proz07

iTrader: (6)

so iv beed surfing the forums and iv seen some ignition setups w/ 3 msd 6a's or similar. now y would you do that instaed of using say the dis-4 msd ignition box?
the reason i ask is the 6a is a single coil amp corect then y use 3 of them instead of one dis-4.
and the way i understand it the msd boxs are the same as say the hks twin power in what there purpose is which is to provide enough voltage to jump the plug gap during high pressure/rpm applications? correct me if im wrong
thanks
z

diabolical1

iTrader: (3)

not sure what the features of the DIS-4 are, but unless it's capable of handling two separate signals, you'd need at least two of them, just like any other ignition amplifier. rotaries have 2 separate ignition systems and you'd need at least 2 of any amplifier if you want to amplify both.

for 2 rotor engines:
you can run 1 box on the leading (which i did a long while back) = 1 box
or ...
you can run 1 box leading and 1 box trailing = 2 boxes
or ...
you can run 2 boxes on the leading (rotor 1 and rotor 2) = 2 boxes
or ...
you can run 2 boxes on the leading (rotor 1 & rotor 2) and 1 trailing = 3 boxes

proz07

iTrader: (6)

well the dis-4 can run up to 4 coil packs and being that a 2 rotor only runs 3 (1 waste fire leading, and 2 seperate trailing) correct me if im wrong on the waste fire.
so i dont see y you would run 2 muchless 3 when you can get one box to run it all plus some?
in any case after posting this i found more info i was looking for 'isnt that always the way'.
but i am running the aem universal ems 30-1900 and will be running either 4 msd 8207 coils or the aem coil packs if i can find any info on them they seem to be pretty new yet. from what iv read this setup should be good for 600rwhp i want 450 to start and then go from there.
anyway later
z

diabolical1

iTrader: (3)

what year car?

at any rate, my understanding is painfully limited and elementary, so what i'd do is PM the user Jeff20B. he's very well-versed in ignition systems. he should be able to answer your questions.

RETed

You can't do that.
If you did a proper search, you would've found the correct answer.
The DIS-4 just cannot fire what you want on a rotary ignition firing trailing split.


-Ted

proz07

iTrader: (6)

i will take a look but care to elaborate RETed

z

RETed

It doesn't work.
Period.
The DIS-4 need sequentual, evenly spaced ignition events to work.
If it doesn't see this, it'll barf.
The FC and FD ignition events are not evenly-spaced.
Trust me.
We tried on an FD, and it didn't work for crap.

It's not a "dumb" CDI box.
If you want something like that, you'd need to step up to an Autronic or MoTeC unit, which is BIG BUCKS!


-Ted

proz07

iTrader: (6)

well then theres my answer, too bad there was no research support as to y it didnt work.
thanks anyway

z

2a+RoN

the dis-4 doesn't work because it only has one capacitor and it cannot recharge fast enough to fire the leading and then the trailing right after that. The expensive units like the motec/autronic have two capacitors so that they can both have plenty of time to recharge before firing the next event. The AEM also has this, but its a piece of **** so don't waste your time with it.. Ask me why i know....

Theoretically, you could run two dis-2 boxes or any other two channel box, one for leading and one for trailing, as there would be plenty of time for the capacitors to recharge as the events would be 180* apart.

proz07

iTrader: (6)

now thats more of an answer i was looking for thanks 2a
anyway did you use the aem's latest cdi/twin fire or the older versions?

im also interested in aem's cdi coilpacks but iv yet to find anyone whos used them. ill also be talking with my aem shop on this but just looking for some pre-info.

thanks for an inteligent answer
z

RETed

Just did a search on "DIS-4"...

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/some-input-msd-dis-ignitions-387369/
https://www.rx7club.com/single-turbo-rx-7s-23/msd-boxs-327097/
https://www.rx7club.com/general-rotary-tech-support-11/msd-ignition-setup-223879/

That didn't take that long to find...


-Ted

Marcel Burkett

I have experienced what ted and Ron is saying , I even have a friend who tried 4 6A boxes with 4 blaster ss coils and found that it couldnt keep up over 30 psi . He was advised to use two Dis 2 boxes , but I used a Dis 2 on my trailing ignition and the spark was very poor. He has since gone with M&W and I with the R500 and neither of us have had any problems .

EvilJester

I was watching Directfreaks vid http://youtube.com/watch?v=dXu9Txu_WOg, on his set up. Sorry guys but i dont know that much about it, but you say it cant be done but he did it. Are we talking about the same thing?

three MSD 6 als
custom MSD coil set up

2a+RoN

I used the latest twin fire cdi. Blew within 3-4 hrs on the car... Seemed to be doing fine, just started driving it around, then it wouldn't start and found that the box kept blowing fuses.. I was going to go with the 500R but I have gotten effed over by the last two people I have bought one from (1 a dealer and the other a forum member) so I will be going with the motec/m&w unit now..

2a+RoN

Yes you could use 3 msd 6a's if you wanted. I'm running direct fire 4-coil so I would have to run 4 boxes. I'd rather save space and weight and run a box I can trust.

EvilJester

Lets pretend that i am stupid..........accually we dont have to pretend, i am stupid.

What exactly do you meen?

proz07

iTrader: (6)

he means the 6a has one signal input and output so it will only run one coil so you would need 3 6a boxes to run a stock rx7 ignition or in his case running 4 because he went with aftermarket coils 4 of them; 1 per plug.


in any case im goin to look into the m&w cdi alittle more thanks

z

Marcel Burkett

U can run 4 boxes on the stock 3 channel ignition system if u use two on the leading and one on each of the trailing ! , I used to run two 6A boxes on two separate leading coils and none on the trail using the stock series 6 ignitor (we have also found that the spark is VERY POOR without the boost of the ignitor ) , all u have to do is use the same single leading trigger output from the ignitor to fire both boxes , ie run both boxes parallel , u will still be running wasted spark and everything . I dont know exactly what it is but u will see some guys running the MSD stuff and making big power and some (like myself ) cant even past 15psi of boost , my racer friend deals directly mith Mr Lopez from Lopez racing , Mr Lopez uses two DIS2 boxes and MSD coils and makes over 650RWHP @ 30 psi , he said that at the upper rpm and boost levels tuning is extremly critical , the a/f ratios need to be leaned out or there will be break up ! , my friend tried this and he just wasnt making the power , he still had break up ! . I prefer to go with something that has a 100% proven record , like the R500 or the M&W , instead of wasting time and money with the cheaper stuff.

PDF

When using a distributor ignition can the MSD 6A be fired by the factory ignitor or will it only work with the magnetic pickup?

Marcel Burkett

The Msd 6A is connected to the coil , it can be used with a points type distributor , electronic type with a magnetic pickup or even as an ignitor , check out their instructions , http://www.msdignition.com/pdf/6%20series/6series.pdf

enzo250

The reason a dis-4 doesn't work is that it requires at least 60 degrees seperate between channels. Obvisouly a no-no with rotary's...

Twin cap's allow the cdi to fire two channels together if need be... or any degree seperation..

IAN

iTrader: (3)

Cool. The M&W has one specific for the rotary.

And only one box?

Will this work with methanol/water injection?

But of course no canadian distributers or many usa ones.

Marcel Burkett

The M&W is similar to the R500 in spec , only thing that the R500 has over it is that it can be switched to a high voltage output setting if required (yes its a switchable dual output box ) , the R500 dealers say that it will burn almost anything you can throw at it so I guess the M&W will perform the same way . My tune is very rich right now and I also run WI , my exhaust temps are about 1050deg F and there is no breakup or hesitation at all . just the other day I forgot that I had both leading coils disconnected and cranked over the motor ......., guess what , it started right up on the trailing plugs alone !

IAN

iTrader: (3)

Can you use your stock coils?

Thanks for showing me the autronic CDI. Which would be best for street/track use? And some methanol/water injection.

I like the 500R selection of 2 outputs. You can use one for the street and one for the track I guess.

Ian

ronbros3

I use two Crane DIS 2 boxes, and 4 Crane LX-92 coils, 10mm wire,and 4- 10.5 NGKs. Microtech LTX8 ,setup 4 yrs ago. No more ignition problems. Ron