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Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: lockjaw-express] #2480206
04/09/18 10:20 PM
04/09/18 10:20 PM
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Milwaukee WI
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TRENDZ Offline
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I would suggest lowering that 4.5 ms time below and above peak tq. In most engine conditions other than high load, 2ms would be sufficient and be easier on the coils.


"use it 'till it breaks, replace as needed"
Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: TRENDZ] #2480245
04/09/18 11:06 PM
04/09/18 11:06 PM
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Romeo MI
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Originally Posted By TRENDZ
No just the opposite. The CDI is the shojavascript:%20void(0)
Quote:
rt duration, high energy start. The inductive sparkis the long duration trail.
This is why MSD has multiple sparks below 3000 rpm. The short duration CDI spark would not burn up themixture fully at low rpms.

As far as plug gap, you can run it wide... but you end up with a much shorter spark duration doing so. The wider the gap, the more you stress the coil/ wires/ plugs.
The Ign1 coils are capable of burning holes through some spark plug insulators. Much better to take it easy on the hard parts and turn the energy into duration.


I'll try it.. my plugs are out right now.. so its
a good time to try it
wave

Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: TRENDZ] #2480253
04/09/18 11:33 PM
04/09/18 11:33 PM
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Romeo MI
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Rick, do I need to re-down load the V4 program
on my new puter or can I get it off the car
then save that.. I dont have it anywhere at the
present time
thanks
wave

Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: lockjaw-express] #2480281
04/10/18 12:02 AM
04/10/18 12:02 AM
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TRENDZ Offline
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You can get the software from the Holley website free. I haven’t checked if there are software updates since you changed yours. There is usually software update notes that tell you what has changed, or things you need to be aware of. READ THIS CAREFULLY.


"use it 'till it breaks, replace as needed"
Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: TRENDZ] #2480290
04/10/18 12:33 AM
04/10/18 12:33 AM
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Oregon
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Originally Posted By TRENDZ
I would suggest lowering that 4.5 ms time below and above peak tq. In most engine conditions other than high load, 2ms would be sufficient and be easier on the coils.


I set the dwell time at 4.5ms since that is what the Holley data sheet recommended for 1.5 hp/cubic inch. I can tighten up the plug gap and reduce the dwell time easy enough.

Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: TRENDZ] #2480295
04/10/18 12:48 AM
04/10/18 12:48 AM
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Romeo MI
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Ok got the new down load
wave

Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: lockjaw-express] #2480328
04/10/18 02:08 AM
04/10/18 02:08 AM
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Ohio
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lockjaw-express Offline OP
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Rick, The Holley Smart Coils also have a capacitor/condenser that charges, then gets discharged...so is that not a CDI? I always thought so.

The MSD has circutry that sends a pulse to the capacitor/capacitors that discharges multiple times, right?

I would think that having a fully charged single coil dedicated to each cylinder would discharge a hotter spark with a wider gap, and the MSD is a completely different animal altogether.

Where am I going wrong on this?

Does MSD make their own smart coils that do MSD like the larger units?

Mark


Last edited by lockjaw-express; 04/10/18 02:11 AM.
Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: lockjaw-express] #2480352
04/10/18 06:38 AM
04/10/18 06:38 AM
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The holley dominator/ hp ecu is set up to be able to control the timing and the dwell of each coil directly. No external box/ amplifier.
Each coli will be powered by the cars charging system voltage. Call it 12 volts. Each coil has a smart circuit looking for a hi and a low signal. There are also some internal self presevering features like a clamping diode set around 18 volts if I remember correctly. This is the maximum voltage that they will handle.

A CDI ignition box sends about 400 volts to the coil, then uses the coil as an amplifier. CDI coils are much different and are not interchangeable with inductive coils. The dominator/ hp ECUs don't directly control the coil with CDI. The ecu just tells the ignition box when to fire.

CDI gives a very strong very short duration spark. Much stronger than an inductive set up. The problem is duration. You need multiple events with CDI to be sure that the mixture lights. At higher rpm, there isnt time to charge multiple times. You could get around this I guess, by putting 8 msd boxes in and having multiple sparks at much higher rpm.


"use it 'till it breaks, replace as needed"
Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: lockjaw-express] #2480461
04/10/18 01:23 PM
04/10/18 01:23 PM
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lockjaw-express Offline OP
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Hi Rick,

Thank you for the explanation...MSD does make some MSD Smart coils, and I will also look into those as well. I read a few reviews, and most were very good.

BTW, my Corvette C6 PWM controllers that you set me up with are working out great on both cars, however I am leaning on replacing the 160* thermostats with 180*. It seems that the engines could use the extra heat for moisture control, and less sludge problems.

Thanks, Mark

Last edited by lockjaw-express; 04/10/18 06:55 PM.
Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: lockjaw-express] #2480926
04/11/18 07:42 AM
04/11/18 07:42 AM
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I wouldn’t look any further. If you have the Holley coils(aka IGN1A), and you are running them directly from the ECU, you already have the best ignition for your application. The only step up would be some sort of all out magneto ignition.

It is my opinion that the benefits of CDI go away when the multiple spark drops out, and those benefits don’t return until over 9000+ rpm. The benefit being full, “adequate length” spark.

Both CDI and inductive have pluses and minuses. The rpm and hp range that most people operate their engines in would be best suited with a multi coil inductive set up. That’s just my opinion.


"use it 'till it breaks, replace as needed"
Re: Holley HP EFI Coil Near Plug Spark Plug Gap [Re: lockjaw-express] #2481005
04/11/18 11:37 AM
04/11/18 11:37 AM
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Tulsa OK
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I have heard of reliability issues with the MSD individual coils. I think stock GM coils or IGN1A coils are the ticket for reliability and power.

This was an interesting thread, I am about the change plugs in my car and I will close the gap up some(I think they are at .40). I run the GM truck coils.


68 Barracuda Formula S 340
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