MSD Ignition
 

I happen to be messing around with my ignition and just happen to notice how many people here have soo many different views on MSD's. Well I was reading and noticing different setups and figured I try something that I didn't see anyone doing. I had 2 MSD 6AL's already in my car running through the cap 1 6al for leading and one for trailing in an RX3 13B large streetport with 600cfm holley carb and lot's of fuel going through it. Motor ran great with this setup and I thought what the hell try direct fire. So I wired it up that each 6AL would fire one coil each and kept the trailing wired like factory through the cap and moved the trailing wires to the leading position as per Jeff20b. From what I can tell just from idle and response it works great and seems that the throttle response was very noticeably better than running the msd's through the cap. I haven't had a chance to drive the car seeing that it needs the driveshaft cut and the exhaust put in, open headers right now, I love the noise but I'm pretty sure my neighbors hate me especially when I keep the car running for 20 minutes while I tune it. One thing I noticed is that there wasn't a major difference when I unhooked the trailing and just ran on the leading plugs and when the trailing was plugged back in idle seemed to change slightly. Just one question is do I need another another 6AL to take advantage of the rev limiter. The rev limiter does work because I did peg it with the trailing off and I was to scared to try to hit the rev limiter with the trailing hooked on thinking that I'd get a ping at the top because the leadings would be hitting the rev limiter and the trailings don't have a rev limiter. This is just some of my findings from messing around with my car and also the leading plugs really looked good. Hell they should they have one 6AL each. Just like to hear some input.

Im having sort of the same question
 

Yesterday, My friend gave me a fb distributor with stock coils..
Im thinking of eather replacing my stock t2 igningtion on my 88t2 to the
distributor ignition.

Right now im running a digital MSD 6 plus on the leading coil, and i also have a MSD 6a which is not currently on because i had not gone with the distributor setup.

since you are already running some were around where i want to be,
can you please give me an idea on how to set it up.

should i use my fc ignition coils or replace them with the fb coils?
should i make it directfire? or should i not?

also.. can you tell explaing to me how to do change the stock t2 distributor to the fb? or give me a site where this mod has been done.. ect.. ect..

Thanks so much.

The T2 doesn't have a distributor and is superior to 1st gen ignition components. You'll need to do a lot more researching before spending any money. There is a very real chance you'll reduce power levels if you start hacking things without knowing what you're doing.

13btnos, you could wire up a switch to turn trailing off so when you know you'll be doing some spirited driving, you won't accidentally over rev your engine. Of course this doesn't cover spur-of-the-moment type things if you forget to flip the switch. On an NA, trailing doesn't do much for power. I didn't notice a difference at all since my leading was powerful enough to fully take over trailing's job. Another guy who chassis dynoed his engine didn't see a difference. If there was a difference, it was within the margin of error for the dyno (about 2HP). You can get another 6AL if you want to, but it is sort of an expensive route to take just for the negligeable amount of power the trailing circuit add to your engine's overall power output. It's not like you have emissions to worry about. what you need is some sort of RPM activated switch to cut trailing when the two 6ALs are cutting leading.

Maybe you could get an aftermarket shift light and instead of shining a light in your face, you could connect it to a circuit that would kill the power to your trailing ignitor. If you get an MSD brand light, it'd be less expensive than a whole 'nother MSD 6AL, and it can use the same resistor- uh RPM pills. Yeah, one of those relays that goes to one circuit when off, and then goes to another when energised... I could build something like that... seems easy enough.

Yeah thanks for the reply jeff20b that's exactly what I did was put the trailing on a switch. The two 6al's on the leading man I couldn't believe the difference and with the direct fire the motor just sounds soo much better and the response alot more crisp. I found no real difference in how the motor reacted with the trailing disabled the only reason I have the trailing wired up is to keep the plugs clean that's about it. The rev cut idea for the trailing was something I was thinking of to but I like the switch better. It's cheaper. LOL... Thanks again for the input.

Direct fire being... one 6A and one coil for each leading plug?

-=Russ=-

Yes that's correct.

That sounds like the experience I had the first time I experimented with direct fire on my REPU several years ago. The exhaust note actually changes and throttle response does indeed become more crisp etc. I suspect the exhaust note changes because that late firing leading spark, which occurs 180° after the initial leading spark, is burning more fuel and results in a smoother tone. A little later I got to hear some 2nd gen RX-7s and recognised the sound as being the same since they also have a direct fire leading ignition system which fires both plugs at the same time.

I have 2 MSD 6ALs running on my FB. One runs leading through a second gen coil in direct fire mode. The other runs trailing through the cap. The car runs great and from what we saw on the Dyno it lost about 10 HP with the trailing not working. All of my plugs stay spotless.
BTW we run the same carburator.

My theory is that if leading is powerful enough (on an NA), the loss of trailing is not noticed. The power output of the engine in my REPU was lower than it should have been due to a clogged exhaust and lots of missing chrome on the rotor housings. I'd say it was below 100HP. I think I'd feel the loss of 10HP on my butt dyno. Tnat's 10% of the engine's total power output! Instead, I felt nothing when switching trailing on and off while accelerating up a steep hill. If it was a loss of only about 2HP or less, as I suspected at the time, I'd be less able to feel it.

I'll do some dyno runs some day. I no longer have the clogged exhaust to test with, but that's a good thing. :)

Yeah I have the trailing hooked up through the cap I was thinking of adding another 6al for the trailing but I'm trying to sell this damn rx3 so I can finish my datsun 1200 up but no one has shown any real interest in it. I've had a couple people come look at it but nothing and I have a friend in Florida looking for people to buy it but it's another thing when I have to ship it because I'm in San Diego, CA. Right now I've got 2 6al's, one for each coil for the leading, I had them and just wanted to try it out and it works great. You have that 6port bridgeport don't you? Yeah I'm a Holley guy everyone in SoCal use Weber style carbs I just love Holley carbs that's all I know. I've used webers before but nothing like a well tuned rotary with a holley 4 barrell especially if your running NOS you can't beat a holley. I'll probably get flamed for that comment.LOL...

ARMYOFONE
"I have 2 MSD 6ALs running on my FB. One runs leading through a second gen coil in direct fire mode. The other runs trailing through the cap. The car runs great and from what we saw on the Dyno it lost about 10 HP with the trailing not working. All of my plugs stay spotless.
BTW we run the same carburator."

so.. should i run my fc with direct fire on leading coils with a Dital MSD 6 plus on; and a regular MSD 6a for both my trailing with the cap my t2 or not?

13btNos:

The site you sent me to is very helpfull, but its kind of hard to understand.

There is a guys around were I live that runs a Rx4 with the ignition setup im striving for.
He tells me little things here and there, but Never the complete package.

I dont know why people are so greedy when it comes to rotary engines knowledge.
(not you guys)

You got it :bigthumb:

[QUOTE=13btnos]


"I have 2 MSD 6ALs running on my FB. One runs leading through a second gen coil in direct fire mode. The other runs trailing through the cap. The car runs great and from what we saw on the Dyno it lost about 10 HP with the trailing not working. All of my plugs stay spotless.[QUOTE]


since you have access to a DYNO, can you check which one is better for direct fire? FC leading coil VS MSD blaster/stock coils.

I have been using direct fire for years and have experiemented with different set up such as FC, stock and MSD. I noticed that even with the el-cheapo direct fire, DLIDFS, the spark on a blaster/stock coil is cleaner than the FC coil. Also, using a timing gun, the light is much more intense on a blaster coil; whereas, on a FC coil, you will see spark going on and off. its like a morse code.

thanks

whoa. 4 6a's!! damn that is an expense igntion setup for direct fire.

[QUOTE=wackyracer][QUOTE=13btnos]


"I have 2 MSD 6ALs running on my FB. One runs leading through a second gen coil in direct fire mode. The other runs trailing through the cap. The car runs great and from what we saw on the Dyno it lost about 10 HP with the trailing not working. All of my plugs stay spotless.Sorry but that quote wasn't me it was Armyofone who has that setup.

You think 6A's are expensive try 2 MSD DIS-4 HO at $418 each and the 4 coils at $48 each that I'm running on my turbo project now that's expensive. I get a break on 6AL's from a friend there's no way I'd pay for the full price on those. It's funny people don't want to dish out money where it counts. It takes money to make serious power out of these engines and takes even more to make it reliable power.

yeah, thats nuts. but you do what you have to. i have no problem paying for it....when i can. but i reserve my right to bitch about it.

my bad. I should slow down. coffee day and night here.

Yeah I bitch about it also but at the end of it all I pay for it because I have too. It does suck but that's the price you pay for the things you love to build and drive. I'm 10g's into my project and still not close.

Oh and to add on I run a MSD Blaster for trailing. I have not noticed a big difference between the FC and the Blaster signature. What I do know is that the spark stays perfect all the way up to 11,000 RPMs without breaking up.