MSD and other ignition systems

I read the tech article on the MSD ignition. ANyone have any experience with this on a SC? What are the specific part numbers for a 911 and has anyone else had better luck with another system. I have a Jacobs on my Jeep that performs well, but I want to look into the best system for a 911, if any.

Thanks in advance,

Olivier
82 SC

911 SCs came with an excellent, and very "hot" ignition system. I am not considering any aftermarket ignition parts because I don't believe my car needs any.

Those multi-spark systems looked attractive for a while, but my system does not fail to ignite the fuel with the first spark. If it did have a 'miss' problem and a fresh cap and rotor did not fix it, I would suspect the ignition cables.

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'83 SC

The MSD is a good system for what it is designed for; to provide significant improvement over the old points and coil system. You would have to go to something like crankfire distributorless ignition to realize an improvement over the stock SC system (which if maintained does a good job)

The crankfire is not cheep though

I am NOT trying to give anyone a hard time about whatever advertising hype they may have read that convinced them there might be domething out there better than what came from Stuttgart bolted to the console on the left side of their 911's engine compaertment. I would just like to point out that countless factory endurance racing wins since 1967 have used the SAME Bosch CDI-system that came on your car in 906's, 907's, 910's, 908's, 917's, 911R's, 911RSR's, 934's, 935's, 936's, 956's, 962's, etc. An even greater number of wins in 'customer' race cars most likely also used the same 'stock' Bosch CDI ignition, though some may have changed to something else.

Point made. Any questions?

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Warren Hall
1973 911S Targa

I have heard and think that permatune is your best bet for a P car.

The MSD 6A series is analog and the coil could give more current at the plugs but not bad choice. MSD has had to recently move up to digital to keep up.

I removed my MSD-6AL and moved to a Crane Cams HI-6TDRC unit which is their newest offering (out Less than 6 months) because it has all of the features (and many more) that I needed in the MSD set up that you must keep adding to and it is digital (read as more accurate and reliable).

Jacob's, I think, will promise the moon and the shop here in town has stopped selling them because of what they consider to be false claims regarding spectacular gains.

Bottom Line: In a street engine, once the flame starts "the burn" all the fancy stuff does not matter. So It really come down to the features that you might need (boost retard, start retard, rev limiter...) and relaibility.

So it is your choice. HIH

s

Just read Warren' post after submiting mine and your CDI set up is fine. My previous post was a comparison regarding features needed (not just wanted).

s

A agree that the stock cdi is a fine unit. One thing that the msd unit does, is provide spark for about 45 to 50 degres of crank rotation of dwell, what that means is you have spark for a very long time, giving a complete burn up to tdc ad past tdc .I would think it would burn all the gases completely?
DRD 85 Carrera

Hang on guys, if it's a motronic car, Porsche went away from the CDI at that point... My 87 has straight coil fired by the Motronic unit. I added a 6a to it, noticed few nice suprises.
1) Idles much smoother
2) Starts easier
3) More power in the rev range (guess 5-6)

The power increase was not dramatic, but you could feel it.. pretty much eliminated the flat spot around 3500-4000. I also noticed that when I added my chip, the car had trouble idling when cold, or certain other times. The MSD cured this.

In summary, I didn't see a night and day difference in power, but the drivability issues make it worth the $135 (summit) I paid.

Comparing CDI to MSD, probably would've saved my money...