Is MSD6AL suitable for a 77 Carrera 3.0?

[Bill Jennings]

Hi All,
I have been offered a new MSD 6 AL at a great price is it a suitable system for my car?
What benefits would it give me.
I am currently running standard Bosch system + standard coil + points with SSI's and GT3 style 2 in 2 out.
I assume I must use the blaster coil any advantage going pointless as well?
Will making the change wring any more out of the motor?
The car is a weekly weekender around the local mountain twisties and occasional track day chariot!
Cheers
Bill

[tirwin]

A lot of people run MSD boxes. I installed a StreetFire a few months ago when my PermaTune bit the dust.

There was a thread recently where someone with points converted their distributor and used a MSD CDI. I want to say it was a Pertronix distributor but I'm not 100% sure.

A few quick things to note on the MSD:

(1) you really should run a dedicated fused 12 gauge circuit from the alternator or the starter to the constant hot on the MSD. 10A fuse should be sufficient.

(2) I talked to MSD tech support about plug gap recommendations. A lot of people say to go to .050" gap when converting. MSD actually recommends increasing gap in .005" increments until fouling occurs. I would not go straight to .050.

(3) MSD specifically recommends against using solid core plug wires so if you have the original Berus you will need to replace them with Magnecor, Clewett or similar.

[mreid]

No fuse required on the heavy red 12v lead and don't run it directly from the alternator (starter where the Barney connects is fine).

[dicklague]

I have been down this path and can offer some advice.

For starters a good aftermarket CDI and a proper matching coil will improve the performance of your 911 over the Bosch. Remember that is 45 to 50 year old technology.

You get a much more powerful spark that will help your engine at idle and should provide better spark throughout the rev range. Also most new CDIs have a built in electronic rev limiter which is a great feature.

I have Pertronix in my 1973 and been running it for 10 years and love it. Great upgrade.

All of the other posters advice is valid on the power wire for the MSD. It can draw over 5 amps at times and needs a dedicated connection. I would use a fuse of 10 to 20 amps in this line just to be safe. There is a large gauge red wire in the bundle going to the 12 pin connector in the rear. I taped into this red wire with a fuse connector and use this to power the CDI.

I find that there are better choices than the MSD. In my opinion the Daytona-Sensors CD1 is much better. More modern design and construction. And it comes with a high quality E type matching coil. Daytona Sensors LLC - CD-1 Capacitive Discharge Ignition System for Racing


Here is a thread that compares MSD, Crane, and Daytona Sensors Bosch 3 pin cdi replacement

I know you either have the MSD or are getting a deal on it.

In addition I like to add a large electrolytic capacitor to the power circuit. A 10,000 UF 25V electrolytic capacitor at the CDI helps for RFI and adds reserve power for peaks.

[mysocal911]

Originally Posted by dicklague

I have been down this path and can offer some advice.

For starters a good aftermarket CDI and a proper matching coil will improve the performance of your 911 over the Bosch. Remember that is 45 to 50 year old technology.

You get a much more powerful spark that will help your engine at idle and should provide better spark throughout the rev range. Also most new CDIs have a built in electronic rev limiter which is a great feature.

I have Pertronix in my 1973 and been running it for 10 years and love it. Great upgrade.

All of the other posters advice is valid on the power wire for the MSD. It can draw over 5 amps at times and needs a dedicated connection. I would use a fuse of 10 to 20 amps in this line just to be safe. There is a large gauge red wire in the bundle going to the 12 pin connector in the rear. I taped into this red wire with a fuse connector and use this to power the CDI.

I find that there are better choices than the MSD. In my opinion the Daytona-Sensors CD1 is much better. More modern design and construction. And it comes with a high quality E type matching coil. Daytona Sensors LLC - CD-1 Capacitive Discharge Ignition System for Racing


Here is a thread that compares MSD, Crane, and Daytona Sensors Bosch 3 pin cdi replacement

I know you either have the MSD or are getting a deal on it.

In addition I like to add a large electrolytic capacitor to the power circuit. A 10,000 UF 25V electrolytic capacitor at the CDI helps for RFI and adds reserve power for peaks.

Where are the data, e.g. dyno tests, you were promising months ago to prove that other CDIs
provide more performance than the Bosch CDI?

"All of the other posters advice is valid on the power wire for the MSD. It can draw over 5 amps at times and needs a dedicated connection."

Actually, it can draw over 10 amps that's why the EXTRA power connection!

[timmy2]

If the price is great, just buy it and put it away in case you need it. Pertronix points and a new Blaster II high vibration coil would be the ideal addition, but you can run it with what you have.

[tirwin]

Originally Posted by mysocal911

Where are the data, e.g. dyno tests, you were promising months ago to prove that other CDIs
provide more performance than the Bosch CDI?

"All of the other posters advice is valid on the power wire for the MSD. It can draw over 5 amps at times and needs a dedicated connection."

Actually, it can draw over 10 amps that's why the EXTRA power connection!

Can we please keep the conversation to helping the OP?

There was a discussion a while back that the MSD draws 1A for every 1k RPM. So that's why I stated 10A should be fine. What makes you say it will draw greater than 10A?

[dicklague]

Originally Posted by mysocal911

Where are the data, e.g. dyno tests, you were promising months ago to prove that other CDIs
provide more performance than the Bosch CDI?

"All of the other posters advice is valid on the power wire for the MSD. It can draw over 5 amps at times and needs a dedicated connection."

Actually, it can draw over 10 amps that's why the EXTRA power connection!

I NEVER promised dyno tests. I did do bench tests comparing the Bosch to CD-1 and posted the results. And again my own driving experience with 120,000 miles of driving my 911 stock, then with Pertronix, then with the CD-1 igniton demonstrates to ME, a huge improvement.

I am not planning any dyno tests.

Here is the bench testing I did:

I did a bit of test on the stock Bosch CDI and the Daytonal Sensors CD-1 ignition.

The test setup was basic. I used a MSD spark generator which basically is a square wave generator with a digital read out of RPM. It simulates what points or a hall effect ignition setup like a Pertronix will put out. I fed this signal into the points wire in the Bosch [black wire]. For the Bosch I used a transformer E coil made by Nology it is called a ProFire and has part # PFC-M75. I have been using this coil on my 1973 2.7 MFI motor for years. It is designed for CDI.

I used Lisle 50850 Ignition Spark Tester that has an adjustable gap and a big alligator grounding clip. I set the gap to 10mm. This means that the unit under test is just one "spark plug" with a big gap.

I powered this CDI with a 500 Watt 12 VDC power supply that was able to supply 12 vdc through out the test.

To test voltage I used a General Technology Corporation TA 100 tachometer and engine analyzer. This unit can read RPM wirelessly and can read voltage by wrapping around the plug wire that comes from the center of the coil. I measured at the end of the wire closest to the spark gap tester.

This tester holds a max and min reading of each test.

With this set up I got the following results on the Bench

Bosch 3pin CDI part # 0 277 200 001

1000 RPM 10mm gap 32.4 Kv
5000 RPM 10mm gap 43.8 Kv
7100 RPM 10mm gap 41.5 Kv

DAYTONA-SENSORS CD-1

1000 RPM 10mm gap 94.7 Kv
5000 RPM 10mm gap 88.2 Kv
7100 RPM 10mm gap 81.3 Kv

the Bosch would occasionally "flame out" at 7100 RPM.

Remember I am firing 1 "plug", but 10mm is a HUGE gap to fire.

I did not have an MSD. I would imagine it would do better than the
Bosch. I do know the CD-1 135 Mj [milli joule] of spark energy output.

[jeffs9146]

I put a MSD6al in my 83sc and increased the sparkplug gaps .005 a few times until I felt I was getting the best performance.

It has run great for almost a year!

[mysocal911]

Originally Posted by dicklague

I NEVER promised dyno tests. I did do bench tests comparing the Bosch to CD-1 and posted the results. And again my own driving experience with 120,000 miles of driving my 911 stock, then with Pertronix, then with the CD-1 igniton demonstrates to ME, a huge improvement.

I am not planning any dyno tests. Should I repost the bench tests I did? Or should I do a video of the bench tests?

Bench tests don't provide performance data and the claim is more performance!
If you dislike the Bosch CDI that's fine, but don't make unsupported claims.
Again, just because an ignition unit produces more voltage than another ignition
doesn't mean that it's a better unit or more performance results, i.e. there's
a minimum voltage level necessary and beyond that of no value.

[dicklague]

Originally Posted by mysocal911

Bench tests don't provide performance data which is the claim!

So if I have 94.7 KV at idle it will be the same as 32.4?

Or if I have 81.3 at 7100 rpm it will be the same as 41.5?

Defies all logic.

[mysocal911]

Originally Posted by dicklague

So if I have 94.7 KV at idle it will be the same as 32.4?

Or if I have 81.3 at 7100 rpm it will be the same as 41.5?

Defies all logic.

Again, an ignition's voltage output is NOT a measure of what a car's performance will be!

[tirwin]

Originally Posted by Bill Jennings

Hi All,
I have been offered a new MSD 6 AL at a great price is it a suitable system for my car?
What benefits would it give me.
I am currently running standard Bosch system + standard coil + points with SSI's and GT3 style 2 in 2 out.
I assume I must use the blaster coil any advantage going pointless as well?
Will making the change wring any more out of the motor?
The car is a weekly weekender around the local mountain twisties and occasional track day chariot!
Cheers
Bill

Bill,

You asked about the difference. I can tell you that my "butt dyno" tells me I have more low end grunt. My nose says the fuel burn at idle was improved (less rich smelling). I would suggest checking your dwell before and after.

I think the multi-spark only occurs up to around 3k RPM. Any of the MSD boxes are higher energy output than the Bosch or PermaTune. I think the StreetFire is something like 95 MJ and the 6AL is around 110MJ.

-T

[mysocal911]

Originally Posted by tirwin

Bill,

You asked about the difference. I can tell you that my "butt dyno" tells me I have more low end grunt. My nose says the fuel burn at idle was improved (less rich smelling). I would suggest checking your dwell before and after.

I think the multi-spark only occurs up to around 3k RPM. Any of the MSD boxes are higher energy output than the Bosch or PermaTune. I think the StreetFire is something like 95 MJ and the 6AL is around 110MJ.

-T

More spark energy, like more spark voltage, is NOT a measure of performance.
Again, once the minimum spark energy is achieved, any additional energy is wasted.

With regard to; "My nose says the fuel burn at idle was improved (less rich smelling)",
most likely the fuel mixture was not set correctly and "smelling" hardly suffices for
a CO meter.

[Bob Kontak]

Originally Posted by mysocal911

With regard to; "My nose says the fuel burn at idle was improved (less rich smelling)",
most likely the fuel mixture was not set correctly and "smelling" hardly suffices for
a CO meter.

I remember when there was an in depth discussion a while back where you did acknowledge there could be some incremental benefit from the multiple sparks at lower rpms. I think we we actually messed with piston speed (mph) and then how many times it would fire at various rpms through the range the benefit could perhaps be derived.

Not really a big deal from an argument point. You did not say it does. You just said along the lines of maybe. Not worth rehashing.

I feel a little more crispness at low RPM's as well (6AL). However, at higher RPM's I can't say one way or the other vs my collection of failed Permatunes.

Nice thing is the MSD is 12 years old. No problems. Took me two weekends to do a full anal retentive install but I am slow. When I want to go wild I put my 7k pill in.

[mreid]

Here are the instructions. Page 19 shows you how to connect it if you use a pertronics to replace your points.

http://static.summitracing.com/global/images/instructions/msd-6425_frm29772.pdf

[tirwin]

Originally Posted by mysocal911

More spark energy, like more spark voltage, is NOT a measure of performance.
Again, once the minimum spark energy is achieved, any additional energy is wasted.

With regard to; "My nose says the fuel burn at idle was improved (less rich smelling)",
most likely the fuel mixture was not set correctly and "smelling" hardly suffices for
a CO meter.

Dave,

I think the tipoff that my methods were completely and utterly unscientific should've been the use of the phrase "butt dyno".

I knew precisely what the dwell was prior to and after switching to the MSD. If I knew of a local shop that actually had a CO meter, I would've had the CO checked, but I don't know of one.

You should look into getting that corn cob removed from your sphincter.

-T

[dicklague]

I think CO meters have vacuum tubes in them.....don't they?

How about AFR will that do? That is what we use now and there is a direct correllation and charts too.

[dicklague]

here you go for CO AFR conversions.

[dicklague]

MYSOCAL911 "................ but don't make unsupported claims." The claims are supported by my "butt dyno" and I trust that.

The 73 911 just runs much better.

I have nothing against the Bosch CDI other than it is 41 years old and a 45 year old design.

the new stuff is better.