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Sat Jul 13, 2013 6:52 pm

on my 1641 build i was wondering if any one has used the msd streetfire box on there vw how did it turn out perfomance

Sat Jul 13, 2013 8:38 pm

I don't have a Streetfire Box, but I do have a 6AL. Yes, the idle is a little smoother, it starts easier, and you get more complete combustion. The drawback is that those multiple sparks wear ignition components like caps, rotors, and plugs three times as fast. I would think the money spent on the set up could be used better elseware. It's a great setup, but the couple hundred bucks you spend on stuff for a complete setup, I would think you could get more bang for your buck with bigger cylinders, or dual carbs.

Sun Jul 14, 2013 6:27 am

I've never used one, but I do use CD ignitions on every old car I have but they are not multiple spark. I've heard from some owners using MSD brand ignitions that they wear plugs and caps out (by erosion of the contact surfaces) more quickly than the standard points setup. I think the multiple spark is an issue, but more importantly the fact that MSD charges its discharge capacitor to an extremely high voltage. The spark power at its peak is extremely high which spits off bits of metal every time the plug fires. The older single event CD ignitions kept the peak power lower and plugs and caps actually lasted much longer than with points while still performing as well as an MSD on 99.9% of the cars they were put on. I would still consider using an MSD brand and use the fuel savings to replace the cap and plugs every couple of years. Just don't go crazy with the plug gap (keep it no wider than 35 thou) and make sure your plug wires are good and tight and use some dialectric grease. Also, chew the resistor out of your rotor and solder in a short length of wire. The MSD or any CD will eventually take it out by the peak spark power which is higher with a CD. Fred

uncapj wrote: on my 1641 build i was wondering if any one has used the msd streetfire box on there vw how did it turn out perfomance

Sun Jul 14, 2013 12:15 pm

What plugs would you guys recommend for a 6AL? I'm not concerned about my points because I also have the MSD billet distributor and plug wires, but I don't know what to pick up for plugs themselves..

Sun Jul 14, 2013 4:24 pm

I use one heat range colder because the multiple sparks will create more heat. You also need a non-resistor plug because CDI's don't play well with resistors.

NGK B6HS #7534 for stock 14mm 1/2 reach
NGK B6ES #7432 for 14mm 3/4 reach
NGK D6EA #7512 for 12mm 3/4 reach

Or if you want a protruded electrode that burns a little cleaner,

NGK BP6HS #7331 for 1/2
NGK BP6ES #7333 for 3/4

Sun Jul 14, 2013 6:34 pm

I was going to let someone else jump in on the right plugs. Interesting that you mention not using resistor spark plugs. I used CD ignitions for many years with resistor plugs and only ever had two go bad about 15 years ago. They were Champion RL87YC for an old Volvo. Champion had started going cheap so I switched to NGK and never looked back. The two Champions that basically open circuited were from the same batch and I suspect they would have failed even with the standard ignition. The resistor in the Bosch rotor is definitely a weak link though. Fred

gkeeton@zbzoom.net wrote: I use one heat range colder because the multiple sparks will create more heat. You also need a non-resistor plug because CDI's don't play well with resistors.

NGK B6HS #7534 for stock 14mm 1/2 reach
NGK B6ES #7432 for 14mm 3/4 reach
NGK D6EA #7512 for 12mm 3/4 reach

Or if you want a protruded electrode that burns a little cleaner,

NGK BP6HS #7331 for 1/2
NGK BP6ES #7333 for 3/4

Sun Jul 14, 2013 6:41 pm

Mysterious Spark Disappearance

.

Sun Jul 14, 2013 6:48 pm

gkeeton@zbzoom.net wrote: I use one heat range colder because the multiple sparks will create more heat. You also need a non-resistor plug because CDI's don't play well with resistors.

NGK B6HS #7534 for stock 14mm 1/2 reach
NGK B6ES #7432 for 14mm 3/4 reach
NGK D6EA #7512 for 12mm 3/4 reach

Or if you want a protruded electrode that burns a little cleaner,

NGK BP6HS #7331 for 1/2
NGK BP6ES #7333 for 3/4

thanks! my heads are 12mm 3/4 reach IIRC, so I'll be going D6EA it looks like..

Sun Jul 14, 2013 8:42 pm

The MSD brand CDi are a bit too "hot" for these engines, can cause some cross-fire problems unless you have top notch wires/cap/rotor, and even then it's hard to say if it's really better in any major way.

If this is the older inductive streetfire then I don't know, but the newer ones are a CDI

Mon Jul 15, 2013 4:55 pm

Fred Winterburn wrote: I was going to let someone else jump in on the right plugs. Interesting that you mention not using resistor spark plugs. I used CD ignitions for many years with resistor plugs and only ever had two go bad about 15 years ago. They were Champion RL87YC for an old Volvo. Champion had started going cheap so I switched to NGK and never looked back. The two Champions that basically open circuited were from the same batch and I suspect they would have failed even with the standard ignition. The resistor in the Bosch rotor is definitely a weak link though. Fred

I had some carb issues I was chasing down at the same time I installed my 6AL, and thought I didn't have something hooked up right. When I was going over the setup with one of the MSD Techs, he suggested to run non-resistor plugs. He also suggested not to run the condenser if you were going to use the points to trigger the box. I've talked with people that have used stock Bosch resister rotors, and stock Bosch solid copper core wires with MSD Ignitions, and not had any issues. Then I've spoken to those that had the rotor pop a few miles down the road, and others that have tach's that no longer read the correct rpm. Scott Novak used to post on the samba, and had a wealth of knowledge about ignitions. I tried to create the lowest resistance path for the spark by using 50 ohm/foot wires, non resistor rotors/plugs, and a low turn count coil for lower voltage/max amperage. Although a 009 cap is pretty tiny compared to a V-8/MSD cap, I haven't had any cross firing with plug gaps up to .034. I usually use .032 to give the plug some room to wear.

I remember some back to back dyno tuning with the same engine here on the site. The multiple sparks, and higher energy sparks leaned the engine out slightly from the standard Bosch ignition. In turn the MSD engine was able to be jetted slightly richer, and made slightly more hp. This was on a large engine, and it was minimal, so a small engine may see very little of a change.

Mon Jul 15, 2013 8:18 pm

Thanks for that. You might be interested that I just tested a NOS Permatune today from the early seventies, one of the 'blue' ones. It has a very, very short duration spark of less than 100uS and the spark is weak. I do not even need to measure it, as I can tell by the sound and the width of the spark that it is quite weak. It also fires positively and not negatively and has a single spark polarity like the Bosch or MSD, unlike a Delta or any others that followed my late father's design theme. The Permatune voltage is limited to under 30kv at low rpm with the average coil, which is good, but the voltage drops off rapidly with rpm and the trigger circuit will not fire above 5500rpm on a V8. At 5500rpm it would not fire a plug gapped greater than 30 thou (as a guesstimate). It also uses more current than it should but it's not nearly as bad as the NOS 8 pin Bosch I have for current draw, which will trip the breaker on my power supply at over 10 amps sustained at 5500rpm. My version has a hotter, longer spark and only draws 2.5amps when the switch is selected to 12V and 3amps when the switch is selected 6V at 5500rpm (8cyl). Both the Permatune and the Bosch have absolutely no voltage control with rpm. The Permatune does have reasonably good power supply voltage control as far as variations in battery voltage goes, providing the rpm is kept low, while the Bosch does not. The Bosch output voltage varies almost directly with battery voltage which takes away one of the advantages of a good CD igntion. Also the Permatune will start and run at 5V which is pretty good and better than the Bosch, but the Bosch has a hotter(more powerful) spark. The old Hyland CDI, or my version of Lloyd Winterburn's design, is a completely different animal or so I'm finding out. I think the design philosophy with some of these others was to reduce the spark duration by making the CD pulse single phase in order to re-charge the capacitor more fully by energy that wasn't consumed in making a spark. In other words, a smaller fraction of the energy stored in the discharge capacitor is actually used to make a spark since more of that discharged energy is recovered. That way they could compromise on the power supply output and still achieve high rpm. So, the spark energy ratings for CDIs are completely bogus in more than one way. They should be talking about spark power and duration instead, and not what the discharge cap was charged to before each discharge. In the case of Permatune and Bosch, the short duration single phase spark design philosophy did not work and the weak power supply became overloaded and actually consumed more power parasitically while giving out less spark power at high rpm. I presume MSD got it right, since their units are apparently efficient, although complex. They do produce way too much available voltage, and voltage and current rise time is too fast in my opinion, and most probably the spark duration too short as well. Although I do not believe that any more than 0.5mS could possibly be beneficial on any engine. For instance, the old sixties dwell extenders used to chop the normal Kettering spark down to 100uS and nobody knew except the designers that they had a short spark! The short spark just happened to be more powerful and the igniton was better. Fred
gkeeton@zbzoom.net wrote: Fred Winterburn wrote: I was going to let someone else jump in on the right plugs. Interesting that you mention not using resistor spark plugs. I used CD ignitions for many years with resistor plugs and only ever had two go bad about 15 years ago. They were Champion RL87YC for an old Volvo. Champion had started going cheap so I switched to NGK and never looked back. The two Champions that basically open circuited were from the same batch and I suspect they would have failed even with the standard ignition. The resistor in the Bosch rotor is definitely a weak link though. Fred

I had some carb issues I was chasing down at the same time I installed my 6AL, and thought I didn't have something hooked up right. When I was going over the setup with one of the MSD Techs, he suggested to run non-resistor plugs. He also suggested not to run the condenser if you were going to use the points to trigger the box. I've talked with people that have used stock Bosch resister rotors, and stock Bosch solid copper core wires with MSD Ignitions, and not had any issues. Then I've spoken to those that had the rotor pop a few miles down the road, and others that have tach's that no longer read the correct rpm. Scott Novak used to post on the samba, and had a wealth of knowledge about ignitions. I tried to create the lowest resistance path for the spark by using 50 ohm/foot wires, non resistor rotors/plugs, and a low turn count coil for lower voltage/max amperage. Although a 009 cap is pretty tiny compared to a V-8/MSD cap, I haven't had any cross firing with plug gaps up to .034. I usually use .032 to give the plug some room to wear.

I remember some back to back dyno tuning with the same engine here on the site. The multiple sparks, and higher energy sparks leaned the engine out slightly from the standard Bosch ignition. In turn the MSD engine was able to be jetted slightly richer, and made slightly more hp. This was on a large engine, and it was minimal, so a small engine may see very little of a change.

Mon Jul 15, 2013 9:01 pm

Hmm, well the duration is hard to compare. You know, with the nature of the inductive it is convenient to measure the total duration of the spark, but really only the first half, or even the first third has enough power to count.

I found the delta to give about 0.2 milliseconds, with that double polarity swing!
Different coils did not change it's action very much, but a low resistance e-core coil did make transfer a bit more power and ran the best too.

supposedly the MDS is 6al about 0.15 milliseconds, single polarity

When testing a high amp coil, one that makes similar current to CDI, I burned out the resistor in the spark plug connector in about 10 minutes flat.
I was driving it at the equivalent of 12,000 rpm tho

Tue Jul 16, 2013 6:14 am

I wouldn't be surprised if the Delta was as short as 200uS, but I would say it's impossible for the MSD to have a duration of 1.5 mS. It defies physics with a 1uF capacitor and a low impedance discharge path. Fred
modok wrote: Hmm, well the duration is hard to compare. You know, with the nature of the inductive it is convenient to measure the total duration of the spark, but really only the first half, or even the first third has enough power to count.

I found the delta to give about .2 milliseconds, with that double polarity swing!
Different coils did not change it's action very much, but a low resistance e-core coil did make transfer a bit more power and ran the best too.

supposedly the MDS is 6al about 1.5 milliseconds, single polarity

When testing a high amp coil, one that makes similar current to CDI, I burned out the resistor in the spark plug connector in about 10 minutes flat.
I was driving it at the equivalent of 12,000 rpm tho

Tue Jul 16, 2013 4:38 pm

oops, forgot the decimal point, it's corrected

Tue Jul 16, 2013 6:54 pm

Now that makes more sense! Fred
modok wrote: oops, forgot the decimal point, it's corrected

Tue Jul 16, 2013 8:13 pm

So to slightly thread highjack here, I have a 2176 that I've run with the MSD 6AL and carbs and am in the process of changing over to EFI, now from what I've read on other forums, EFI users like to utilize resistor plugs to reduce "noise" and prevent issues with the EFI signals but you guys are saying the resistor plugs are no good for use with the CDI package.

What do I do? try each and see what happens?

Tue Jul 16, 2013 8:19 pm

It will work OK with the resistor plugs.