Rbob
Well-Known Member
Can someone explain why / why not use the pertronix III coil, it is supposed to work with HEI type ignition, Its been said over and over again to use E-core when converting to HEI.
E-core vs Pertronix III
- Thread starter Rbob
- Start date
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KitCarlson
Well-Known Member
I looked at the pertronix III specs, they list resistance of 0.32 Ohms and volts at 45KV. Just that information is not useful. It is a canister coil, so will look more original in an older MOPAR. If they listed the inductance that would be helpful for use in calculation of the spark energy and charge time. Typically an E-Core design has less leakage inductance, so is more efficient in the magnetic circuit coupling design. The HEI auto-dwell-time and current limit, controls the coil charge current, not so much the coil resistance. Typical E-core resistances are 0.5 Ohms. So without seriously testing, I have little idea of the performance capability.
Rbob
Well-Known Member
This is what I found on the instructions:
Caution: Flame-Thrower III 0.32 coils should not be used with the (original) Ignitor, Ignitor II or point type ignition system. Flame-Thrower III coils are only
compatible with Ignitor III ignition systems, and most Capacitive Discharge (CD) systems that control the dwell period, or limit the current.
BALLAST RESISTOR or RESISTANCE WIRE
The ballast resistor needs to be removed if the Flame-Thrower III coil is used with the Ignitor III, or any Capacitive Discharge (CD) system that controls dwell or limits the current. This only applies to Ignitor III, or Capacitive Discharge systems
I bought a 4-pin Dyna Module hei type. The Dyna-Module has more electronic dwell in it to provide more coil saturation time. probably the same as most HEI modules.
Have to mount it on the firewall anyway, won't mount to Weiand 8022.
Just thinking (over thinking, again) about going with e-core.
What would you do?
Looked at this one: [ame="http://www.ebay.com/itm/12-VOLT-EXTERNAL-IGNITION-COIL-E-CORE-STYLE-BLACK-6930-BK-/330859297347?pt=Motors_Car_Truck_Parts_Accessories&hash=item4d08c03a43&vxp=mtr"]12 Volt External Ignition Coil E Core Style Black 6930 BK | eBay[/ame]
Caution: Flame-Thrower III 0.32 coils should not be used with the (original) Ignitor, Ignitor II or point type ignition system. Flame-Thrower III coils are only
compatible with Ignitor III ignition systems, and most Capacitive Discharge (CD) systems that control the dwell period, or limit the current.
BALLAST RESISTOR or RESISTANCE WIRE
The ballast resistor needs to be removed if the Flame-Thrower III coil is used with the Ignitor III, or any Capacitive Discharge (CD) system that controls dwell or limits the current. This only applies to Ignitor III, or Capacitive Discharge systems
I bought a 4-pin Dyna Module hei type. The Dyna-Module has more electronic dwell in it to provide more coil saturation time. probably the same as most HEI modules.
Have to mount it on the firewall anyway, won't mount to Weiand 8022.
Just thinking (over thinking, again) about going with e-core.
What would you do?
Looked at this one: [ame="http://www.ebay.com/itm/12-VOLT-EXTERNAL-IGNITION-COIL-E-CORE-STYLE-BLACK-6930-BK-/330859297347?pt=Motors_Car_Truck_Parts_Accessories&hash=item4d08c03a43&vxp=mtr"]12 Volt External Ignition Coil E Core Style Black 6930 BK | eBay[/ame]
TrailBeast
AKA Mopars4us on Youtube
Looks like a personal preference to me, outside of what Kit mentioned.
Is there a mention of an altered plug gap anywhere with the Flamethrower?
The HEI users have a gap of .045-.050 to take advantage of the hotter longer spark capability of the ecoils.
If the kv rating on the Flamethrower it should also be able to run a big gap.
They do mention a new design for dwell, and the output voltages are apparently the same.
Is there a mention of an altered plug gap anywhere with the Flamethrower?
The HEI users have a gap of .045-.050 to take advantage of the hotter longer spark capability of the ecoils.
If the kv rating on the Flamethrower it should also be able to run a big gap.
They do mention a new design for dwell, and the output voltages are apparently the same.
KitCarlson
Well-Known Member
The problem with more claims "saturation time", is that is not possible at higher RPM there is only so much available time regardless. In a V8 there are 4 sparks per engine revolution. That means 2.5mS between events at 6000 RPM. In that interval both dwell and spark needs to happen. Most coils need few mS to charge, and spark duration can also take a few mS. So at higher RPM spark duration is terminated early, this aids some in building coil current. At low and moderate RPM, time is available, but unnecessary dwell extension heats the coil, and may result in excessive peak currents and associated noise problems.
As I said in my first post what is needed, is know the coil inductance. The more inductance, the higher the stored energy, but also results slower charge rate. Stored energy goes up as the square of the current times the inductance, so lower inductance can result in more energy if the current builds faster.
Either coil will likely work well. I fabricated my own mount to mount an E-core on standard intake bolt locations. I have experimented with a Ford TFI E-Core, it was good for me. I do not expect high RPM capability.
Either coil may work better than stock and be good enough for on road driving.
As I said in my first post what is needed, is know the coil inductance. The more inductance, the higher the stored energy, but also results slower charge rate. Stored energy goes up as the square of the current times the inductance, so lower inductance can result in more energy if the current builds faster.
Either coil will likely work well. I fabricated my own mount to mount an E-core on standard intake bolt locations. I have experimented with a Ford TFI E-Core, it was good for me. I do not expect high RPM capability.
Either coil may work better than stock and be good enough for on road driving.
Usually when talking "saturation time" for ignition coils or control modules the unit of measure isn't fractions of a second, it is crank degrees. Since dwell angle is usually also mentioned in the same breath it makes me wonder if they really know what they're talking about. If they do, why the confusing units?
There is no debating that the max rate of charge for a coil or anything else is in 'real' time units; milli-, micro-, pico-seconds or whatever other fractional second unit makes the most sense to use.
Maybe Kettering was wrong and Henry Ford was doing it the right way all along?
There is no debating that the max rate of charge for a coil or anything else is in 'real' time units; milli-, micro-, pico-seconds or whatever other fractional second unit makes the most sense to use.
Maybe Kettering was wrong and Henry Ford was doing it the right way all along?
KitCarlson
Well-Known Member
Dwell in degrees is rediculous. Time in degrees varies with RPM, so the balast resistor is added as a cheap fix. Then came electronics, but Mopar kept it cheap and simple and did not implement dwell control. HEI controls dwell in an analog fashion, to charge the coil based on prior ignition event. Micro controllers do a better job, because controlling time requires logical adjustments to hit the ever changing target.
Most think in terms of R C time constant, but for inductors it is L/R. The maxium current is V/R. For a 0.32 Ohm coil at 13.8V, the maximum current could reach 43A. However the coil is likely able to tolerate 5 to 7A long term. Ignitions without balast must accurately limit the charge time to limit the current, or use the switch in the active mode. Most use both, but limit the active mode , because it heats the switch, just like a balast gets hot. Active dwell control has the most difficulty at low RPM. An example is at 800 RPM, there is about 19mS of available time for coil charge and ignition. If it takes 3mS to charge the coil, that must be done just before use in a predictive manner. The solution is to charge early, to accomodate timing advance ramp, and RPM fluctuations on take off. When charging early the desired coil current is held to the desired value. There are ways to PWM control current to that reduce power dissipated in switch.
V8 and one coil is a compromise at high RPM. While MSD CDI provides higher peak energy, the spark duration is very short. The modern solution is coil per plug.
Most think in terms of R C time constant, but for inductors it is L/R. The maxium current is V/R. For a 0.32 Ohm coil at 13.8V, the maximum current could reach 43A. However the coil is likely able to tolerate 5 to 7A long term. Ignitions without balast must accurately limit the charge time to limit the current, or use the switch in the active mode. Most use both, but limit the active mode , because it heats the switch, just like a balast gets hot. Active dwell control has the most difficulty at low RPM. An example is at 800 RPM, there is about 19mS of available time for coil charge and ignition. If it takes 3mS to charge the coil, that must be done just before use in a predictive manner. The solution is to charge early, to accomodate timing advance ramp, and RPM fluctuations on take off. When charging early the desired coil current is held to the desired value. There are ways to PWM control current to that reduce power dissipated in switch.
V8 and one coil is a compromise at high RPM. While MSD CDI provides higher peak energy, the spark duration is very short. The modern solution is coil per plug.
Rbob
Well-Known Member
Thanks for the replies, lots of knowledge and help to be had, its what makes this sight so great.
Without knowing the inductance of the pertronix III its still a crap shoot for me. Seems to me the e-core would still be better suited, especially at high rpm.
So more thinking for me.
Without knowing the inductance of the pertronix III its still a crap shoot for me. Seems to me the e-core would still be better suited, especially at high rpm.
So more thinking for me.
Rbob
Well-Known Member
So snooping around found pertronix 40011 list inductance... not listed as a flamethrower II or III
specs:
Coil Style:Canister
Primary Resistance:1.500 ohms
Coil Internal Construction:Oil-filled
Coil Color:Black
Maximum Voltage:40,000 V
Turns Ratio:115:1
Secondary Resistance:10.6K ohms
Inductance:6.4 mH
Peak Current:7.2 amps
Spark Duration:1.5 mS
Wonder why they don't spec the III.
specs:
Coil Style:Canister
Primary Resistance:1.500 ohms
Coil Internal Construction:Oil-filled
Coil Color:Black
Maximum Voltage:40,000 V
Turns Ratio:115:1
Secondary Resistance:10.6K ohms
Inductance:6.4 mH
Peak Current:7.2 amps
Spark Duration:1.5 mS
Wonder why they don't spec the III.
TrailBeast
AKA Mopars4us on Youtube
At this point I would play it safe and for sure get the best spark available with the E core.
So much information with so little noticable difference in the car.
Dwell (angle) has always been in crank degrees. Goes back to the days of points ignitions. On the distributor machine (who remembers those? I want one if you know one for sale) we were taught to look for dwell angle stability and to work towards as stable and consistent as we could make it. Mopar dizzy's were always the worst for this. Their dwell angles would vary from one cylinder to the next by as much as 5°
A coil per cylinder is not new in the least. Henry Ford's Model T had it and each coil had it's own wooden box. By today's stds those coil boxes are works of art. It's distributor only switched the coils on and off, no high voltage distribution - that was Charles (?) Kettering's (GM Engineer) contribution to gasoline fueled engine ignition.
A coil per cylinder is not new in the least. Henry Ford's Model T had it and each coil had it's own wooden box. By today's stds those coil boxes are works of art. It's distributor only switched the coils on and off, no high voltage distribution - that was Charles (?) Kettering's (GM Engineer) contribution to gasoline fueled engine ignition.
KitCarlson
Well-Known Member
The dwell angle is all about using a mechanical cam to open and close points. A crude and incorrect method of charging a coil. A coil charges in a fixed amount of time based on supply voltage, inductance and resistance in the series circuit. The charge is not the maximum current unless limited by a ballast, but that limited by time of charge. The desired action is to charge the coil a precise time, not angle before it is needed.
The concern of dwell angle setting has to do with the percentage of point open and closed degrees with rotation of the distributor cam, and the point gap setting. The point gap setting also changes base timing, because of where on the ramp the points open, varies with gap. Dual point distributors use two sets of points to extend dwell at higher RPM, it is a means to get more closed and less open. It is a poor fix for a poor system, but when working with mechanical it is an option.
The best electronic ignition use Hall or optical sensing to provide crank reference points. The points are edges of an electronic signal not dependent on cam profile. The reference signals are then used by a micro contoller and other data for manifold pressure, temperatures, knock sensing... to control coil charge and ignition timing.
Working with ignitions is based on the physics of electricity. Inductors are controlled with voltage, switches, resistance and time. Using a scope to measure currents an voltage in the circuit reveals behavior. There are equations in both the time domain and frequecy domain that work well to evaluate behaviour.
The concern of dwell angle setting has to do with the percentage of point open and closed degrees with rotation of the distributor cam, and the point gap setting. The point gap setting also changes base timing, because of where on the ramp the points open, varies with gap. Dual point distributors use two sets of points to extend dwell at higher RPM, it is a means to get more closed and less open. It is a poor fix for a poor system, but when working with mechanical it is an option.
The best electronic ignition use Hall or optical sensing to provide crank reference points. The points are edges of an electronic signal not dependent on cam profile. The reference signals are then used by a micro contoller and other data for manifold pressure, temperatures, knock sensing... to control coil charge and ignition timing.
Working with ignitions is based on the physics of electricity. Inductors are controlled with voltage, switches, resistance and time. Using a scope to measure currents an voltage in the circuit reveals behavior. There are equations in both the time domain and frequecy domain that work well to evaluate behaviour.
KitCarlson
Well-Known Member
I made a simple circuit for pertronix coil per data with switch, no ballast resistor. I used that circuit in a simulator to plot the coil current vs time. The waveform is flipped, so consider that in the interpretation.
It takes about 9mS to charge the 1.5 Ohm, 6.4mH coil to 7.2A. With a 1.5mS spark duration the estimated engine RPM for an 8 cylinder engine is about 1400 RPM. RPM above that will result in less coil charge. Typically the spark duration is cut back to permit more coil charge. Typically 3A is often sufficient for reliable ignition. Specifications are sometimes marketing related to confuse, not really help those that need or the information.
It takes about 9mS to charge the 1.5 Ohm, 6.4mH coil to 7.2A. With a 1.5mS spark duration the estimated engine RPM for an 8 cylinder engine is about 1400 RPM. RPM above that will result in less coil charge. Typically the spark duration is cut back to permit more coil charge. Typically 3A is often sufficient for reliable ignition. Specifications are sometimes marketing related to confuse, not really help those that need or the information.
KitCarlson
Well-Known Member
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Rbob
Well-Known Member
Rbob
Well-Known Member
KitCarlson
Well-Known Member
Thanks for the leads.
I actually made a rudimentary one, by adding a needle at the base of distributor, degree wheel and timing light.
I also capture timings signals using a logic analyzer logger. That way is much more accurate than a distributor machine, no timing light lag. It is accurate to 50 parts per million, the crystal time base. I track the timing reference, and the coil drive, so RPM, coil charge time, ignition point and spark duration are easily measured in detail, for each ignition event.
My ECU user interface displays timing degrees, in real-time.
I actually made a rudimentary one, by adding a needle at the base of distributor, degree wheel and timing light.
I also capture timings signals using a logic analyzer logger. That way is much more accurate than a distributor machine, no timing light lag. It is accurate to 50 parts per million, the crystal time base. I track the timing reference, and the coil drive, so RPM, coil charge time, ignition point and spark duration are easily measured in detail, for each ignition event.
My ECU user interface displays timing degrees, in real-time.
[HIJACK]
I think the reason that this is 1/10th the price of others is because it's missing all of the instrumentation.Still tempting.... Could use my ancient Tektronix 475A for everything except the condensor meter.[/HIJACK]
TheMoparMan
Modifies everything
Go with the e core. The pertronix flame thrower si a crapshoot at best. I've dealt with pertronix flame thrower coils and their type I, II, and III modules with everything from Mopars, to fords to volkswagens and everything in between. Their products have too high of a failure rate for me. Having to go back and re- do work and listen to pissed off owners then contact pertronix for a replacement unit has soured me on their brand. If you get lucky and have one of the good units then by all means keep it. You may not be as lucky next time. Their stuff used to be great until they moved all manufacturing and quality control to china. Some Chinese factories are better than others but pertronix has got one of the cheap ones.... I usually try and steer people to MSD or if you want to go HEI DUI (Davis Unified Ignition) look for the USA made parts or at least USA quality control so you don't have to be the quality tester. There is some cheap ebay stuff but it's a crapshoot as to whether your actually getting the part described or a cheap Asian copy with questionable wiring and components inside. Remember you get what you pay for..... I personally have no problem with saving up for the more expensive quality part and look for warranties as well. If you use parts houses such as Oreileys, or Pep Boys, save the receipts as they will replace most stuff. And for a couple dollars more most times you can get the lifetime replacement. Just keep copies of receipts.
Rbob
Well-Known Member
Yes, going with e-core now, thanks to everyone here. Since I already had the DUI module I am going to stay with DUI and get their e-core "Inferno 2". Contacting them and get some specs first..
I will report back.
I will report back.
BigBlockMopar
BigBlockMember
Anyone running an e-core coil with a chrome Mopar ECU?
Does/will it work (long term)?
Does/will it work (long term)?
Rbob
Well-Known Member
Update! Changed my mind again... Ha ha
Went with the FBO HRR688 Ignition box and pertronix coil.
Talked to Don at 4-seconds flat, great guy and good salesman.
No complaints and love the rev limiter function.
Went with the FBO HRR688 Ignition box and pertronix coil.
Talked to Don at 4-seconds flat, great guy and good salesman.
No complaints and love the rev limiter function.
tekslk
Well-Known Member
I used trailbeast set up about 3 years now, very happy with it, Only wish I had a rev limiter.
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