MSD..Yes or No?.....

[dhoward]

Originally posted by jmz
MSD, great with a car with carbs but why would you really need it on a properly tuned stock CIS car?

You probably wouldn't.

[H20911]

You really would not. Once the flame is lit it really would not matter if you put more sparks behind it.

MSD only gives multiple sparks up to 3K which would explain why cars idle better (particularly if they are not tuned perfectly).

If MSD was so great it would be on evey car. I only chose crane due to its digital functions and more features that a stock ign would not have.

[jmz]

It was more or less a rhetorical question. I have to say, I like my msd on my modified 3.0 though.

[RoninLB]

Originally posted by jmz
It was more or less a rhetorical question. I have to say, I like my msd on my modified 3.0 though.

it should help out a old rings and valves below 3k..
it did on a beat 350 Chevy

[MikeBogue]

Originally posted by 47silver
i have the msd and after i installed a pertronix and never (knock on wood) have trouble starting the car.

the po put the msd in and i put the pertonix....

no experience with the bosch.

gary

I would check out that pertronix a little closer. I had one in an old Volvo and I found an 8 degree variation if I rotated the magnet on the distributer lobe. I ordered another magnet assembly, because they said they never had that problem and that assembly had a 10 degree variation.

[fred cook]

To try to answer some of the questions posed above:

Does a Porsche CIS in good working order run well? Certainly!

Did Porsche and Bosch spend lots of time and money designing the stock CDI unit? Of course!

Do Porsche or Bosch EVER do anything halfway? Of course not!

Was the original type Bosch CDI designed over 25 years ago? Yep

Has there been any progress in electronic component/ignition design since then? I hope so!

Is a "rebuilt" unit better than or as good as a new one? Good question.

As much as I respect the engineering that went into not only my Porsche but also all the others, sometimes I like to "see" if there could be an improvement made. If the opportunity presents itself, the change can be made without ruining anything and the price is right, then why not give it a try? In this particular case, the original CDI went "belly up" and a repair is required. The cost of a rebuilt Bosch CDI is fairly expensive running anywhere from $250 up to $400. The Perma-tune which seems to be a fairly close copy of the Bosch unit (with some power upgrades) is also in the $300-$400 range. The MSD and the Crane Hi6 units offer the benefits of a CD type ignition with extras thrown in. The low (under 3000 rpm) speed multi-spark design should be beneficial and the $200 price tag makes it an attractive choice. Plus, as I said to start with it can be installed without "butchering" the wiring system. The last plus is that now I can also send the Bosch unit off for repair and keep it on the shelf as a spare!

Fred Cook
'80 911SC coupe

[Lorenfb]

Check out this web site (www.systemsc.com) on the Technical page
under Ignition Systems for some additional info.

[Lorenfb]

The HC (hydrocarbons) level, a measure of unburned fuel, can be used
as a comparative indicator of the effectiveness of an ignition system.
Since the HC level is a key emissions test parameter, the use of
multiple sparks to reduce the HC level by major OEM car manufacturers
would be universal. Also, if the claim for added performance were true,
this would be another benefit of using a multiple spark system.
The added technical complexity and cost of utilizing multiple sparks is
very minimal. Thus, based on these key facts, a multiple spark ignition
system has little to no benefit over a single spark ignition system.

[Oldporsche]

If I had the perfect world of a perfectly tuned digital fuel injection system, perfectly matched to the cam and timing, pehaps with variable valve timing, etc. What ever ignition system designed to go with the above would be the only way to go.

Unfortunately, this isn't a perfect world, and those of us with carbs can only have reasonable hope of an rpm range that they will perfectly work in.......the MSD often helps the carbs.

Good luck,
David Duffield

[fred cook]

First let me state that I appreciate very much that so many of you Pelicanites have taken the time to post replies on this thread. Also, I fully support the fact that everyone is welcome to their opinions, but..... I can't help but believe that some are missing a very important point here. That is, the ignition system that Porsche chose to equip my 1980 vintage automobile with was developed somewhere along about 1973 or so. That make the technology approximately 30 years old. In this day and age when an electronic gizmo (i.e. computer) can become obsolete in 6 months, I simply have to believe that improvements in ignition systems have been made since the Bosch CDI was designed. Since the CDI unit in my car has ceased to function, I have spent a fair amount of time researching various options available as a replacement. I will say that had the CDI unit in my car continued to function, I would have simply left it alone since the performance was quite satifactory. However, it failed and that has provided me with the oportunity to try something new. Since my wallet is not fat enough to change over to a distributorless system, I am limited to trying to make my remaining hardware work as well as possible. The $200 or so that this mechanical adventure will cost is both affordable and expendible. That is, if for some reason I simply can't stand the way my car runs with the MSD ignition, then I will move on to something else. One of the BIG pluses that I see is that I will still have the Bosch CDI box, should be able to get it repaired and will have a working spare on the shelf. Meanwhile I will have my car back on the road where I can enjoy it to the fullest.

Thanks,

Fred Cook
'80 911SC coupe (soon to vroom, vroom)

[H20911]

Fred.....pick what you want...I read an article in Hot Rod that did a comparison between Crane and MSD and I think that Jacobs was in there too. The out come was a huge eye opener where all the tests were within 1 % of each other. this did not shock me ( because of advertising $$$$). features such as start retard, nitrous timing retard, Boost retard....etc are the only reasons other than $$$$. MSD will work great for you and I hear if the box craps out you can send it to MSD for a total rebuild for about $60.00 ...quite a bargin indeed

[A Quiet Boom]

Originally posted by Steve W
Soft touch - sounds like a good thing for the rod bolts

Yes, This is an awesome feature and one of the main reasons MSD boxes are in the majority on drag and circle track cars among others. Simply put the "soft-touch" system pulls the spark from a different cylinder on each rotation to slow down the engine without allowing the cylinders to overfill with fuel which can be very bad. On drag cars a two-step or three-step box is used. My drag car had the MSD 7AL3 box with three rev limiters. I used the primary for max engine rpm, the second for regulating my burnout rpm and the third for launch. A launch rev-limiter is also know as a "stutter-box" because that's the way it sounds. Here's the rundown on how they're used, I think you'll see why they are so well liked. At the starting line in a stick-shift car the driver engages the starting line rev limiter, pushes in the clutch and FLOORS the pedal, the rev-limiter is usually triggered by a button on the wheel or stick shift, when the tree drops the driver just releases the button and the clutch at the same time, the engine is at the chosen rpm (usually above 5000rpm) at wide open throttle so the launch is brutal yet deadly accurate. If you think that's crazy I know some guys who also launch with stage one of a multistage nitrous system engaged still being held by the MSD soft touch. In other words if it can protect those high dollar engines and safely hold them at speed it's going to be real gentle to your P-car! Another feature that most racers like is that the rev limit is set with "pills" corresponding to the correct rpm so theire no need to free rev the engine while looking at the tach to adjust some stupid little knob.

I've used MSD on nearly every car I've had in the last 15 years with the exception of my brand new Ranger 4x4 and it will eventually get one as well.

As mentioned elswhere in this thread to mount the coil in the stock location you'll also need the high vibration coil which can be mounted upside down. Here is a pic of my install.



The box on the back wall is the Programmable timing computer, I locked out the stock advance in the distributer and use the box to set the advance curve that works best with my modified Zeniths (36mm venturis on my SC engine)

[JackT]

Fred,If I were in your shoes, I would replace with a modern, reasonbly priced aftermarket box. I misunderstood earlier in this thread. I was thinking you were pulling a healthy stock box and replacing with a MSD. My point was it would not make a huge improvment over stock. I think the MSD and other modern systems are better than stock and a lot cheaper. I run the MSD 6AL on 2 V8 engines and love it. I never foul out plugs with the MSD. They idle better but there is not a perfomance gain with the MSD over the stock setup, when the stock setup is properly tuned. The stock setup just didnt stay properly tuned long, without the MSD.

[jmz]

QUOTE:..."I can't help but believe that some are missing a very important point here...

not really missing the point, you asked a yes or no question. My opinion is that there isn't really much benefit to the MSD over a stock Bosch CDI unit on a properly tuned CIS car.

On a nasty fuel spitting High Compression Carbeurated car I think the MSD helps. ...these cars are harder to keep in perfect tune than a stock CIS car and the MSD compensates for that.

QUOTE: "Was the original type Bosch CDI designed over 25 years ago? Yep

The MSD 6AL is over twenty years old itself

QUOTE: "Has there been any progress in electronic component/ignition design since then? I hope so!"



The MSD isn't what I would call a technological marvel or even a modern ignition system. The MSD 6AL is over twenty years old itself.

I think the MSD 6al is a decent spark box and has served me well. I don't think there is a need for it on a stock CIS car and I would just plug in a BOSCH box. This way you don't have to drill any holes, make a new wire harness or worry that your MSD craps out on you down a lonely stretch of road.

[fred cook]

JMZ

How bout posting a picture of the 37' Yawl. I bet it is a real looker!

Thanks,

Fred Cook
'80 911SC coupe

PS I really wasn't trying to argue those points, just present my train of logic.

[Early_S_Man]

Fred,

All of the MSD 'advocates' seem to be in a bit of a 'cloud of confusion' ... comparing a new MSD installation to a stock CDI system with problems -- that they chose not to fix!

As jmz points out ... there is no improvement in power or drivability over a stock CDI system with clean grounds and power connections, and good trigger (green) cable, and good ignition cables ... all of which are usually done with the MSD downgrade [almost] everyone raves about!

JWW has had good luck with the Permatune unit for SCs, and I have no experience with that six-pin box to say yay or nay about it!

My best guess is that it would take under two hours to fix your Bosch CDI ...

All we are talking about is replacing the following $1.00 2N3055 transistor, and replacing some 20 or so solid point-to-point wires with new ribbon cable for resistance to fractures in the future.

[jmz]

Fred, You don't have to encourage me much to talk about boats.

Here are a few pics of SHARED WATCH.

...to keep it sort of on topic, their is nothing better for me than driving my old loud car down to the bay to go for a sail.

[fred cook]

Wow! Nice boat. I used to do a little sailing many years ago. It is really relaxing to just sort of luff along and listen to the waves slap the hull while contemplating a bottle of really good beer!

Warren,

I do plan on fixing the Bosch CDI. However, I have this insatiable, insane NEED to "fiddle" with my car. The boxes of bits and pieces (from previous automobiles) that reside in my garage are mute testimony to this fact. Usually I will show great restraint until something (like the Bosch CDI) quits working at which time I do my homework and "create" a car project. The last such project involved replacing the main fuse holders with modern "flat" fuses. It would have been much simpler to replace the fuse blocks with OEM parts, but where is the fun in that? The important thing is to go about these projects in a way that does not compromise the reliability or the "restorability" (new word) of the car. I guess I just got to be me!

Fred Cook
'80 911SC coupe

[A Quiet Boom]

The Bosch CDI may be a great unit, but MSD is certainly not a downgrade. I'll agree that maybe they're about the same on a stock vehicle but once you start doing things like bigger cams, more compression, turbos and the like the added features of MSD become real attractive. I'd say they're a must on a serious racecar and pretty important on a hot street car. Let's face it MSD systems were designed for the rigors of serious street machines and full on race cars, calling them a downgrade in relation to a Bosch unit is a bit of an overstatement. Besides when an accident like a missed shift or broken driveline part happens would your rather trust a stock rev-limiter designed only to be used in emergencies or one that was specifically designed to be used as a tool for racing? Personally I used the MSD components in my car because one I already had them and two the programmable timing computer allowed me to tune the advance to my carbs without having an outside shop recurve my distributer. I swear by MSD and until something better comes along that is also affordable in relation to the cost of the engine I'll continue to swear by them. I lost races with my drag car from broken input shafts, fried main bearings, twisted crankshafts, shattered driveshafts, broken rocker arms, etc. but never due to an ignition failure. And after my car sat outside in the snow all winter (I know sacrelige) I rapped the gas pedal a few times and it started right up, not bad for a car with a set of carbs and no cold start circuit or chokes.

[fred cook]

Here are some pictures of the MSD installation in my SC: