Hyper4mance2k

iTrader: (40)

So my MSD 6A is controling my leading plugs. no leading ignitor. you know what I'm talking about. Anyway, when setting my timing the other day i noticed that there is a missfire on off both of my coils now i know with the msd there's wasted spark and all that, but every second or so it seems there's just not enough juice to make the next spark causing an annoying stumble. I'm runing stock coils so could this be the problem. I plan on upgrading to the new coil MSD has out. The Blaster HVC II designed for race/street apps with the 6a. Some specks on it are as follows.
Primary resistance: 0.16 Ohms
Seconday resistance: 630 ohms
max volts: 44,000 V
Inductance: 3.5MH
Turns: 100:1
Peak currant: 450mA
spark: 450 us

The MSD 6a performes as such
Operating Voltage: +10-18 VDC Negative Ground
Current Requirements: 5 Amps-5,000 RPM, 10 Amps-10,000 RPM
RPM Range: 15,000 RPM with 14.4 Volts
Spark Duration: 20° Crankshaft Rotation
Energy Output Max: 105-115 mJ Per Spark
Weight and Size: 2.75 lbs, 8"Lx3.5"Wx2.25"H
Voltage Output Max: Primary: 460-480 Volts, Secondary: 45,000 Volts (w/ Blaster Coil)

Now this seems to be the best coil for my set up. I'll have 3
Here is my question. Should the two leading coils be wired in a series or in parallel. This was a debate a while back and no real answer was ever reached. I have had the stock coils wired both ways and noticed no difference. I was wondering from the technical brains what the best answer is.

Rx7carl

I had mine in parallel if that helps. Same setup.

DBOGGSRX7

Your coils should be wired in parallel. if you wire them in series, each one only get half the voltage supplied by the circuit. ie 6.25 volts instead of 12.5v. wiring them and parallel gives them both full voltage, but double the amount of load on the circuit, ie if each your coils have 100 ohms of resistance, and you wire them both in parallel, you now have 50 ohms of resistance.

dennis

Jeff20B

iTrader: (13)

I tried the whole MSD on a rotary with two (stock) coils experiement once and was not impressed. It's been collecting dust since '01. I picked up a 2nd gen leading coil last year for my MSD and all I need now is a test vehicle (my REPU test vehicle is between exhaust sytems and carburetors, plus it needs a set of tires and the rebuilt engine needs to be broken in).

You should not hook an MSD to two coils. You can think of it like this. The MSD's output is not infinite. In other words, it has its limits. You're converting 12 volts to around 400 volts and force-feeding the coils which causes them to act like step-up transformers instead of what they were designed for, which is an inductive kettering type of a spark. Your coils are probably on their way out. What's more, that 400 volts has less amperage than the original 12V, and hooking it to two coils in parallel reduces the amperage by 50%. This translates to a colder spark in the end (it's basically the same voltage as a single coil, so it can jump the same distance, but it will be cooler and won't ignite as much fuel).

The only solution that I can see, for our engines, is to use a dual output coil like a GM DIS or a stock 2nd gen leading coil. This type of coil has one primary and two secondary sets of windings. Even though the secondaries share the primary, the primary winding can be driven more fully and effectively by the MSD than two seperate coils ever could. Another plus is these dual output coils are of the E-core type. They're a much more modern design and are alot more effecient.

So now you are faced with a choice. You can either replace both your antiquated coils with more of the same, or you can make a change to something that I believe is a better choice. Others have gone with a DIS coil on their MSDs and have never fielded any complaints about it. I'm willing to dust off my MSD and give it a 2nd chance (yes, even the DLIDFIS guy is willing to give his MSD a chance now that he has a 2nd gen coil at his disposal). I'm Jeff20B, and I approve this mes- *cough* sorry.

Hyper4mance2k

iTrader: (40)

hmmm sounds like a verrrry good opinion. That is exactly the type of response i was hoping for. Do you know of any aftermarket coils like that?

Jeff20B

iTrader: (13)

Yes. Here's one that RX-Midget uses with his MSD in his 13B powered Midget. http://www.jegs.com/cgi-bin/ncommerc...89&prmenbr=361

Hyper4mance2k

iTrader: (40)

cool i found msd makes one, bot its only 40,000 volts as opposed to the accel's 45,000. Will 5,000 volts make that much of a difference?

Primary Resistance: 0.35 ohms
Secondary Resistance: 7.8K ohms
Maximum Voltage: 40,000 volts
Inductance: 4.2 mH
Turns Ratio: 80:1

Jeff20B

iTrader: (13)

I highly doubt it as voltage only rises when resistance goes up. In other words, if you have a dirty plug or a large gap, the voltage will go up and the duration will go down. Then again, this holds true for kettering, but I'm not sure about CDI in this case. Either way, that coil is emblazened with an MSD sticker, so it should logically be made with the MSD's CD spark in mind. Of course just because a company is known for its CD boxes dosn't necessarily mean its coils are golden too.

What I'd like to know is if anybody here has ever done an experiment with both these DIS coils on their MSD powered rotary. Failing that, you might as well go with what you personally like the best. You know, whatever will look best under your hood. Personal preference will probably win over 5k of supposed volts... probably. Anybody?

Hyper4mance2k

iTrader: (40)

good response. LOL. Thats exactly what i was thinking. LOL. I can't find any more info anywhere on the accel coil other than it produces more voltage. So i'd assume that means it would probably have a higher resiance than the msd, right? And in theory a higher resistance causes a hotter, but shorter duration spark. Where as the lower the resistancethe longer the spark duration, but smaller spark?

Jeff20B

iTrader: (13)

Dielectric strength, number of turns, inductance flux, meh. Go with whatever you like the best. If it were me, I'd probably go with the Accel because RX-Midget uses it, and I also have a 13B powered Midget, and the happiest color is yellow, and I can easily find it on the Jeg's website.

LOL, you're going to have to wait for someone else to come into this thread and give his opinion because I'm not qualified enough to give you a solid answer.

CarlRx7

ill buy the msd dual output dis coil if some1 can tell me if the 10mm magncore wire will fit it. connector looks like the opposite of wut the msd blaster 2 coils used.

carl.

chuck8313BTSDS

Hyper
Call MSD's 800 number and talk to a tech. I called 3 days ago to make sure there series 6 boxes will work on a rotary. His reply was yes and that the series 6 boxes will even run two coils for the leading side.
chuck

Hyper4mance2k

iTrader: (40)

well my msd coil is on the way I'lllet you guys know how it all works out. if it sucks be sure you all will here about it!! it ships on monday and will be here in 2-4 days so we'll see...

SS124A

I agree,
this is the set-up I am using in the RX-3. I should take some pictures to show you.

I mounted an FC trailing coil on top of the leading coil and used 4 80mm bolts to hold it all together. Works very well.

BTW, Jeff, if you still have that MSD on the shelf collecting dust, what say you sell it to me to experiment with... I am working on a rev-limiter that will work with the direct fire we are all playing with.

cpa7man

iTrader: (2)

Is this basically what you guys are talking about, but just replacing the regular coils with the DIS coil. How many DIS coils would you need?

http://www.mazspeed.com/msd.htm

Hyper4mance2k

iTrader: (40)

Yes, and Yes take some pictures

Jeff20B

iTrader: (13)

Carl, Magnacore has some good thinkers working for them resulting in a great product with some decent science behind it. I would guess that if the 10mm wires use a standard (whatever standard is) connector and boot, they ought to fit. I know my set of stock 1st gen NGK wires fit a 2nd gen leading coil.

chuck8313BTSDS, MSD recieves so many phonecalls asking if their products work on rotaries. The Paul Yaw and Mazdaspeed info may have something to do with the answer you got. It doesn't mean it's the most ideal setup though.

Hyper4mance2k, be sure to let us know how difficult/easy it was to wire up and if you can notice any improvement.

waapst, ever since getting ahold of a 2nd gen leading coil, I've decided to keep my MSD. Hey, could you take some pics? I'd like to see how you stacked the coils. I have one FC trailing coil kicking around that I could mount with the leading coil, and I'd like to get some ideas from your setup, if I could.

cpa7man, that's exactly what we're talking about. We're essentially updating the old information on that article with new info. You'd only need one because the trailing ignition circuit is left totally stock other than moving it to the leading part of the cap (to take advantage of the carbon button and only one gap to jump).

70ghiavert

I have been researching the direct fire ignition and has gotten different opinions. I am new to the rotary world. I am installing a 13b street ported with a supercharger in my car. After reading about it on these post and other sites I was ready to buy the msd and do a set-up like the one shown on the mazdaspeed website. However, when I called Atkins I was told that the ignition I have (84-85) is very good and it will not make much difference. What have you guys experienced? Any real gain in hp or other advantages?

Thanks,

Edwin

Hyper4mance2k

iTrader: (40)

starts about 1000000 x 5647344% better. emissions are way better, improved gas mileage. as far as performance little to no gains. A msd unit will help to flatten out the torque curve alot. below 3000 rpm it is multipule spark so it helps alot..
my wireing is getting pretty messy under the hood so when i put this in, I'm going to move my msd and clean things up alot thinking of moving my battery to the passenger storeage bin and putting the MSD and Coils where the battery is now.

SS124A

When you pick up your MSD box be sure to spend the extra cash for their BTM model.

this one has an on-board boost sensor which will retard timing. it also has the rev limiter like the 6AL.

I have an old school version that I have been experimenting with. I am trying to fool the circuit into thinking there is boost when i have my NO2 activated... This Box also allows input from either

My current set up uses an FC emmissions solenoid between my carb vaccum source and vaccum advance bulbs on the dizzy. when i flip a switch it closes the vaccum source to the dizzy so it will run where ever i set the timing.

As you can see there are problems with this... with the NO2 off, it has really retarded timing that advances a bit but still not where it should be.

SS124A

When you pick up your MSD box be sure to spend the extra cash for their BTM model.

this one has an on-board boost sensor which will retard timing. it also has the rev limiter like the 6AL.

I have an old school version that I have been experimenting with. I am trying to fool the circuit into thinking there is boost when i have my NO2 activated... This Box also allows input from either

My current set up uses an FC emmissions solenoid between my carb vaccum source and vaccum advance bulbs on the dizzy. when i flip a switch it closes the vaccum source to the dizzy so it will run where ever i set the timing.

As you can see there are problems with this... with the NO2 off, it has really retarded timing that advances a bit but still not where it should be.

Hyper4mance2k

iTrader: (40)

se i made the mistake years ago and didn't want to spend the extra money and i bought the 6a.... funny thingit has been in all 3 of my civics in my supra, in my jetta, and in both my Rx-7's i got this thing in 1999 and she's still workin. i think...

rotarygod

iTrader: (1)

I don't think I'd feel good running a timing retard on only the leading ignition since that is what will happen with this box when the retard kicks in.

Hyper4mance2k

iTrader: (40)

hey good point that didn't even cross my mind...

mikey D

if its good enough for paul yaw its good enough for my car.