Programmable MSD 6AL-2 questions - Lateral-g Forums

68Cuda · #1 12-27-2014, 12:03 PM

You can add a MAP sensor input to the box and tweak advance vs. engine vacuum. It actually works backwards... you add advance, then pull it out based on a vacuum vs. retard curve. This will allow you to run more advance under low load...

68Cuda · #2 12-27-2014, 12:08 PM

Make sure to lock the distributor.

Also look a the programmable start retard function. This box has a lot of cool features.

SSLance · #3 12-27-2014, 01:19 PM

I did get the distributor locked out and got it installed in the car. I'll have to wait until I get some expert carb help to straighten my q-jet out before I can attempt to fire it up though.

I did read that about the MAP sensor. I actually have a MAP sensor on the car now that the CCC system used. I need to do a little digging to see which one it is and if it will work for this application.

I'm pretty stoked about being able to fine tune the ignition side with this box, should be fun.

Transferring the file to the MSD...

The basic timing curve I'll start with to get it running.

SSLance · #4 01-03-2015, 11:37 AM

With the factory ECM and harness out of the way, it looks like the new MSD box will slide right into the pocket the ECM used to set in and the wires will feed right out the same hole the CCC harness used.

Does anyone see any issues with me just sliding the MSD box into this slot in the plastic kick panel to hold it in place?

It almost seems too simple and easy...

There isn't room in the slot to put the rubber feet the MSD box comes with though, the box itself just barely fits into the plastic pocket. Not sure if the box creates too much heat for the plastic or if the plastic will transfer to much vibration to the shell of the MSD box? I can't imagine either being a problem though as the box is digital now and the factory ECM has been riding in that slot for 30 years now with no issues.

Che70velle · #5 01-03-2015, 05:46 PM

Lance, i ran MSD in my racing days, and I'll tell you, I always had a spare one in the hauler, wired up with quick connector, ready to go. I can honestly say that I had more MSD box failures, than I had flat tires, in all the years I raced. If I were you, I'd get a spare box, and have it ready to go.
I ran the 6ALN box, which never really got hot. I'm not sure about the particular box you have, as far as heat goes, but I'd think that there would be ventilation in the kick panel area? I don't feel that vibration or harmonics should be an issue from the plastic panel. If you strapped it directly to something metallic, that would be a different sermon. I like what your doing with your car this winter.

SSLance · #6 01-03-2015, 07:12 PM

Thanks Scott. MSD says in their instructions that they do not recommend installing the box in an enclosed area like a glove box. This area has open slots on the top, bottom and toward the firewall for air to circulate through but would have plastic right up against the top and bottom of the box. With the box being all digital I can't imagine vibration or heat being an issue...plus it'll be a much nicer environment for the box there than out on the inner fenderwell.

I'll probably wait and ask the MSD tech on Monday before permanently running the wires but I think this is where it's gonna end up.

SSLance · #7 01-05-2015, 07:40 AM

Looks like MSD approves of the spot...

Quote:

Originally Posted by msdtech1955

that wil work out fine... if the ecu was mounted there ...I really don't see any problems.

SSLance · #8 03-09-2015, 06:08 PM

Alright, an update... I've had the car running again for about a week and man, what an improvement in horsepower so far. Haven't had it back to the dyno yet but my butt dyno approves so far.

I ended up plotting the retard curve to 7* advanced at idle (20" vacuum) and a pretty linear curve starting at 1000 RPM at 7* ending at 32* advance at 3000 RPM. I believe it would actually like a little more timing on the top end and a little less timing at idle but the box is limited to 25* of retard so this is the happy medium so far. It runs great, starts great, idles great, and I haven't heard even a hint of detonation anywhere and I've tried to get it to ping.

Quote:

Originally Posted by 68Cuda

You can add a MAP sensor input to the box and tweak advance vs. engine vacuum. It actually works backwards... you add advance, then pull it out based on a vacuum vs. retard curve. This will allow you to run more advance under low load...

Okay, I have a 1 bar MAP sensor hooked up to the box and manifold vacuum...but no boost retard curve plotted yet. This is where I need a little bit of laymans help once again helping me understand vacuum advance and how to use it to better the performance from my car.

I finally have almost gotten used to thinking about timing advance in reverse with this box...but vacuum advance, boost retard is still real foggy to me...not to mention how to set it up to work best in my situation.

Here is my graph at idle as it sits now.

and like I said it's pulling 20" of vacuum at idle

When I had the initial at 10* it was idling at 1100 RPM and pulling 23" of vacuum.

Can anyone help me with a easy to get tutorial on how to set up a boost retard curve that will help this engine using the MAP sensor?

Or just tell me what I need the MAP sensor to tell the box what to do...where and when do I want it to add advance and where and when do I not want it to add advance?

If someone can help get that through my thick head, I believe I can figure the rest out. I have to say, it was pretty effing cool to grab a dot on the graph, drag a line, and hear the engine change when responding to the change I made. I really dug that. I believe I could do the same with the boost retard curve, I just need to understand exactly what I'm trying to do first.

Thanks...

68Cuda · #9 03-10-2015, 12:23 AM

Quote:

Originally Posted by SSLance

Or just tell me what I need the MAP sensor to tell the box what to do...where and when do I want it to add advance and where and when do I not want it to add advance?

Overall adding vacuum advance will make the car run better under "normal" driving and have no effect on performance under full throttle.

So your MSD boost graph in the menu is in PSI. 14.7 PSI at sea level is 0 vacuum... every 1 psi = about 2" of vacuum. So, 10" vacuum is about 10 PSI and 20" vacuum would be about 5 PSI... now, if that does not confuse you, the graph adds retard, not advance. So, not only is the pressure graph kind of backwards to conventional thought, so is the advance.
EDIT: I think this is because this is usually used for BOOST retard... for example 10PSI boost (only airplanes use inches of boost) would be 24.7 PSI absolute. 14.7 PSI absolute pressure is no boost AKA 1 bar, AKA 0" vacuum.

Make sure you have the correct MAP sensor (1 bar) and the setting for that is correct on the MSD.

So, if I want 15 degrees advance at 20" of vacuum, I set 15 degrees more initial than previous, set my retard to 0 for anything up to 5psi, then slowly ramp in 15 degrees of retard all in by 14.5 PSI. This would give you a linear 15 degrees of "advance" from 0 to 20". What is the best curve - I don't know. I think the stock distributers can give you somewhere around 20 degrees at 20". I would start with, maybe 14, see how it likes it, progressively try more. This will cause you to have a higher advance while at idle, but that is OK, it will idle a little smoother, take less throttle screw and be less likely to diesel when you shut it off.

SSLance · #10 03-10-2015, 05:18 AM

Quote:

Originally Posted by 68Cuda

now, if that does not confuse you, the graph adds retard, not advance. So, not only is the pressure graph kind of backwards to conventional thought, so is the advance.

Quote:

Originally Posted by 68Cuda

So, if I want 15 degrees advance at 20" of vacuum, I set 15 degrees more initial than previous, set my retard to 0 for anything up to 5psi, then slowly ramp in 15 degrees of retard all in by 14.5 PSI. This would give you a linear 15 degrees of "advance" from 0 to 20". What is the best curve - I don't know. I think the stock distributers can give you somewhere around 20 degrees at 20". I would start with, maybe 14, see how it likes it, progressively try more. This will cause you to have a higher advance while at idle, but that is OK, it will idle a little smoother, take less throttle screw and be less likely to diesel when you shut it off.

I don't think I want any more advance at idle...do I? The throttle blades are completely closed and it's idling at 14.7:1 AFR at 850 RPM. Any advance at idle I add just increases the idle RPM and vacuum. I guess I could start fiddling with the idle air screws to dial them down, but am I just chasing my tail here? Heck I was trying to get the initial down to 6* to try to slow the idle down a bit more.

It's good like it is. It drives great, no issues anywhere. Maybe just a bit of a stumble when lugging it with the primary side about half open, but giving it just a bit more gas clears that right up.

I guess maybe that means it wants a bit more advance say at 1000-1500 RPM with high vacuum...right? and as soon as that vacuum drops (throttle opens) take that advance away so it doesn't detonate.