!!will my msd ignition box and or coil work on my rx7 first gen!!
02-13-05, 05:12 PM
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!!will my msd ignition box and or coil work on my rx7 first gen!!
I have an msd 6a part #6200 multiple spark discharge box and a coil these are out of my friends 97 integra gsr was wondering if the box could be hooked up in mine?
02-13-05, 08:54 PM
#4
Absolute Power is Awesome
This is a really excellent article.
http://www.smbaker.com/rail/msd6a.html
You only need one MSD on the leading, if you wanted to do trailing too, you'd need three.
http://www.smbaker.com/rail/msd6a.html
You only need one MSD on the leading, if you wanted to do trailing too, you'd need three.
02-14-05, 05:33 AM
#6
Oh man, I wonder if anyone here has ever had shoddy performance from an MSD and two stock coils? I sure did. How about two blaster coils? I forget which type of MSD brand coils can only be mounted vertically. Are they the type he recommended? I hope not.
If you're going to use an MSD on a rotary, in my opinion, it's best to use a double ended or 'DIS' coil, such as a 2nd gen leading coil for cheap, or an MSD or Accel brand if you don't mind paying a little extra. The single primary coil inside is much better suited to the high voltage, low amperage CD output of the MSD than two seperate coils.
I still have an MSD 6AL and and picked up a 2nd gen leading coil. They'll both go on my next rotary project that requires rev limiting, along with a switch to turn trailing off so I don't pull a peejay (he over-reved on trailing alone and blew some apex seals).
It's too bad that the author of that web page doesn't seem to understand a few basic things. For instance, he suggests cutting though the back of a dead ignitor instead of simply prying the back off (prying the back off requires tons less work, and easier cleanup of the clear goo). He also wires it up backwards, but at least mentions that they're criss-crossed, and to check the connections with a continuity tester. Anyway, he puts together a nicely written article with clear, colorful pictures and yet for all his work, he neglects the simplest and easiest mod of all time when going direct fire; moving the trailing wires over to the leading part of the cap! For shame.
LOL of course I'm kidding, but if he could overlook such an important and easy step as the cap position swap for the trailing wires (we are trying to upgrade over stock, aren't we?), then maybe his other information isn't quite up to snuff either? For one thing, while there was a brief comparison between kettering and capacitive discharge ignition systems on his page, he failed to point out that a rotary's long combustion chamber and the extremely short spark duration of a CDI box tend to not go too well together when the multiple sparks decrease to one at higher RPM. Infact at 3k, or was it 6k? Anyway, when the MSD switches to just one spark, it's often less effective than a stock J-109 (or at least it was in my case where DLIDFIS actually worked better) where the short duration spark simply doesn't have enough time to ignite very much fuel. Compare this with the J-109's longer duration, lower voltage spark. The actual voltage seen at the spark gap is only as much as is necessary to jump the gap within the confines of local pressure and temperature, level of ionization etc near the plug. The rest of spark the energy is dissipated as spark duration.
By the way, a J-109 can output some pretty decent sparks at high RPM if given the chance. We're talking 10k RPM at two sparks per rev (as in a stock setup), if I remember correctly, or 20k with single sparks (if you're into that sort of thing). Yes, the J-109 is no slouch. It's even better if you can have direct control over the dwell duty cycles to the point where the ignitor is on the verge of entering current-limit mode without going over, and it will stay cool while providing a very juicy spark. Although there is no way to control dwell directly when the ignitor is installed on a distributor, the VR signal it recieves from the reluctor spinning nearby is referenced and the dwell is set automatically (and appears to be perfectly adequate for NA and even boosted use up to 400HP at least... so much for all those doubters out there, huh?). If however you have a programmable ignition controller, you can set the dwell duty cycle so each ignitor draws up to about 5 amps during charging. HEI ignitors can handle up to 6 amps. It's great fun playing with long, fat sparks on the bench while knowing why my engine is so happy using the same components. You guys should get into bench testing some time (I place no warranty on anything you just read, so it's on your shoulders if your ignitors or coils get damaged while following my advice and/or suggestions
).
Oh, and you're not better off with an MSD or two on trailing at less than 400HP because it costs too much for the performance it provides (RETed recommended CDI on high output boosted engines). Besides, if you had 400HP on tap out of your rotary, I doubt you'd be hanging out in the 1st gen section trying to learn about ignition systems. Sorry if this post doesn't make sense or sounds rude; I've been awake for a while.
If you're going to use an MSD on a rotary, in my opinion, it's best to use a double ended or 'DIS' coil, such as a 2nd gen leading coil for cheap, or an MSD or Accel brand if you don't mind paying a little extra. The single primary coil inside is much better suited to the high voltage, low amperage CD output of the MSD than two seperate coils.
I still have an MSD 6AL and and picked up a 2nd gen leading coil. They'll both go on my next rotary project that requires rev limiting, along with a switch to turn trailing off so I don't pull a peejay (he over-reved on trailing alone and blew some apex seals).
It's too bad that the author of that web page doesn't seem to understand a few basic things. For instance, he suggests cutting though the back of a dead ignitor instead of simply prying the back off (prying the back off requires tons less work, and easier cleanup of the clear goo). He also wires it up backwards, but at least mentions that they're criss-crossed, and to check the connections with a continuity tester. Anyway, he puts together a nicely written article with clear, colorful pictures and yet for all his work, he neglects the simplest and easiest mod of all time when going direct fire; moving the trailing wires over to the leading part of the cap! For shame.
LOL of course I'm kidding, but if he could overlook such an important and easy step as the cap position swap for the trailing wires (we are trying to upgrade over stock, aren't we?), then maybe his other information isn't quite up to snuff either? For one thing, while there was a brief comparison between kettering and capacitive discharge ignition systems on his page, he failed to point out that a rotary's long combustion chamber and the extremely short spark duration of a CDI box tend to not go too well together when the multiple sparks decrease to one at higher RPM. Infact at 3k, or was it 6k? Anyway, when the MSD switches to just one spark, it's often less effective than a stock J-109 (or at least it was in my case where DLIDFIS actually worked better) where the short duration spark simply doesn't have enough time to ignite very much fuel. Compare this with the J-109's longer duration, lower voltage spark. The actual voltage seen at the spark gap is only as much as is necessary to jump the gap within the confines of local pressure and temperature, level of ionization etc near the plug. The rest of spark the energy is dissipated as spark duration.
By the way, a J-109 can output some pretty decent sparks at high RPM if given the chance. We're talking 10k RPM at two sparks per rev (as in a stock setup), if I remember correctly, or 20k with single sparks (if you're into that sort of thing). Yes, the J-109 is no slouch. It's even better if you can have direct control over the dwell duty cycles to the point where the ignitor is on the verge of entering current-limit mode without going over, and it will stay cool while providing a very juicy spark. Although there is no way to control dwell directly when the ignitor is installed on a distributor, the VR signal it recieves from the reluctor spinning nearby is referenced and the dwell is set automatically (and appears to be perfectly adequate for NA and even boosted use up to 400HP at least... so much for all those doubters out there, huh?). If however you have a programmable ignition controller, you can set the dwell duty cycle so each ignitor draws up to about 5 amps during charging. HEI ignitors can handle up to 6 amps. It's great fun playing with long, fat sparks on the bench while knowing why my engine is so happy using the same components. You guys should get into bench testing some time (I place no warranty on anything you just read, so it's on your shoulders if your ignitors or coils get damaged while following my advice and/or suggestions
).Oh, and you're not better off with an MSD or two on trailing at less than 400HP because it costs too much for the performance it provides (RETed recommended CDI on high output boosted engines). Besides, if you had 400HP on tap out of your rotary, I doubt you'd be hanging out in the 1st gen section trying to learn about ignition systems.
Sorry if this post doesn't make sense or sounds rude; I've been awake for a while.
Last edited by Jeff20B; 02-14-05 at 05:49 AM.
02-15-05, 09:41 AM
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http://www.geocities.com/cd23c/dlidfis.html
do yourself a favor and read Jeff's write up and how to. I did and it's AMAZING how well this works on my gsl-se)
do yourself a favor and read Jeff's write up and how to. I did and it's AMAZING how well this works on my gsl-se
)
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02-18-05, 09:01 PM
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02-18-05, 10:36 PM
#10
Thanks for the endorsements for my article. It's getting kind of out of date though. For one thing, there is no need for shielded wire from the pickups to the ignitors. I've never needed it, even with leaky plug wires.
That MSD article is even older. Do yourselves a favor and DON'T use two seperate coils. Get a DIS coil instead.
That MSD article is even older. Do yourselves a favor and DON'T use two seperate coils. Get a DIS coil instead.
01-26-13, 02:44 PM
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i just did the msd 6al and two blaster coils on the leading and a stocker on the trailing, i see no power increase at all, idle is the same, cold start the same little dissapointed. are you really suppost to move your trailing wires on the cap to your leading. i smell gas fumes more than before i did the swap and my so says it was smoking when first started and a small back fire. i put the blaster 2 coils in the stock location so there not standing up could this make a difference also seems like the trailing coil is getting pretty hot. can anyone help with this, should it have more power. (stock motor)
