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Tech: The 944 / 951 Ignition System.

 
Old 02-10-2013, 12:41 PM
  #16  
gregeast
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Great stuff Joshua, thanks as always for sharing your knowledge with the community.

While 'bigger is always better', or in this case 'more energy is always better', in the real world of our engines:

What's the advantage of more energy at higher revs?
Why is being able to run a wider spark plug gap an advantage?
Any effect on emissions from this?

Just curious!
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Old 02-10-2013, 12:54 PM
  #17  
Adker
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MSD makes a 6ALN Ignition Control ignition module that drive this coil, no need to worry about cooking the DME. The MSD Blaster HVC II Coil PN 8253 is the preferred coil for this unit.

Last edited by Adker; 05-16-2013 at 10:10 PM.
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Old 02-10-2013, 01:31 PM
  #18  
refresh951
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Originally Posted by Adker View Post
MSD makes a 6ALN Ignition Control ignition module that drive this coil, no need to worry about cooking the DME. The MSD Blaster HVC II Coil PN 8253 is the preferred coil for this unit.
If you can change the dwell map there is no need for the the 6A. The DME/ HVC-II (with proper dwell map) will out perform it according to Rogue.

Last edited by refresh951; 02-10-2013 at 06:44 PM.
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Old 02-10-2013, 02:14 PM
  #19  
blown 944
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As always, above and beyond...

As I've said before, I fell very fortunate to be involved (in a limited capacity) and witness to what goes on in your office. Funny though, most times, you're speaking greek to me and showing me with your test equiptment.


In the end... Like the infamous Ricky Bobby.... I just wanna go fast.

Thanks!!
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Old 02-10-2013, 02:15 PM
  #20  
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Originally Posted by Adker View Post
MSD makes a 6ALN Ignition Control ignition module that drive this coil, no need to worry about cooking the DME. The MSD Blaster HVC II Coil PN 8253 is the preferred coil for this unit.
The 6ALN is $315... Plus you have to figure out where to mount another piece of hardware in an already cluttered engine bay.

The stock DME can run the HVC II coil with no additional hardware (Josh just explained how, and with no danger to the DME). So you buy the M-tune (Which you want anyway), and the coil....and you're done.
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Old 02-10-2013, 06:08 PM
  #21  
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Originally Posted by Eric_Oz_S2 View Post
Joshua

Thanks or the write up, very interesting. So does the higher coil energy result in any measurable increase in spark duration and combustion efficiency? I always wondered whether these MSD kits really made a difference. It's not like a twin spark head in the 911 derivatives with the dual distributors, which do make some difference in power output.
Originally Posted by 964-C2 View Post
+1
On an inductive ignition, higher energy should translate into longer spark duration (all things else remaining equal).

During the combustion stroke, the air/fuel mixture is swirling, tumbling, and generally anything but still. This means having a longer spark duration has the possibility of igniting multiple areas of the air/fuel mixture as it passes by the spark-plug. This is similar to lighting a camp-fire in multiple spots, opposed to one spot. By lighting the air/fuel mixture in multiple areas, the flame-front is improved, which results in a faster combustion. This means the engine needs less timing advance; less timing advance means less "negative work" of the combustion process resisting the pistons upward movement.

The MSD ignition boxs are a capacitive ignition system. This is different than our inductive ignition. On our cars, the energy to fire the spark-plug is developed, and stored in the coil (an inductor). The MSD box uses capacitors to store the energy.
In an inductive system, it will only develop the minimum voltage necessary to jump the spark-plug gap. Any remaining energy (current) is then used to sustain the spark (spark-duration).
In a capacitive system, the ignition box sends a very high primary voltage to the coil (can be >500volts). The coil isn't really used to store any energy - rather it is only used as a transformer, to bump up voltage. With the capacitive system, there is a lot of voltage, but no real current. The result is that the MSD box might be able to jump a larger gap, but the spark duration is typically much shorter than an inductive ignition. This is a problem - even if the voltage is really high, that does not guarantee that the air/fuel will ignite; you need time for the spark to heat the air/fuel.

Originally Posted by URG8RB8 View Post
Does this mean the Rogue Tuning penultimate ignition kit is going to be available soon? You know I have been waiting a long time for this!
Perhaps... This is more to show Rogue Tuning customers that they have options for improving their ignition system. (I don't currently have plans to carry either the Blaster or HVC-II coil)

Originally Posted by MooreBoost View Post
josh you the man!!!
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Old 02-10-2013, 06:12 PM
  #22  
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Originally Posted by refresh951 View Post
Great information! Thanks to Joshua I have my ignition setup covered for the Ultra Stroker Build. The Blaster Coil is going to allow me to run the timing I want to keep the motor very crisp. He once again gives an outstanding solution that is very reasonable from a cost standpoint.

I must say that Joshua's knowledge goes FAR BEYOND just tuning. He has some great insight into many areas concerning our cars. Not only has he made significant contributions to the platform, he has a genuine passion for the 951.
Thanks Shawn
BTW - I think you mean the HVC-II coil

Originally Posted by lart951 View Post
question how do I change the ignition dwell map to account for the HVC II col?
Lart, that is something only accessible in the DME software...

Originally Posted by URG8RB8 View Post
Josh:

Since I have not seen my car in so long, I am curious about the 23+ year old wire that supplies the coil with it's power. Would it be valuable/advisable to upgrade this to a better grade of OFC and possibly a larger AWG? Of course, it would be better still to upgrade both the supply and the ground if this is deemed advantageous. While we are discussing upgrades, I would be very interested in your opinion on the plug wires. I am sure there is a limit to their validity, or better stated at what point are we wasting our money on fancy wires. I see some rediculously large wires being installed on JDM cars that can't possible need a conductor that large. On the other hand, I am sure the 23+ year old OEM design can be improved upon.
Yes, ideally larger coil wire could be used to minimize resistance (and inductance).
Regarding plug-wires... spark-plug wires aren't really conducting any significant amperage - the main thing is that they can handle ~50kV.

Originally Posted by URG8RB8 View Post
Lart:

I assume you have M-tune and if so, you will need a reflash of your PROM from Josh.
Originally Posted by lart951 View Post
Thanks so it's not something you can do without a M-tune
Changing the ignition dwell map requires adjustment in the software.
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Old 02-10-2013, 06:17 PM
  #23  
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Originally Posted by URG8RB8 View Post
I have had this monster in my 300ZX and RX-7 turbo for 15+ years. I would be interested to see what it has for output and charge time.
Ha - Sid actually has that coil, and as soon as I can get a hold of it, I will test it out and see how good (or not) it is!

Originally Posted by reno808 View Post
Nice... thanks for sharing. Too bad other vendors do not do this


Originally Posted by gregeast View Post
Great stuff Joshua, thanks as always for sharing your knowledge with the community.

While 'bigger is always better', or in this case 'more energy is always better', in the real world of our engines:

What's the advantage of more energy at higher revs?
Why is being able to run a wider spark plug gap an advantage?
Any effect on emissions from this?

Just curious!
Greg, I think my previous posts answered your first couple of questions. (let me know if they need further clarification)
Regarding emissions - there should be an improvement due to a better, more complete combustion process...
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Old 02-10-2013, 06:20 PM
  #24  
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Originally Posted by Adker View Post
MSD makes a 6ALN Ignition Control ignition module that drive this coil, no need to worry about cooking the DME. The MSD Blaster HVC II Coil PN 8253 is the preferred coil for this unit.
Originally Posted by refresh951 View Post
If you can change the dwell map there is no need for the the 6A. The DME/Blaster (with proper dwell map) will out perform it according to Rogue.
Originally Posted by m73m95 View Post
The 6ALN is $315... Plus you have to figure out where to mount another piece of hardware in an already cluttered engine bay.

The stock DME can run the HVC II coil with no additional hardware (Josh just explained how, and with no danger to the DME). So you buy the M-tune (Which you want anyway), and the coil....and you're done.
The MSD 6 series has 110mJ - 135mJ of energy each ignition event. The HVC-II coil, with the factory DME is over 200mJ for each ignition event...

So you can have >200mJ or 135mJ? I know which one I will choose.
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Old 02-10-2013, 08:30 PM
  #25  
Tom M'Guinn
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Here is that coil with an MSD 6A box. I have to say it makes a noticeable difference over the stock ignition, especially at higher boost levels. I also have an M&W Pro-10 box, which puts out slightly more energy, but must say the MSD stuff has had more than enough spark for anything I've thrown at it. There are boxes out there that make 250mJ or more, but I haven't found that needed yet, and worry that kind of energy would burn out plugs, caps and rotors pretty quick? Getting rid of the extra box and using the re-dwelled DME is appealing though...
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Old 02-10-2013, 08:43 PM
  #26  
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Tom:

To your burn out the plugs statement, it is quite early here and I need to research a little more, but I remember Rick Cannell telling me to be very careful on my plug selection using the MSD DIS-4 HO in conjunction with the COP setup I have. He did not have the HO version and melted the electrodes off his plugs. He told me that I would most likely have to use RX-7 style electrodeless plugs that fire off the crowns of the pistons, also used frequently in OB boat motors. This is a great thread!
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Old 02-10-2013, 09:17 PM
  #27  
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Originally Posted by Rogue_Ant View Post
Regarding plug-wires... spark-plug wires aren't really conducting any significant amperage - the main thing is that they can handle ~50kV.
Very interesting, much as I expected! Therefore, other than looks and possible heat protection from larger silicone outers, you aren't gaining squat from big expensive wires. Thanks for the quick reply! I might wait a few week's to see if Sid will let you test his Ultra coil as I have a spare burried in the FL attic somewhere. I bought the entire Jacob's ignition system back in 1990 for the Z, it was over a grand, big money back then and I was still a student. I noticed that it shipped with fairly small (8mm) wires and wrote them a letter(yes, by hand snail mail, damn I am old) about it and was told the same thing, more than you will ever need.
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Old 02-10-2013, 09:23 PM
  #28  
blown 944
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I will tell you that with the Jacobs coil I still need the msd to prevent blow out at high boost.

So in other words, I wouldn't expect much.
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Old 02-10-2013, 09:29 PM
  #29  
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Very interesting, I've been running the MSD coil blaster from the beginning.. So i can't compair it to the factory coil.

P.S I added this to the sticky!
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Old 02-10-2013, 09:48 PM
  #30  
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Originally Posted by blown 944 View Post
I will tell you that with the Jacobs coil I still need the msd to prevent blow out at high boost.

So in other words, I wouldn't expect much.

Sid:

Were you just ultilizing the coil or the complete system. This coil was designed to be used with a controller similar to the MSD controller mentioned above. I managed to locate a lousy quality pic of the complete system.
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