear curves are independent.

msdtech18
05-26-2006, 11:10 AM
OK the 7531 has 6 gear graphs that you could custom tailored for each gear, because the box recognizes each gear change the plot for each gear are NOT accumulative. For example if you wanted to run a two degree retard in each gear you would plot 2 degrees in each gear. Now if you didn't want those two degrees in second gear but you do in the rest. Then you would leave the second gear at o.

1fastmustang
06-01-2006, 07:30 PM
Thanks for all the great information!! I have a few more questions. Is the down track timming retard achieved by setting up the gear retard curve? Is trace one 1st gear, trace two 2nd gear and so on? After you set up the curves is there anyother changes that need to be made in the Data Editor file to complete the timing curve?

Thanks

Eric David Bru
06-02-2006, 11:52 AM
The down track timing is set in different ways, launch retard, step retard or gear retards.

The gear traces are separate colors as shown in the menu box. After you get your retards set you need to make sure they are saved/uploaded to the Digital 7.

Here are separate retards:

LAUNCH RETARD The launch retard is for the first 0-2.5 seconds. When the Dark Blue Launch/Reset wire is connected to 12 volts, the retard value is activated and is added to the retard sum. When 12 volts are removed from the Dark Blue wire, the retard value begins to ramp up to 0 over the programmed time. Once the time is over, the retard will not be activated again.

STEP RETARDS
There are three step retards that are controlled through three corresponding activation wires or through rpm.

GEAR RETARDS
This program provides the ability to create a run curve for each gear. Up to six different curves can be programmed from 800 12,500 rpm in 0.1 increments for every 100 rpm. The number of gears is adjustable under the SHIFT menu, as well as the amount of rpm drop the ignition needs to see before knowing that a different gear has been selected. Up to six gears can be programmed. You can also use the Step Retard wires as Gear Select Indicators for the first four gears.
These retards are mapped out on the Gear Retard chart of the Graph View. In the chart, go to the View pull down menu and select Trace Box. That will give you a small window to show the different color gear traces so creating a different curve for each gear is easier. If you want the same retard curve for all gears, compose the curve, select the Edit pull down menu and copy the curve, then select Paste All.

Hope this helps.

STAGE3
06-06-2006, 09:22 PM
lets say you pull out 2 in first gear and 2 in third do you have a total of 4 at the end of third ?:o

Eric David Bru
06-07-2006, 07:52 AM
It is my understanding that once you pull 2nd gear the 1st gear curve no longer applies. So you would still have 2* pulled, not 4*.

Once you change to 3rd gear you will have to put in a gear retard for that gear or you will be at full advance.

The curves are not cumulative as far as I know.

msdtech4
06-26-2006, 12:00 PM
You are correct you would need to plot a curve specific to that gear. The gear curves do not accumulate so if you need a certain amount of retard make sure you plot that in each gear.