To MSD or not to MSD
 

I've read so many posts about MSD improving idling and low end torque that my interest was piqued. The 101 projects book recommends highly for all years.

I've also read a few posts today about MSD and late model 911s (mine's an '87) with Mototronic, saying that it's apples to apples and not a good investment unless your Bosch unit has bit the dust.

My objective would be to improve low end torque, mileage and emissions.

Opinions?

Thanks!

I've heard from a few people it improves motronic cars:

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/443697-msd6al-protomotive-3-2-turbo.html

That's great. Renewed my interest, especially when I read through the bottom post describing all the MSD wires that needn't be hooked up because of the Mototronic.


Thanks Spence.

I just converted mine (81SC) and I don't "feel" any difference from the Bosch unit. I do like the soft RPM limiting feature of the 6AL unit. And the fact that it's new and not 30 years old makes me comfortable. The multi-spark feature under 3K is a benefit for carb equipped engines that run rich but for a FI engine, you might not notice any difference.

look at the M&W pro-10. made in aus. i have no direct exp w/this unit, but when my bosch goes out i was thinking about this one

He lives in Seattle. Can buy MSD at tons of locations if it ever goes out. Why would he install some obscure system made in AUS.

I run an MSD. works great. no issues. Didnt really notice any difference over the old one.. but I was running a 15 year old Permatune.. so it was time...

you can run .040" plug gap with the MSD and should not do it with the Bosch or you risk blowing it

besides carbs and MFI the MSD will help a beat engine operate

But you can run a 0.060" plug gap with your Bosch system as long as your cap, rotor and cables are rated HEI ( high energy ignition ) components. In fact, my 86 3.2 has been on 0.060" plug gaps for over 20 years with the stock Bosch DME ignition system that has never had a problem firing them with HEI components.

As far as I can tell, I can see no advantage to retrofitting MSD over your stock Bosch system since the weak part of the 911 ignition are in the secondary components and not the system itself.


Cheers,

Joe
74 911 w/ 86 3.2

When you say "secondary components" to which do you refer?

I was thinking that the multi-spark under 3K rpm would help emissions and may improve torque, as several have attested.

I guess YMMV is really appropriate here, eh?

Are you still running this setup?

http://forums.pelicanparts.com/porsche-911-technical-forum/291853-jeep-cherokee-cap-rotor-3-2-a.html

well its settled.....if YOU run an msd then he should too

I never said that. I replaced mine because it was a 15 year old permatune, not because it was bad or because I needed better performance. I surely wasnt going to spend 1,500 on a new bosch unit (didnt have a core) or 500+ on a new Permatune. If I was running Bosch... I might not switch. All I said is... IF he is going to switch.. then it should be MSD not some obscure company in AUS that isnt readily available when the unit stops working in the middle of a DE weekend. The MSD has been great. No issues. But I had no issues with the Permatune either. Does it run cleaner? Idle better? Have better response? I have no idea. I threw out my CIS system so I have way to much going on to be able to determine the impact of the MSD alone. What I will say is that if you are running Permatune or Stock 6 pin Bosch, it was an easy conversion and works fine. If you are running Bosch... Not sure you will be any better off... you can easily get the Bosch rebuilt...

Yes, still on it. No reason to degrade to less than HEI, which is what would happen if I went back to the original Beru wires etc.

The Cherokee distributor cap and rotor I'm using are identical to the 3.8 Ford Taurus and are also HEI rated.



JPaul, secondary components are your cap, rotor and ignition wires and plug connectors.


Joe

Upgraded my Bosch CDI to the 6AL based on the 101 projects book. Worked fine for near 5 years. Then gave me odd problems where it would not work I.e restart after an initial start up. It wud simply not start reuse, unless a half hour to an hour cool down period was allowed. Caused me havoc troubleshooting it.
Location was similar to the Bosch CDI, so I cannot understand why it could not last as long as the original Bosch. Due to this problem, I refitted the original Bosch which was as old as the car. (1982 911sc).

Worst of all, there was no discernible difference in performance of the car. Plug gaps were adjusted to msd recommendations. Power was derived direct from battery. Yet no improvements showing it as a so call upgrade.

Nevertheless if a replacement was indeed needed for an unserviceable Bosch CDI, then the MSD is a financially worthy replacement. As an upgrade however it is not. Nice selectable rpm limit. Good soft rpm limit, but no improvements in car behavior thou. If fact I think the Bosch cold starts better actually. My $0.02.

I have been using the Bosch in my 1973 for 12 years no problems. I have Pertronix instead of points and I am very happy.

I have read so many MSD threads here about tach problems, rotor problems etc...and they span years. I have to wonder why there is not a better alternative to MSD that is better suited to Porsche. MSD seems to be so generic that the Porsche owner has to do lots of work to make it work well.

Replacing any ignition will only have HP results if the original was lacking in some way. I have run MSD's before on US Hot Rods and have never seen the huge benefit. They draw quite a bit to get them to work and there are other alternatives in any Summit or Jegs catalog.

Again using the US as a reference switching a standard Chevy HEI coil seams to provide the best bang for the buck so I would guess that the same would apply to Porsche. D.U.I makes or sells coils that genuinely show a difference.

The more radical the engine and on the edge of proper combustion will show the biggest difference. If you have a perfect AFR already where are you going anyway unless you are going to alter something else to make require the MSD. Again adding ANY aftermarket HP component will require others to work in a system to provide any benefit.

That said if you are looking for a cheap alternative to stock at under $200 it is a bargain and has room to grow into.

WANNA, I have to agree with you 100% . I am using the stock Bosch unit and it has been great. I did upgrade the rest of the system with Pertonix to replace the points, and a Nology M75 coil that is made for CD ignitions. It is a beefy transformer type coil and made a big difference. I am also running Nology wires.

I do have my MFI well dialed thanks to using a good AFR instrument [the Daytona-Sensors Wego IV], and replacing my thermostat cold start with a manual system.

That said, I am going to look into getting a CDI eventually that has a built in spark advance so I don't have to rely on the mechanical part in my distributor. I am studying one now.....it is not an MSD by the way. I will post something when I am done with this quest.

Bosch is a good reliable unit imo

MSD sells a tack adapter unit that works

the old rpm limiter rotors seem to have a tendency to burn out with MSD so I use the non rev limit Bosch rotor

the MSD install is not complicated but time consuming to install from the ground up without stock wiring. Old wiring is easily disconnected and stored when using carbs. I've never did a MSD + CIS install with it's added electrics

MSD box runs hot. I installed in outside the covered elect panel

some pelicanheads have reported that the MSD multi-spark turn off may fail and keep multi-sparking over 3,000 rpm causing engine to run like crap

even though I've never had a MSD fail on hot rods, boats, or my 911 I still keep a spare + coil in the trunk

some say you shouldn't max out the timing that a 911 engine can deal with under good conditions in case bad conditions turn up and you wind up blowing the engine

I bought a new 1973 RS dizzy for cheap from a dealer. It's real cheap when you figure it comes w/new cap and rotor

10deg advance initial maxes out to 35
works great with low compression pistons

Not going to max it out. The new CDIs can be programmed for advance with a built in advance curve in the software. They are programmed with a computer.

Or did I misunderstand?