why not? I'm not saying you're wrong, I just would like to know.


sounds like you're a dick. I'm trying to help somebody not waste money on something that doesn't do what he thinks it does.

and I'm not just bench racing, I have built my 3000gt and tuned it.
two 13T turbos
walbro fuel pump
AEM FPR
450cc injectors
LS6 MAF
MAFT
Apexi SAFC
MSD DIS-4
PMP FMIC
tons of vac reduction
HHH datalogger

that's just a start...... I know what I'm doing.

Because the trailing plug fires too close to the leading plug and there is not enough time to recharge the cap at higher RPMs. If you want to do it with a DIS ignition you need two DIS-2s. I run two Digital-6 and a DIS-2.

Uhhh, where did you get a DIS-6? MSD doesn't even make one?

I apologize, DIS-4, i was thinking 6 cylinder.
if they fire that close, couldn't you just shut off waste spark mode and run them at the same time?
or, go to a "coil on plug setup. the DIS-4 is designed for 4 packs, and can charge them plenty fast enough.

Not to be a dick but i think you should do a little more research before giving advise to someone that you don't know for a fact (against the forum rules BTW). Had the OP listened to you he would have bought a DIS-4 that could not be used by it'self. Injected rotarys do not run two coil packs they run three, two single tower coils that fire the trailing plugs and a dual tower coil pack that fires both leading plugs at the same time. Also IIRC the power FC (that the op is using) can only operate waste spark (factory 3 coil) and will not operate 4 independent direct fire channels. Even if it could A SINGLE DIS-4 CAN'T CHARGE THE CAP FAST ENOUGH FOR HIGH RPM USE.

DIS-4 will run three coil packs, because I use mine with three packs. I said you would have to go to a Coil on plug setup to run a non waste spark "direct fire" . also, you can set the DIS-4's rev limiter to 4k over it's max rpm setting of 9k with the control knobs. If it can fire 8 plugs at 13k rpms, i don't see it having any problem with firing 4 plugs at 8k rpms.

I suggest you go buy one and prove me wrong just don't suggest anyone buy one till you have done so.

That's a 3 rotor using 2ea DIS-4s. Try again.

same concept just more packs, that's why he has two boxes. the point here is it works.

You really don't want to understand / learn how the rotary ignition system works ?

Here is the diagram I made for wiring in the MSD 6AL with the separate 2-step module. The new 6AL-2 has the module built-in, no operational differences. The switch on the clutch pedal wire is to disable the 2-step so when you push in the clutch to start the car the trailing coils still fire.

Attachment 717150

Here is the wiring for the Crane system Tom mentioned earlier, the 6AL-2 install would be identical save the colors of the wires. Someone please correct me if I'm wrong.

Attachment 717151

My point was not to sell him the DIS-4, it was to explain the difference between a "Two-Step" and "Anti-Lag"

http://mazdarx7.iougs.com/ignition.shtml would you consider this a good writeup on the subject?

Let's now explain the difference between an RX-7 forum and a DSM forum.

On an RX-7 Forum, listing what kind of mods you have done to your engine does not earn you rep points. If it did, Allen would be emperor of this forum (since he has torn apart and rebuilt his car at least 3 times :lol:)

Secondly, claiming how great and knowledgeable you are, usually means quite the opposite.

Thirdly, posting an MSD Tech's reply is not factual evidence, period. Plus you didn't understand what his reply meant. He is suggesting running a DIS-4 for all 3 leading coils, meaning they will fire every 120* (since it is a 3-rotor), and another box for the trailing coils, each firing every 120*. When you put a single DIS-4 on a 2-rotor engine, you are asking the box to re-charge in time for 1 chamber to fire the leading and then the trailing, which can be as little as zero degrees of split. If you can't grasp that, then don't give advice on rotary ignition.

And thank you, we understand the difference between two-step and anti-lag, but what the heck is an exhaust valve? :lol: :lol: :lol:

I am not from A DSM forum, that is where the reference was from. and I never asked for "Rep points" I was trying to show that I have hands on experience with the application.

from an MSD tech

Buddy, you're new. You're wrong. And you're arguing with a couple of the most respected members of this forum. They've been doing this for years and know what they're saying. If you want an explanation of why you're wrong, search and read. But please stop dispensing advice until you really have experience with the platform.

God, your car sounds so indepth. You must have spent countless years planning that build!
Sounds like you know EXACTLY what you are doing.


Allen, back off... dont you see his build sheet!


To the OP. Just saw 2 6AL listed up under the "racing parts" section.

https://www.rx7club.com/race-parts-only-228/msd-6al-boxes-966909/

$175 is a bit high for used ones. Might be a good idea just to buy a new one so you know there is no issues with it. They are not that pricey.

Me a dick? Nah.

lmao... owned?

btw not trying to thread jack but i got 2 DIS-4 HO boxes if anyone needs them.

Are you guys sure you're arguing about the same thing for the ignition boxes? dpartinvr4, so far you've quoted two sources that mention using multiple boxes for a rotary engine. They both specifically said that there was a box for leading and another box for trailing. So are you arguing that you can run both leading and trailing on one box or just that you can use a single box for leading and a single box for trailing? It sounds like you're claiming one thing from your earlier post but you keep proving something else.

Now my actual question, would it be safe to keep the HKS twin power and just run a single MSD box on the leading to gain the 2-step ability? I understand I would still have to cut off the trailing but I'm just wondering if it might be two much to actually run them both together.

I can assure you that is just the Tip of the iceberg. but i forgot, we use youtube as proof here

what DP quoted the last time is correct, you can use a MSD 6A or Digital 6 or similar for the wasted spark, leading coils. He was originally recommending a DIS-4 box for leading and trailing, which does not work period. If you want to do sequential leading ignition (if your ECU is capable of it, I don't think the PFC is..) then you need two same boxes for each leading, or one DIS-2 for the leading, you can also use a DIS-2 for the trailing.

For your question, no I don't think you would want to combine the HKS twin power on top of a CDI ignition, unless you could disable the leading and just run the twin power on the trailing properly. Trailing spark isn't as important, I would rather have a CDI on my leading than a twin power on both, and you can always add some kind of spark amp to your trailing. On that note, I have two Digital 6+ boxes I need to get rid of (along with a DIS-2 and some brand new HVC-II coils) I'll give you a good price, PM me. :D

It sounds like you should just fuck off, not like we asked you to come to this forum with your indispensable advice.