MSD Retard...anyone using it???
 

I'm thinking about picking up an MSD retard system for the SC. Anyone using this? I'm curious as to your impressions of how it has performed for you.
TIA
Pat

Yes....but why would you want an ignition retard for a normally aspirated SC engine? It won't retard a single degree without a boost signal.

I have a boost signal generator installed on the SC...Borg Warner T04B H-3 trim. :)The former configuration with the old Rajay may have had detonation issues. I want to be able to retard the ignition.

http://forums.pelicanparts.com/uploa...1257553754.jpg

Patrick,

Just wondering, dose the turbo blow through the metering plate or suck through it?

How are you getting enrichment on boost? Do you have a Turbo WUR on it of some type?

Thx

Boost signal generator....I like that! I've got one too!!

There are a few of us using this method to gain some ignition advance pre-boost. They work just fine and can retard as much as 15 degrees off your timing. Some experimentation is needed to tune when, how much and at what rate you want to retard, but they're really quite straighforward. If you're already using an MSD6AL for your spark, then simply purchase the boost timing master 8762 and hook 'er up!

The SC system passes throught the top section of the airbox, and goes up through the metering plate, which is opposite the 930, I believe. I am attaching a photo of the SS airbox and the tubes. It works pretty well, but it was not engineered to do this, so I have done a lot of tweaking the past few years. I have BL WUR and RPM Boost Controller. I have two fuel heads I have used; IA is way overrich, and the stock late SC is a bit lean on top. Of course, I have a stock SC distributor, which is why I want to use an MSD retard unit.

Mark, that is almost exact to the word what the MSD tech told me today...just put an 8762 on it!


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Pat i was using a MSD BTM on my Sc engine with 9lbs of boost. i had it set at (I think) hard to remember just under 1.

Hey Chappy!
I'm going to be at 5.8 PSI on the new setup for now. I was running 26 degrees total advance on the SC distributor, the car ran like crap on less.
The only thing left of my BAE is the boots now.
Got that tub of yours running OK?
Pat

Actually just got the bugs sorted out of it tonight, i was having an intermittent ignition loss, after tons of checking wires i finally found the one with a back connector.
So i am officially all systems go, BLAST off......

"The only thing left of my BAE is the boots now."

I remember when that is all i had left on, now all i have left is the instruction manual.

How about boost retard with individual cylinder knock retard and a bunch of other stuff?

MSD tech's have been kind enough to send a few sales our way when the customer asks them for a knock controller.

Well aware of your system John, hope to have one someday....

John:
I sent you an email a few months ago. I'll resend it again from work on Monday (it's in that computer).
Pat

Just put a MSD 6AL and 8762 on my car. Driven it only a couple times, I put the knob in the car in between the seats.

Opened the plug gap to .040"

You can feel the power change and hear a difference in the exhaust as you turn the knob while accelerating.
I havn't played with the threshold adjustment on the box yet. It's set at 3psi. I want to try it at 5psi

With 7:1 compression I don't think you need to start retarding timing until 5psi in the cooler air.

I like it

J,

Cool!

The MSD effect should be most in the lower RPM's where it is most difficult to fire with the low effective compression ratio. More total power should come from more ideal timing advance.

It is great to hear your car responds significantly to more advance on boost. I have always suspected there is some solid gains to be had with a 930 on the ignition side that most are not accessing.

Seems like if the non-retarded timing settings are near there ideal you would not need a boost threshold hurdle before the MSD starts retarding. EFI guys that pull up to and more than 40 deg advance on cruse pull back timing very quickly when intake vac starts to go away. Delaying the boost level where retard starts should only be necessary if the off boost timing is not at its peak or ideal level.

I guess you could turn up the boost retard on the MSD to add protection. Then start increasing the advance at the dist until pre boost is at its best. Then start pulling back retard at the MSD to dial in the on boost power.

As total advance is sensitive to ones AFR's, it is interesting to me that one of the weaknesses of CIS where is goes a little fat in the middle of the RPM range might actually balance out a motors natural tendency to be more sensitive to total advance it the same area of the RPM curve.

Your findings would be nice to have on the CIS timing thread for those that follow.

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/500986-ultimate-930-distributor-advance-retard-timing-turbo-lag-msd-mod-thread.html

The best!

In my case, I have 8.4:1 static CR, so I am not as boost dependant. I still run stock SC distributor, basically a stock SC ignition system. I believe all engines love advance, just that our combustion chambers are not optimum for flame front propagation, hence the twin plug variant. So, for the little hemis we have, advance = piston death. I believe John's system takes the guesswork out of how much advance can be safely run.

As I've been known to say, there are benefits to the MSD advance/retard scenario. I've had no complaints over the 2+ years that I've been using it. Still working on finding the optimum settings, and since my adjustment knob is not in the cockpit as is Jim's, it's not quite as handy to just dial-and-go on the fly. I believe there are 3 or 4 of us now using this technology...collectively we'll come up with the optimum.

Well, I just decided to go with the J&S Safeguard. I believe it takes the guessing out of detonation threshold. I suppose I can advance at my stock SC settings, and let the Safeguard reign in the advance when I get to unsafe condition. One problem I have found is that I can't hear detonation from my engine...it's a loud car, and especially at the track, with a helmet and that engine screaming, I can't hear a thing. May as well implement some modern technology to supplement my stone-age CIS.

I will let you all know how it works out, if I ever get my car back together.

Mark,

You certainly have.

There are three different benefits I think I see here.

Two possably from the MSD effect.

First it has the hot multiple sparks that help ensure the lean AFR's that come with CIS under low effective compression pre boost can be ignited.

Secondly, it allows for a hotter spark on boost where the high effective compression ratio makes the mix hard to fire. (This can be had from hotter CDI non stock system other than MSD.)

The third is from a more ideal timing curve (also available from a non MSD system.)

All good stuff.

How much is from the MSD who knows. I suspect much of it is achieved from a more ideal timing curve as the stock Porsche system is a pretty hot system to begin with.

I suspect if we could find a non-MSD programmable system that uses MAP and intake air temp inputs, we could make a significant amount of improvement to.

Pat,

What type of system dose the SC dist use? Is it a vac-advance-pot?

If so, how much advance comes from the vac advance and what is the total advance run?

The early euro 930's used a vac-advance system. At idle there was no Advance as it was a ported connection. Of idle at low load the vac-advance would pull timing up to -26 or -29 depending on setting. Then with acceleration vac advance would go away and pull back timing back about 10 deg.

Not an expert nore even know much about the aftermarket knock sensor systems, nore do I want to get into a debate/discussion on it. However, I would not trust it as my main way to achieve boost retard. I would think of it more as a modest level of back up should the basic setting be off.

I believe that when Porsche added knock sensing to there system, one of the changes they found necessary was to change the style of chain tensioners and create a hard mount bridge or something across the cylinders for the sensor to deal with the noise/static that comes with an air cooled motor. Much easer to install on a water cooled motor with a solid block/cylinder config. Otherwise false reads might cost one timing un-necessarily.

Cost of doing the whole MSD conversion was a factor for me.

I bought the MSD 6AL box used in new condition here on Pelican for $150, and the MSD 8762 boost retard box which was new and never installed off ebay for $139.
The MSD epoxy encased blaster high vibration coil was about $50 new so the whole thing was about $350.

Both the 8762 and the 6AL came with long magnetic trigger cables with black shrink tube on them.
You only need one of those cables to hook up to the green coax distributor wire so I used the other to lengthen the identical cable for the adjustment knob to reach inside the car between the seats.

It works really well.

I roll up the windows and close the sunroof when listening to the engine for detonation. I know the sound.

If you don't make it detonate continuously while intoxicated in the red mist... I don't believe the rings will break or melt the edge of the piston crown next to the exhaust valve.