Ignition coil compatibilility
04-01-2013, 05:44 PM
#16
Drifting
"Used in the USAF FPS-3 & 6 dewline ground radar to fire the RADAR transmitting magnetron."
Totally applicable to a Porsche/Bosch CDI system, right?
Theoritically, yes, YES! Even practically provided you have a basic understanding of electronic, something Loren, sorry to say, obviously lacks.
"I think this merits posting."
Not really! More erroneous info found on internet.
Again, for the naive who believe everything posted and written from day
one, including that the earth at one point was thought to be not round,
not all internet info is always applicable/correct. One can always find
old-wives-tails to quote.
Bottom line: Keep 'digging-up' and posting hyperbole
with NO technical understanding of the issue! Maybe,
Speaking of....
try sticking to posts about what's the best car wax.
Actually, using a conventional TCI coil results in less stress (lower peak currents) to the CDI output stage (the SCR & the capacitor) in most cases.
No, Loren. At high engine RPM the TCI coil needs to have LOW inductance along with high "Q" in order for the value of the stored energy to rise high enough in the short time allowed. On the other hand since the CDI coil's primary voltage rises INSTANTLY to the maximum there is no need for a really high "Q" coil inductance.
Remember:
1/2 I * I * L (primary of coil) = 1/2 V * V * C (CDI capacitor)
Conventional coils (TCI) have higher primary inductance as they store the
energy for the spark versus the CDI capacitor which stores the energy.
This results in lower peak currents for the capacitor & SCR in the CDI
type of ignition reducing its potential failure rate.
Oh, now I get it...equivalent to applying 250 volts to the primary vs the regular 300 volts. Yes, less stress on gteh SCR but with a result of not always firing the plug.
Loren, lower current flow in the primary coil of a CDI ignition will ALWAYS result in a shorter arc duration, if you get an ARC at all since the secondary voltage risetime will be slower due to the increased primary inductance.
Again, the coil in a CDI
system is only a transformer used to transfer the energy from the capacitor.
The TCI coil still functions as a transformer just like a CDI coil does.
Yes, it does, but at what turns ratio? And what about the structure of the magnetic path internally? E & I core or simple "I"? For CDI to work properly the primary windings must be tight coupled magnetically to the secondary, while the TCI coil does not.
When solving the above equation for I (peak current), one finds that
the current is reduced with the larger primary inductance of the TCI
(conventional) coil. Many use the Bosch blue coil as a replacement
for the original Bosch CDI coil.
Totally applicable to a Porsche/Bosch CDI system, right?
Theoritically, yes, YES! Even practically provided you have a basic understanding of electronic, something Loren, sorry to say, obviously lacks.
"I think this merits posting."
Not really! More erroneous info found on internet.
Again, for the naive who believe everything posted and written from day
one, including that the earth at one point was thought to be not round,
not all internet info is always applicable/correct. One can always find
old-wives-tails to quote.
Bottom line: Keep 'digging-up' and posting hyperbole
with NO technical understanding of the issue! Maybe,
Speaking of....
try sticking to posts about what's the best car wax.
Actually, using a conventional TCI coil results in less stress (lower peak currents) to the CDI output stage (the SCR & the capacitor) in most cases.
No, Loren. At high engine RPM the TCI coil needs to have LOW inductance along with high "Q" in order for the value of the stored energy to rise high enough in the short time allowed. On the other hand since the CDI coil's primary voltage rises INSTANTLY to the maximum there is no need for a really high "Q" coil inductance.
Remember:
1/2 I * I * L (primary of coil) = 1/2 V * V * C (CDI capacitor)
Conventional coils (TCI) have higher primary inductance as they store the
energy for the spark versus the CDI capacitor which stores the energy.
This results in lower peak currents for the capacitor & SCR in the CDI
type of ignition reducing its potential failure rate.
Oh, now I get it...equivalent to applying 250 volts to the primary vs the regular 300 volts. Yes, less stress on gteh SCR but with a result of not always firing the plug.
Loren, lower current flow in the primary coil of a CDI ignition will ALWAYS result in a shorter arc duration, if you get an ARC at all since the secondary voltage risetime will be slower due to the increased primary inductance.
Again, the coil in a CDI
system is only a transformer used to transfer the energy from the capacitor.
The TCI coil still functions as a transformer just like a CDI coil does.
Yes, it does, but at what turns ratio? And what about the structure of the magnetic path internally? E & I core or simple "I"? For CDI to work properly the primary windings must be tight coupled magnetically to the secondary, while the TCI coil does not.
When solving the above equation for I (peak current), one finds that
the current is reduced with the larger primary inductance of the TCI
(conventional) coil. Many use the Bosch blue coil as a replacement
for the original Bosch CDI coil.
04-01-2013, 08:46 PM
#18
"I think this is why they do NOT recomend a lower resistance coil ( used in CDI ignition ) as this will allow more current to flow and burn out the TCI module eventually."
That's exactly correct which was indicated in my initial post.
"Yes, if you're willing to sacrifice more reliable plug firing for (needed?) additional SCR life, then go for it."
Another mis-statement, the energy is stored in the capacitor in a CDI
system and is NOT a function of the coil used. The coil is ONLY an energy transfer
device, not like the TCI ignition where the coil stores the energy initially.
Also, the rise time of the spark, i.e. for fouled plugs, is NOT a function of
the coil type either in a CDI system where it IS in a TCI ignition. That's
one of the reasons Porsche used a CDI ignition in its early cars. Now the
TCI type ignition can provide fast rise sparks as a result of faster semiconductors
which can also handle higher coil currents. So as most are aware, the 911
3.2 and ALL later Porsches no longer use CDIs.
"Dont both CDI and TCI coils act as step us transformers ? my undertsanding is they would have to ."
Again, you are absolutely correct. Both systems step-up the primary
voltage typically 90 - 100 times. So if the primary of either coil has
a peak voltage of 350 volts, the secondary could reach 35KV.
"Keeping in mind my original question .. can i use a Carrera type coil in my SC ?"
Yes, the problem is finding the original black coil, as most suppliers provide
the silver Brazilian coils, so you are potentially 'in the same boat'.
That's exactly correct which was indicated in my initial post.
"Yes, if you're willing to sacrifice more reliable plug firing for (needed?) additional SCR life, then go for it."
Another mis-statement, the energy is stored in the capacitor in a CDI
system and is NOT a function of the coil used. The coil is ONLY an energy transfer
device, not like the TCI ignition where the coil stores the energy initially.
Also, the rise time of the spark, i.e. for fouled plugs, is NOT a function of
the coil type either in a CDI system where it IS in a TCI ignition. That's
one of the reasons Porsche used a CDI ignition in its early cars. Now the
TCI type ignition can provide fast rise sparks as a result of faster semiconductors
which can also handle higher coil currents. So as most are aware, the 911
3.2 and ALL later Porsches no longer use CDIs.
"Dont both CDI and TCI coils act as step us transformers ? my undertsanding is they would have to ."
Again, you are absolutely correct. Both systems step-up the primary
voltage typically 90 - 100 times. So if the primary of either coil has
a peak voltage of 350 volts, the secondary could reach 35KV.
"Keeping in mind my original question .. can i use a Carrera type coil in my SC ?"
Yes, the problem is finding the original black coil, as most suppliers provide
the silver Brazilian coils, so you are potentially 'in the same boat'.
04-02-2013, 02:22 AM
#20
Drifting
"I think this is why they do NOT recomend a lower resistance coil ( used in CDI ignition ) as this will allow more current to flow and burn out the TCI module eventually."
That's exactly correct which was indicated in my initial post.
"Yes, if you're willing to sacrifice more reliable plug firing for (needed?) additional SCR life, then go for it."
Another mis-statement, the energy is stored in the capacitor in a CDI
system and is NOT a function of the coil used.
The coil is ONLY an energy transfer
Yes, ONLY an energy transfer device, with primary coil resistance, inductance, turns ratio, magnetic coupling primary to secondary having no importance whatsoever.
device, not like the TCI ignition where the coil stores the energy initially.
Also, the rise time of the spark, i.e. for fouled plugs, is NOT a function of
the coil type either in a CDI system
Sure, the CDI coil's primary resistance, inductance, and magnetic coupling efficiency to the secondary winding have NO influence on the rate of voltage rise in teh secondary, In your dreams...!!
where it IS in a TCI ignition. That's one of the reasons Porsche used a CDI ignition in its early cars.
Now the TCI type ignition can provide fast rise sparks as a result of faster semiconductors
BS to that. The kettering system used a parallel condensor across the points to PREVENT fast rise times. If the inductive "kick" primary voltage rose to quickly a flashover across the "slowly" opening points would often result. With the advent of transisstorized Kettering system the fast inductive voltage risetime became a non-issue regardless of the transistor turn-off time, rate.
Eliminating the need for the condensor resulted in relatively infinite inductive coil voltage risetime.
which can also handle higher coil currents.
Sorry, no, absolutely not. The distributor points when closed have virtually ZERO resistance, and thereby no IC (collector current) design limitation. I can show you many 12 volt electronic designs that use a relay contact for the highest current flow (highest 12 volt blower.fan speed), lowest switch "on" resistance, with transistors used for lower current flow ratings.
So as most are aware, the 911
3.2 and ALL later Porsches no longer use CDIs.
"Dont both CDI and TCI coils act as step us (up) transformers ? my undertsanding is they would have to ."
Again, you are absolutely correct. Both systems step-up the primary
voltage typically 90 - 100 times. So if the primary of either coil has
a peak voltage of 350 volts, the secondary could reach 35KV.
Again, with a CDI the turns ratio determines the MAXIMUM secondary voltage, with TCI the secondary voltage might rise to infinity if no "discharge" path, arc-over or leakage, is reached.
"Keeping in mind my original question .. can i use a Carrera type coil in my SC ?"
NO..!!Yes, the problem is finding the original black coil, as most suppliers provide
the silver Brazilian coils, so you are potentially 'in the same boat'.
That's exactly correct which was indicated in my initial post.
"Yes, if you're willing to sacrifice more reliable plug firing for (needed?) additional SCR life, then go for it."
Another mis-statement, the energy is stored in the capacitor in a CDI
system and is NOT a function of the coil used.
The coil is ONLY an energy transfer
Yes, ONLY an energy transfer device, with primary coil resistance, inductance, turns ratio, magnetic coupling primary to secondary having no importance whatsoever.
device, not like the TCI ignition where the coil stores the energy initially.
Also, the rise time of the spark, i.e. for fouled plugs, is NOT a function of
the coil type either in a CDI system
Sure, the CDI coil's primary resistance, inductance, and magnetic coupling efficiency to the secondary winding have NO influence on the rate of voltage rise in teh secondary, In your dreams...!!
where it IS in a TCI ignition. That's one of the reasons Porsche used a CDI ignition in its early cars.
Now the TCI type ignition can provide fast rise sparks as a result of faster semiconductors
BS to that. The kettering system used a parallel condensor across the points to PREVENT fast rise times. If the inductive "kick" primary voltage rose to quickly a flashover across the "slowly" opening points would often result. With the advent of transisstorized Kettering system the fast inductive voltage risetime became a non-issue regardless of the transistor turn-off time, rate.
Eliminating the need for the condensor resulted in relatively infinite inductive coil voltage risetime.
which can also handle higher coil currents.
Sorry, no, absolutely not. The distributor points when closed have virtually ZERO resistance, and thereby no IC (collector current) design limitation. I can show you many 12 volt electronic designs that use a relay contact for the highest current flow (highest 12 volt blower.fan speed), lowest switch "on" resistance, with transistors used for lower current flow ratings.
So as most are aware, the 911
3.2 and ALL later Porsches no longer use CDIs.
"Dont both CDI and TCI coils act as step us (up) transformers ? my undertsanding is they would have to ."
Again, you are absolutely correct. Both systems step-up the primary
voltage typically 90 - 100 times. So if the primary of either coil has
a peak voltage of 350 volts, the secondary could reach 35KV.
Again, with a CDI the turns ratio determines the MAXIMUM secondary voltage, with TCI the secondary voltage might rise to infinity if no "discharge" path, arc-over or leakage, is reached.
"Keeping in mind my original question .. can i use a Carrera type coil in my SC ?"
NO..!!Yes, the problem is finding the original black coil, as most suppliers provide
the silver Brazilian coils, so you are potentially 'in the same boat'.
04-02-2013, 09:54 AM
#22
Team Owner
Thread Starter
Well i posted for what i thought was a simple question apparently not so simple.
Anyway Loren i have found the SC coil to be none available ( yup the brazillian crap of course is ) . but the Carrera coil is available . i dont think it uses the Brazillion crap coil , that was why i posed the question initially.
So here is the follow up question. I have heard mention that my only real option is to buy a used one from an SC . is there anyway to tell visually or otherwise ( at a swap meet for example) which type of coil is which ?
Thanks .
Anyway Loren i have found the SC coil to be none available ( yup the brazillian crap of course is ) . but the Carrera coil is available . i dont think it uses the Brazillion crap coil , that was why i posed the question initially.
So here is the follow up question. I have heard mention that my only real option is to buy a used one from an SC . is there anyway to tell visually or otherwise ( at a swap meet for example) which type of coil is which ?
Thanks .
04-02-2013, 12:27 PM
#23
"So here is the follow up question. I have heard mention that my only real option is to buy a used one from an SC . is there anyway to tell visually or otherwise ( at a swap meet for example) which type of coil is which ?"
As was mentioned, many buy the blue Bosch coil and use it.
You can use the info found here under 'Typical Ignition Coil Values';
http://www.systemsc.com/diagnostic.htm
There are a lot options for coils shown there.
If you have further questions, you can always just call the number
on the website.
As was mentioned, many buy the blue Bosch coil and use it.
You can use the info found here under 'Typical Ignition Coil Values';
http://www.systemsc.com/diagnostic.htm
There are a lot options for coils shown there.
If you have further questions, you can always just call the number
on the website.
04-02-2013, 02:01 PM
#25
Drifting
"So here is the follow up question. I have heard mention that my only real option is to buy a used one from an SC . is there anyway to tell visually or otherwise ( at a swap meet for example) which type of coil is which ?"
As was mentioned, many buy the blue Bosch coil and use it.
You can use the info found here under 'Typical Ignition Coil Values';
http://www.systemsc.com/diagnostic.htm
There are a lot options for coils shown there.
If you have further questions, you can always just call the number
on the website.
As was mentioned, many buy the blue Bosch coil and use it.
You can use the info found here under 'Typical Ignition Coil Values';
http://www.systemsc.com/diagnostic.htm
There are a lot options for coils shown there.
If you have further questions, you can always just call the number
on the website.
http://www.centuryperformance.com/fo...tion-Coil-Tech
Search (IE) for "cannister' and read the sentence containing the 4th "hit".
04-02-2013, 02:10 PM
#26
Drifting
Well i posted for what i thought was a simple question apparently not so simple.
Anyway Loren i have found the SC coil to be none available ( yup the brazillian crap of course is ) . but the Carrera coil is available . i dont think it uses the Brazillion crap coil , that was why i posed the question initially.
So here is the follow up question. I have heard mention that my only real option is to buy a used one from an SC . is there anyway to tell visually or otherwise ( at a swap meet for example) which type of coil is which ?
Thanks .
Anyway Loren i have found the SC coil to be none available ( yup the brazillian crap of course is ) . but the Carrera coil is available . i dont think it uses the Brazillion crap coil , that was why i posed the question initially.
So here is the follow up question. I have heard mention that my only real option is to buy a used one from an SC . is there anyway to tell visually or otherwise ( at a swap meet for example) which type of coil is which ?
Thanks .
Like "this" one but shop around for price.
http://www.google.com/url?sa=t&rct=j...JrH82X_bUKMKLQ
Last edited by wwest; 04-02-2013 at 02:42 PM.
04-02-2013, 06:44 PM
#29
Team Owner
Thread Starter
