tsalgado

Has anyone upgraded to an MSD 6AL ignition? I am looking at upgrading my 85 Carrera and want to know if it is worth my time and money.

Dean

I did it on my 930 motor. If your CDI is working fine I wouldn't do it.

A930Rocket

I did it on my '81 ROW SC. It idled better and seemed to help some.

I've also done it to my '87 930 for the same reasons.

A before and after dyno test would have been nice though to see any improvements if any.

Jim

Sameer

Go to the top of the board and do a search on "MSD" and you'll see all the threads on it. It's a good upgrade from the stock.

D

I did it on my 930 to replace an unrelaible Permatune. If you get it you should also get the High Vibration Coil (only one recommended for upside down mounting) and the tach adapter. One thing to keep in mind is its size. Its big and does not fit in the stock location easily. Lots of people seem to put them under the drivers seat. I ended up making a bracket and mounting it on top of the airconditioner pump.

NineMeister

After being involved in a University project looking at ignition performance the conclusion we came to was that, in laymans terms, the best ignition system for any engine has one, great, big, fat spark. Once the fuel immediately surrounding the plug has started to burn, no amount of additional sparks will make a difference, so all the spark energy is best used in the one hit.
The only advantage we could find to multiple sparks is if the mixture is so rich that it wets the plug there is a chance that one of the following pulses may strike the spark, but that is all.

The 85 Carrera uses a TCI coil unlike the earlier SC with its CDI system, in my opinion you will be better off making sure the stock system is perfect rather than wasting your money upgrading to something you do not need.

D

The MSD only provides multiple sparks below 3000 rpm, above 3000 there is not enough time to provide more spark. Multiple Spark is really misnamed and should be considered as a longer larger spark, the time were talking about can be measured in milliseconds. The MSD also allows you to run a larger spark plug gap (.04) which does make a larger fatter spark throughout the rpm range.
Twin plugging is the best way to get better combustion since it provides double the spark and more even flamefront. By igniting the mixture on both sides of the cylinder, the burn time is quicker and the pressure against the piston is evenly distributed and provides a marginal power increase.

A930Rocket

I read recently the 930 pistons were "flat topped?" and didn't really affect the flame front.

But then again, I've ALWAYS heard twin ignition is better.

Jim