MSD programmable thread

[9dreizig]

Hey guys. I just ordered two map 3 bar sensors WITH the connector and free shipping for $44 each from http://www dot 1aauto dot com/
Killer deal

[930_pit]

This is the boost retard curve I made the way I understand it but could be wrong.

total timing = 29 degrees

0 to 1 bar (0 to 14.7) = no retard

1 bar to 1.5 bar ( 14.7 - 22) = 0 to 0.5 bar boost - no retard

1.5 to 2 bar (22 - 29.5) = 0.5 to 1 bar boost = 9 degrees boost retard to make 20 degrees timing under 1 bar boost


Sorry for the pics, it is quite small. Photobucket is automatically shrinking it.

[cole930]

Guy's

I've got a bit of a "while you are in there" deal going. With the addition of the 6530 I'm contemplating adding a crank trigger for better timing control. The MSD's will take a direct crank trigger input from a magnetic, nonmagnetic, or Hall effects sensor. That allows you to gut the distributor down to just the shaft and rotor and eliminate any phase shift issues. It uses a 60-2 wheel and makes it much easier to check and maintain accurate timing.

I found a nice little setup that pretty reasonable.







Cole

[mark houghton]

Originally Posted by cole930

Guy's

I've got a bit of a "while you are in there" deal going. With the addition of the 6530 I'm contemplating adding a crank trigger for better timing control. The MSD's will take a direct crank trigger input from a magnetic, nonmagnetic, or Hall effects sensor. That allows you to gut the distributor down to just the shaft and rotor and eliminate any phase shift issues. It uses a 60-2 wheel and makes it much easier to check and maintain accurate timing.

I found a nice little setup that pretty reasonable.

Cole

Sooooweeet! Keep this up Cole, and you might as well go EFI. But I know, you're a purist...making CIS work as well as it possibly can.

I think I would be afraid to drive your car, especially with the 5 speed and shorter gears. I have a feeling keeping it straight down the road can be a challenge. Mine, it just does a nice rear-end "grunt" (like a dog for his first movement in the morning) when I put serious foot into it in 1st. The front end completly un-weights and I swear I'll need wheelie wheels, but still maintains traction. Probably because I'm still running with a 7006.

[cole930]

Gimp,

I'm still running the old 4 speed. It and that CIS have been together for 30 years and I'd hate to break them up.

You probably better reconsider putting that 7200 on, it may be more that your heart can take. I have a defibrillator in my chest and it will jump start me it the rush gets too great, but with you, it could be suicide.

Cole

[911st]

Is there a vac advance map function to advance timing behond WOT normally asperated timing.

That is, I am assunming the base map should be an ideal if there was no boost at WOT. (Maybe tune this map with no spring in the WG or better yet a gutted WG).

We add on top of that, retard with boost.

Can we add in advance at less than WOT at cruse?

[9dreizig]

Kieth,
There is no vacuum advance. Only retard. Therefore we will need to set the advance mechanically and then the retard will be from that point. Shouldn't be a problem as there is 25 degrees of retard possible. As I understand it the closest we get to top dead center is 2-4 degrees at start so if we have 28 degrees of advance in then 25 full retard will end with 3 degrees..

[911st]

This needs to be verifited but if it only has 25 deg of advance I would probably try to start at about 7 to 10 deg at idle and let it advance to -32 to -35 and be full in in the -2500 to 4000rpm range.

Should make it peppy off the line and with near -35 on cruse and let it still get pretty good gas milage.

Then use about 15 deg of boost retard to pull it back to about -20 at .8 bar or -19 at 1 bar.

Then tune from there.

[9dreizig]

Hey guys an update. I have mine installed (replaced my old 6A) so the only thing I had to set was the max rpm and number of cylinders. Since I'm traveling and moving the next few weeks I don't anticipate doing anything else to it for a while. I did varify that the computer was up and running, guages on the screen work etc.. Installation was easy and clean. I'm looking forward to playing with it. Oh and the DWUR is also running well and rpms all match (DWUR, tach, MSD).
The game plan is to install another MAP , so I can plot AFR vs RPM vs Boost with my LM-2

[911st]

Cole,

I am not sure you can use that type of wheel to trigger the MSD. I think you need something that sends one signel every 120 deg.

[cole930]

Keith,

You are absolutely correct. I'm having a hard time finding a 3 magnet balancer wheel any ideas.

Cole

[9dreizig]

Cole, I"m not sure of the advantage anyway. Our units are mag pick up and you'll still need the distributor to disctribute the spark .

[cole930]

My original intent was to be able to get timing into the Lm-1. The crank trigger would give me crank position but that doesn't get me a spark input I can use to
be able to calculate timing. I'm on about plan D now.

Wanted to tell you I got drug to Detroit on Fri. and got back about 1 Am Sat. I was also gone all weekend and haven't been able to send out your hose yet. I also found the charge pipe you wanted last nite. Let me know what you want to do. I should be available all week just give me a call when it's good for you.

Cole

[911st]

I have been thinking about this and have some thoughts.

Some are finding it an effort as to locking out the distribuitor or finding a trigger.

We are also limited to a total advance range of 25 deg when I belive we could use up to as much as 30 to 40 deg's of advance.

I am thinking we could concider wraping this thing around the existing mechanical advance system with the stock Pot retard functions disabled.

If we keep the stock mechanical advance in place we can program around this. This would give us about 15 deg of mechanical advance plus the 25 deg of MSD advance for up to a 40 deg timing range.


I think a starting point might be the following 'goals'.

-5 deg at idle quickly going to say -15 by 1500rpm.

Full advance of -35 by about 3500rpm with no boost. (Big improvement in motor temp and MPG).

-20 deg by .8 bar or -19 by 1 bar.

Thus, if the mechanical advance curve is a total of about 15 deg between 1000rpm and 3000rpm that is about 3.75 deg advance per 500rpm.

We could set up the MSD as follows.

Base map would start at idle at -13 (35 less 15, less 7 ). We will retime the motor at the pully latter.

1500rpm would be at about -9 (35 less apx 15, plus 3.75, less 15)

From 1500 to 3500 it would go from -9 at 1500 of base retard to 0 retard at say 3500rpm.

That would be the base map starting point.


Then boost retard map would need to be programed to able to retard from -35 total advance to -19 at 1 bar boost.

This would probably taper from a maifold pressure 15 being 0 retard and a straight line to 16 deg of retard (35 less 19) by a maniflod pressure of 30. It could continue to retard further at higher boost. We could even get more agressive at higher boost levels as a soft boost limiter.

With these programed in, we would then have to retime the ditribuitor using a timing light.

We would have to mesure off a timing mark on the pully to -35 degs.

Then timing would be set at -35 at 4000rpm with the vac line to the MAP sensor dissonected. This might require moving the distribuitor indexing one tooth.


Then with the MAP sensor hooked back up we should hit our stated timing goals and then further fine tuning can be done from there.

[9dreizig]

Kieth,
Funny I was just on the phone with Cole discussing this very thing. My question was what would happen if we lost a vacuum line going to the MAP ? The control would have no way of knowing that the boost just didn't go to zero.. So my thoughts were wouldn't keeping the mechanical retard in place provide us a tiny bit of security ??
Hey my offer to drive over with this thing and let you help me tune it is open ( or come to my place in Reno!)

[cole930]

Guys,

Unless I'm missing something here you can't do that. The original vacuum canister moves (advances) the advance plate of the distributor. To utilize the programming function of the 6AL-2 the first thing we do is gut the springs and weights and then move the advane plate to it's advance limit and pin it in place at full advance. The advance plate is no longer movable.

Cole

[9dreizig]

Ok since I've never taken one of these apart is there a seperate advance AND retard ?? My thoughts were to take the advance vacuum lines out, leaving the retard functions, which are based on inertia ?

[911st]

Cole,

My thought is to plug or disconnect the two vac lines to the pot which keeps it from contributing any retard but keep the mechanical advance.

This is just one step in between what I think you or someone here might already be doing (re Chris / 356-930) by advancing static timing for better low end and using an MSD to add more boost retard to bring timing back to a safe level -- and going full out by locking down the mechanical advance and removing the pot.


I think you are using: Higher Initial Advance + Mechanical Advance+ Boost Retard, + Vac Retard, + MSD retard.

I am talking about: Higher Initial Advance + (Mechanical Advance + MSD Base Map timing) + MSD Map retard= Total Advance.



Todd,

Thanks for the offer. My wife when there this weekend for mother's day. Did not think about coming up and doing Porsche stuff. I was more trying to get out of the woman's stuff.

It is always good to ask what if there is a failure. In this case we might ask, which has a higher chance of failure. The old Pot on the dist with out us knowing so. Or the MSD timing maps failing but the MSD keeping on working. Most likely if the MSD is starting and the idle speed is ok, everything should be ok on boost.

The way most 930's are probably set up the vac tubes to the dist are probably down sloping. This lets condensate from the motor cooling to drain moisture into the pot and make for potential corrosion. Especially after 25 years.

[911st]

Todd, the weights and springs are mechanical advance. The Pot is vac-retard and boost-retard.

[911st]

Cole,

Could you cut most the teeth off the pully you referance and keep 3 at 120 deg each.

MSD also makes timing wheels that I belive go in the dist.