Just want to confirm the settings for this combination, I have one DIS-4 on leading and the other on trailing, with 6 individual Blaster SS coils.

Direct Fire
Constant Duty, 50%
Rising Edge Leading & Trailing

Please advise, thanks in advance

 

FWIW, MSD tech says:

Constant charge, 2.0-2.5ms
Rising Edge
Direct fire

 

How do you have it wired up, cause the rotaries fire more times per cycle and MSD DIS units cant handle it.

I would recommend you sell those DIS and just get LS1 coils, pure and simple.

 

I've already exploded 5 LS2 coils which is why I am using these DIS-4 instead, per the recommendation of people who have gone down this path ahead of me (notably crispeed and David Hayes who couldn't get his 20B working well at all with the LS1's and used this setup instead).

My wiring is as follows, with 1 DIS-4 on Leading and 1 DIS-4 on trailing leading to Blaster SS Coils:

IGN 1/4, 2/5, 3/6 from Haltech harness -> White, Green, Yellow (Trigger Inputs 1-3) on MSD harness

IGN +12v from chassis harness -> Red (IGN 12v) on MSD harness

Brown/Orange (2 wires) from MSD harness (Coil + High Voltage)-> Coils L1/T1, L2/T2, and L3/T3 +ve side

Brown/White, Brown/Green, Brown/Yellow (Coil - channel 1-3) -> Coils L1/T1, L2/T2 and L3/T3 -ve side

 

I had my DIS 4 configured to constant duty and had ignition problems at higher RPMs. I took MSDs advice and switched to constant charge and all problems went away. I have been told that the old analog MSDs like constant duty and the digital ignitions favor constant charge. FWIW i think MSD would know what signal their amplifiers need more than Haltech .

 

Awesome, thanks for this info. Guess I'll find out this weekend

 

Its rumored that new MSD DIS have had a hardware change inside them and that is why they now required a different setting for the spark output mode on the Haltech.

And you say you blew up LS1 coils? how??

LS1 coils are very capable and i have not heard 1 bad comment about them, unless you're shooting for ooodles of power levels, then they can probably not handle it. But how much power are you pushing out of it?

 

I first found the problem when i was zeroing the timing and revved the engine past 6500 to check for variation. When the engine went past 6500 lost trailing spark(DIS4) but the leading kept firing(Digital 6). Instead of revving the **** out of the engine it diagnose it i took an extra CAS and hooked a drill to it. By doing so i also found that i was loosing leading spark above 9000 also. I messed with the duty cycle a little and it helped but did not solve the problem. After pulling my hair out for a while i posted on the MSD forum. They told me to change it to constant charge and ignore what Haltech said. I figured i had nothing to loose since i was able to check it without the engine running. I changed it and it worked flawlessly. I had a good purple spark to at least 13,000 and the spark was much louder when the CAS was spun by hand.

 

I blew up LS2 (not LS1) coils, not sure how, but they were literally melted after some pulls on the dyno. I was also using very low dwell times towards the end, even as low as 3.0ms. We brought 10 coils with us, 2 of which flat out didn't work, and the other 3 we killed.

Here is David Hayes' thread regarding his failure with LS1 coils: https://www.rx7club.com/20b-forum-95/20b-ignition-breakup-issues-656272/

My setup should be good for over 600rwhp, and it's a road race car, so reliable ignition is one of those must have items. crispeed suggested this setup to David and he had great success with it; crispeed also claims over 900rwhp reliably with the twin DIS-4 + Blaster SS setup.

 

It's not the number of firing events that cause a problem.
Besides rotary firing events are no different then piston engines!

The problem would be if he tried to use the same MSD box for a leading and trailing event. The MSD needs at least 60 degrees before it can fire again.

Since he's using one box for the leading coils and the other for the trailing he will have no issues..

 

You got the Crispeed Seal of Approval!!!
You can't go wrong with that... hehe...

 

Well let's hope so! Thanks for the reassurance

 

Yeah, i know that one DIS 4 cant be used on all 4 plugs (in this case on all 6), but i wanna go back the the LS1 issue, the coils the David Hayes thread are those MSD LS1 replacements, arent those supposed to have a "Bypass" plug that voids the igniter just so you CAN use a CDI with them???

The pictures in his thread show both 4 and 2 pin connectors plugged onto the coils, also did they have the correct settings for those coils? They are supposed to be identical to the OEM (black) LS1's but have that bypass option.

Ive had LS1 coils on a 425hp 13B motor with NO problems. Cris, whats the most power you've made with LS1's??

 

Claudio the 425 hp you're talking about would not happen to be Dexter's Miata?
LS coils don't belong on anything import with the word horsepower in the same sentence!
Seriously you got to balance the results and so far they are in the negative side from my findings. The stock FC coils when in good working condition still out perform the LS coils from my experience.
Some well respected tuner's opinions/findings on LS coils.
http://www.efi101.com/forum/viewtopic.php?t=3015

As of late I've been messing around with the M&W stuff. Very very impressed with the results.
No misfire what so ever even at 50 psi of boost at 10500rpm with the plugs gapped at 25 thou.

 

I thought it was 30 degrees.

 

If that don't work then you just switch over to 'constant duty'
The later boxes seem to prefer the 'constant charge' setting though.

 

Cool, thanks. Will have this installed tomorrow and hopefully back on the dyno next week.

 

Well, i can tell you that we've been able to put the LS1 coils in the simulator, and even though its not a real world test, it gave us some insight as to what they are mostly capable off, and we were able to do 16000 rpms with a charge time of 6mS and the coils did not flinch one bit. And we've had reports of people putting them on engines making around 200+ HP per cylinder, of course, anything beyond that is where they start showing signs of missing, but 200+HP per cylinder on a 4 banger is 800hp, to the motor, thats decent power in my book.

 

Could be. Either way not enough for us rotorheads...

 

I'm liking the M&W stuff more and more.

 

Cris, do you have any experience with the Mercury coils that Lance and Brian on EFI101 talk about all the time? Seems like a long duration inductive spark would be of benefit to the rotary if it's strong enough to not get quenched. Are you using the M&W CDI or inductive setup?

 

I'm waiting to see if Lance can satisfy Enzo's need for a stronger spark for his applications.
I have no personal experience with the Merc coils but I've read about applications using them.
I'm using the M&W CDI setup. The debate of cdi vs inductive will always have two sides. The way I see it is that 'inductive' can support 95% of what's out there and there're always the applications that are going to need and benefit from a 'CDI'. The CDI type have proven itself over time mainly due to it's availability but as of late more and more inductive setups have became available and a lot of people are having great success with them.

 

Well I installed it all, but didn't get a whole lot of time to do some testing and we ran into some other problems which we had to take care of before I could test again.

When we tried to start the car though it appeared that the spark was sporadic and somewhat inconsistent...any idea why that might be? I'll have to test some more when everythings back together so it may not be an issue at all, but that appears to be what was going on when we grounded a plug and tested it.

Settings were direct fire, constant charge 2.0ms, rising edge with the following wiring:

IGN 1/4, 2/5, 3/6 from Haltech harness -> White, Green, Yellow (Trigger Inputs 1-3) on MSD harness

IGN +12v from chassis harness -> Red (IGN 12v) on MSD harness

Brown/Orange (2 wires) from MSD harness (Coil + High Voltage)-> Coils L1/T1, L2/T2, and L3/T3 +ve side

Brown/White, Brown/Green, Brown/Yellow (Coil - channel 1-3) -> Coils L1/T1, L2/T2 and L3/T3 -ve side

Big red wire -> starter

Big black wire -> body ground

 

Did you ground the violet wire?

 

Yes sir, both of them...good catch Grounded them both with the main unit grounds.