Programmable MSD 6AL-2

[j911brick]

Does anybody use one of these? Preferably on a 3.2.


TIA
james

[scott.k]

just bought it and am about to start the install. Im on a 3.0 though.

there is a guy on the forum who runs it who said he would help me with the programming and whatnot. His user name is cole930. He knows his stuff. I recommend you talk to him.

Scott

[Sigurd]

I have one installed on my '73.5 with a modified 2.7. Works great! I got it so I was able to get the desired ignition curve without having a distributor with the correct specs.

The hardest part of the programming was to find a PC with a serial plug.

[DonMo]

Pelican Parts Technical BBS - Search Results
search msd+motronic yields many hits. good reading

[GaryR]

Originally Posted by Sigurd

The hardest part of the programming was to find a PC with a serial plug.

1-Port Serial USB DB-9 Serial Adapter High Speed 230K USB SERIAL Adapter Cable 6ft. $15.95

[scott.k]

Im a beginner with ignition timing which you will soon realize. I was wondering, on the 6530 "Run Retard Curve" map, do you set up a new map for the degrees of your crank or are you simply retarding the timing (hence the name) and adjusting the stock timing curve on your distributor. Because I just got the 6530 and the map only peaks at about 25 degrees which I believe is less than the stock setup.
Thanks
Scott

also, when one is talking about the degrees, it is referring to piston #1 at TDC, right?

[scott.k]

Originally Posted by Sigurd

I have one installed on my '73.5 with a modified 2.7. Works great! I got it so I was able to get the desired ignition curve without having a distributor with the correct specs.

The hardest part of the programming was to find a PC with a serial plug.

Could you give some detail of the run retard (im assuming thats the map your talking about).
I could use the help.
THanks
scott

[Sigurd]

Scott,

I can e-mail you the file I am using later today and explain what I have done. It is very unlikely you can use the same file, but it will show you how it works.

I'll be back.

[psalt]

do you set up a new map for the degrees of your crank or are you simply retarding the timing (hence the name) and adjusting the stock timing curve on your distributor. Because I just got the 6530 and the map only peaks at about 25 degrees which I believe is less than the stock setup.

scott,

No ignition box or ECU has the ability to wait for a trigger signal and go back in time and fire the ignition. You have to set the distributor mechanically to your max advance spec, then program the box to vary the number of degrees of retard from max with rpm and load.

[scott.k]

Originally Posted by psalt

do you set up a new map for the degrees of your crank or are you simply retarding the timing (hence the name) and adjusting the stock timing curve on your distributor. Because I just got the 6530 and the map only peaks at about 25 degrees which I believe is less than the stock setup.

scott,

No ignition box or ECU has the ability to wait for a trigger signal and go back in time and fire the ignition. You have to set the distributor mechanically to your max advance spec, then program the box to vary the number of degrees of retard from max with rpm and load.

Oh ok,
thanks
In that case, for now I would just want to set it for the timing of a stock sc distributor, right? Because I dont think the stock distributor is adjustable
scott

[scott.k]

Originally Posted by Sigurd

Scott,

I can e-mail you the file I am using later today and explain what I have done. It is very unlikely you can use the same file, but it will show you how it works.

I'll be back.

I just sent you a message but in case you check here first, my email is scott.kelley121@yahoo.com
It would be helpful if you could send it to me.

Also, above you said you were able to get the desired ignition curve without having a distributor with the correct specs.
Does that mean you did not have to adjust the distributor?
thanks
scott

[psalt]

Oh ok,
thanks
In that case, for now I would just want to set it for the timing of a stock sc distributor, right? Because I dont think the stock distributor is adjustable

scott,

The purpose of the "programmable" part is to give you the freedom of control over the timing curve. A mechanical advance is very crude and cannot be fine tuned to the degree of an electric switch. Ideally, the ignition timing needs to be set to produce max cylinder pressure at 14 ATDC. It take a fixed (relatively) time to burn the fuel, so you need to start the fire BTDC. As rpm increases, there is less available time and you need to advance the spark to peak the pressure at the same point. If the spark is not advanced enough and the pressure peaks after 14 ATDC, more of the energy of the fuel does not do work, it is wasted into heat. If the spark is too far advanced, abnormal combustion (knock) occurs, pressure spikes at the wrong time, and output drops. The 911, a hemi head with domed pistons and poor cooling, is knock limited and you will probably not be able to use the ideal timing with pump fuel. My advice is to start by copying the factory curve and only advance the max timing if you have the octane and the ability to detect detonation.


With the stock mechanical distributor, you set its position at idle to 5 BTDC, as rpm increases, the weights move out and change the position of the rotor and change the timing of the spark. You can feel the range of this motion by turning the rotor against the direction of rotation. With electronic control, you cannot set the distributor at 5 BTDC (because you can't go back in time). Advancing the timing means more degrees BTDC, so you have to mechanically set the distributor to the full advance position and let the ECU delay the signal that fires the coil. You build the advance curve by reducing the delay (retard). The words seem a little backward the first time, but it should be invisible in the program software. You also need to lock out the mechanical advance and vacuum retard, so that the ECU is the only thing effecting when the spark occurs. You also should check the phasing of the rotor to the cap towers with a cut away old cap. Since the rotor will no longer move in relation to the tower with rpm, you need to lock it in a position that will allow the spark to jump the gap. Idle timing is largely irrelevent, more will give you a stronger cold start and idle. If the rotor phasing limits the range of advance, use more initial advance.