Is the MSD Blaster igntion coil compatible with the CDI unit in the 1973.5T 911?

[wwest]

Originally Posted by uwanna

GREAT RESPONSE!! WWEST is kinda like the 14yr old adolescent who can tell you everything there is to know about sex because he's researched it on the internet, but has never experienced it! LOL

Built my first transistorized ignition in 1963.

First CDI I built was from a magazine design, ~1971...

Built several for friends.

Used a mis-matched impedance technique so the inverter wasn't shorted out.

[Jonny H]

I not sure what your point is. Sure, you can mess around with stuff and it may work.

All I'm saying is that the CDI was designed to be paired with a coil with certain characteristics. If it isn't, it won't be working as intended and something is therefore going to be different. It follows that if it is 'too' different, it will cause a problem. if you are really the EE guru, you'll know this to be true.

The implication of the OP's question was whether the MSD coil will work as the Bosch coil did. The answer is quite simple. If the specs are the same to a degree, then yes. If they are significantly different, then no.

You're splitting hairs and confusing people playing the 'superior knowledge' card all the time. it gets pretty boring pretty fast. It doesn't help people which is what this forum is meant to be about.

What annoyed me is you posted a link to an ebay TFI coil that has no specification cited. Therefore, how can you possibly say whether it is suitable for the application?

If, however, you actually ran that coil on your own car and posted up your findings and data you would get more credibility. Otherwise, you just look like a keyboard warrior.

Can you tell us your actual real world experience running CDI ignitons on a 911 please? Pictures and data would be great.

[wwest]

Originally Posted by Jonny H

I not sure what your point is. Sure, you can mess around with stuff and it may work.

All I'm saying is that the CDI was designed to be paired with a coil with certain characteristics. If it isn't, it won't be working as intended and something is therefore going to be different. It follows that if it is 'too' different, it will cause a problem. if you are really the EE guru, you'll know this to be true.

The implication of the OP's question was whether the MSD coil will work as the Bosch coil did. The answer is quite simple. If the specs are the same to a degree, then yes. If they are significantly different, then no.

You're splitting hairs and confusing people playing the 'superior knowledge' card all the time. it gets pretty boring pretty fast. It doesn't help people which is what this forum is meant to be about.

What annoyed me is you posted a link to an ebay TFI coil that has no specification cited. Therefore, how can you possibly say whether it is suitable for the application?

If, however, you actually ran that coil on your own car and posted up your findings and data you would get more credibility. Otherwise, you just look like a keyboard warrior.

Can you tell us your actual real world experience running CDI ignitons on a 911 please? Pictures and data would be great.

Your problem is, I think, as the primary aftermarket vendors state, most standard ignition coils have specs close enough that it doesn't matter.

Your argument rings a bit hollow since your own CDI+ document doesn't specify a specific coil nor a range of specification for selecting such.

[wwest]

My '78 911 Targa..

Data: It starts and runs well every time.

[wwest]

Originally Posted by Jonny H

I can't give an absolute yes or no to the OPs question as I haven't personally tested an MSD coil.

The CDI box and coil, although separate parts, are part of the same circuit so they are matched at design time. If the coil is changed to a different type with different characteristics, this could result in excess heat being generated in either the coil or the box. In extreme cases, the CDI output circuitry could be destroyed.

This is why most aftermarket ignitions require that you also use their coils.

You need to compare the MSD and original Bosch coil specifications for primary resistance, inductance and number of turns. See whether they are in the same ballpark.

It was my intention to prove the above statement as being in-correct.

Done. OUT.

[Jonny H]

^ A good start but a single picture isn't really sufficient to be 'done'. How about writing up a proper report? Install experience, traces, data, long term test results. 'It starts and runs every time' is not data.

On many occasions, you are quite scathing about other people's efforts and views. You ask them to 'prove it', and back it up with data. If you are going to serve up your solutions, by your own rules you must do the same. Make a positive contribution to this forum, start your own thread, instead of dragging others down.

Also, could I ask you perhaps to reset your attitude a little? Instead of trying to start a war every time I post, please comment with a little more maturity.

Thanks.

[wwest]

Originally Posted by Jonny H

^ A good start but a single picture isn't really sufficient to be 'done'. How about writing up a proper report? Install experience, traces, data, long term test results. 'It starts and runs every time' is not data.

On many occasions, you are quite scathing about other people's efforts and views. You ask them to 'prove it', and back it up with data. If you are going to serve up your solutions, by your own rules you must do the same. Make a positive contribution to this forum, start your own thread, instead of dragging others down.

Also, could I ask you perhaps to reset your attitude a little? Instead of trying to start a war every time I post, please comment with a little more maturity.

Thanks.

First, I'm a customer/user, not a marketeer.

Insofar as the use of an E & I transformer core as an upgrade from a simple high loss "I" core I refer you back to the linked document that you stated was one of your CDI+ design reference materials.

Do you not agree with your own "reference" material that an E & I core ignition "coil" will yield an additional 60% energy to the plug arc?

Plus, anyone with even basic electronic training/knowledge would immediately understand the advantages of a true transformer core vs a core with an open magnetic field path.

Same is true of the use of a "standard" ignition coil with a CDI system. The range of specifications for a coil to be used with a 12 volt Kettering system will be fairly tight, critical(***). But one of the advantages of the CDI system is that those specs, primary resistance and inductance are made a lot less critical.

Had you been a participant in the actual design detail of the CDI+ you would have a ready understanding of these facts. I would suggest that whoever that person(s) might be that you consult with them before posting statements/answers/responses here.

*** Note the change in coil design when Porsche switch from CDI back to Kettering with fixed dwell time.

[Jonny H]

Firstly, I am an electronics engineer, not a 'marketeer'. I am not trying to sell anything on this thread, I have not once mentioned our product on it.

I do agree that a transformer coil transfers more energy to the plug. I have never disputed this. It does not help the OP though does it?

I simply stated that changing the spec of the coil may cause it to work differently.

And please...

...anyone with even basic electronic training/knowledge...
Had you been a participant in the actual design...

False assumptions. Ask me straight up if you want to know.

[wwest]

Originally Posted by Jonny H

I can't give an absolute yes or no to the OPs question as I haven't personally tested an MSD coil.

The CDI box and coil, although separate parts, are part of the same circuit so they are matched at design time. If the coil is changed to a different type with different characteristics, this could result in excess heat being generated in either the coil or the box. In extreme cases, the CDI output circuitry could be destroyed.

This is why most aftermarket ignitions require that you also use their coils.

You need to compare the MSD and original Bosch coil specifications for primary resistance, inductance and number of turns. See whether they are in the same ballpark.

Still agree with this...???

Due to the higher efficiency of an E & I core ignition it would a lot less likely to fail due to internal heat build-up.

Agreed..?

Addresses OP's basic concerns.

[Jonny H]

Originally Posted by wwest

Still agree with this...???

Due to the higher efficiency of an E & I core ignition it would a lot less likely to fail due to internal heat build-up.

Agreed..?

Addresses OP's basic concerns.

Yes I still agree with my original statement.

Three problems I have with the TFI coil. Not the technology, but what is actually available:

1) I am in Europe and they are very hard to find here. There is really only one brand available and that has very poor reviews and high failure rates.

2) They are very cheaply made. Cheaply made transformers in other products we encounter are a usual failure point. As part of my day job I oversee CE marking which involves comprehensive testing and it is a sad state of affairs that many products fail basic testing. The COP packs in my modern car (Nissan engine) only last 15000 miles. That's pretty poor in my book. By contrast, the Porsche coil on my SC has done 130000 miles and is going strong.

3) They don't look standard. Personal preference.

I'm going to get a couple in to test. Will report back.

We are looking into making a high quality transformer coil in a standard looking casing.

[wwest]

Originally Posted by Jonny H

Yes I still agree with my original statement.

Three problems I have with the TFI coil. Not the technology, but what is actually available:

1) I am in Europe and they are very hard to find here. There is really only one brand available and that has very poor reviews and high failure rates.

Heard of the internet for global purchases..??

2) They are very cheaply made.

"Painting" with a very broad brush again...?

Cheaply made transformers in other products we encounter are a usual failure point.

There's that broad brush again! What % of products you have evaluated fail due to cheaply made transformers vs other causes.?

As part of my day job I oversee CE marking which involves comprehensive testing and it is a sad state of affairs that many products fail basic testing.

The only challenging test we had to pass for CE rating was EMI/RFI...

The COP packs in my modern car (Nissan engine) only last 15000 miles.

TURBO(??)"(Nissan engine)"...??

Are you sure the COP failures aren't the result of external factors..??

Ford F150 EcoBoost....

Ecoboost condensate drain hole, post your results here - Ford F150 Forum - Community of Ford Truck Fans

That's pretty poor in my book. By contrast, the Porsche coil on my SC has done 130000 miles and is going strong.

Your Porsche coil is oil filled, no carbon tracking due to multiple flashovers.

3) They don't look standard. Personal preference.

The 78's OEM coil is stored in the car.

I'm going to get a couple in to test. Will report back.

We are looking into making a high quality transformer coil in a standard looking casing.

https://www.cwsbytemark.com/index.php?main_page=index&cPath=206_231

[wwest]

We used this type back when designing PWM switching power supplies.

Stack of 4 inside a standard coil case..?



https://www.cwsbytemark.com/index.php?main_page=index&cPath=206_231

Toroid Ferrite transformer cores can be more efficient, but manufacturing is more costly.

[Jonny H]

^. Thanks

Cars are very cheap today, compared to 30 years ago. The only way the auto industry can make money is by cost reducing every part. Every year, parts suppliers are asked to make the part cheaper than before. I know this to be true since I have worked closely with people in the industry in my day job.

This not only makes the cars cheaper but also enables additional revenue through servicing and the sale of spares. Although technology has progressed, tolerances and safety margins have been squeezed to save cost. We have got used to everything being cheap and disposable.

Google 'coil pack lifespan' and you'll find thousands of hits across all vehicle brands with reports of failures, typically every 30000 miles. My modern car (actually a small van) is a 4 cylinder 1.6 petrol non turbo. It has done 60000 miles total and has been through 6 coil packs, an alternator, a catalytic converter, plus it has a baffling occasional gearbox 'multiplexer' error and a pressure release valve that keeps venting even though no fault can be found.

'wall wart' power adapters are amongst the worst offenders. An independent EMC lab recently tested 5 adapters for us that bore the CE mark. Only one actually passed. All the others failed on radiated emissions. Two of them physically exploded on the 8kV test. I've seen 220V mains get on a USB cable too. One of the failed adapters was a lovely shiny white one, I'll leave the fruity brand name to your imagination.

I may paint a broad picture, but often it really is a case of 'they don't make 'em like they used to'. The 911 is the perfect example of that statement. Well made, long lasting, durable.

It really is a race to the bottom if we keep buying crappy cheap goods. Proper craftsmanship is being lost, wages are pushed down, small firms going out of business, skills are being eroded. It is horrible seeing this happen.

[wwest]

I currently have 2 cars up for sale:

A 1992 full-spec LS400, purchased new, now with 160,000 miles, currently in need of PS pump and a thermostat. NEVER in the shop, DIY oil changes, etc.

1995 LS400, purchased with 30,000 miles, now pushing 300K. Shop time was 2 timing belts, otherwise DIY oil changes, etc.

Otherwise:

2001 AWD RX300, purchased new, now 110,000 miles, NO shop time, DIY...

2001 911/996 C4, factory delivery, 30,000 miles, no shop time.

1988 911 Carrera... 97,000 miles, (Damn DME relay).

Prior to 1985 I was pleased with <100,000 on my vehicles.

First generation Prius (don't remember MY), 73,000 miles, NO shop time

Friends with Fords/Toyotas seem to be having the same level of luck as I.

1978 Porsche Targa... 109,000 miles, Rubber clutch replaced at 47,000 miles

1993 Ford Ranger, 2.3L, stick, rebuilt tranny at 130,000 miles.

[rick-l]

Bet that was a pretty big supply using vacuum tubes

Originally Posted by wwest

We used this type back when designing PWM switching power supplies.

[rick-l]

Originally Posted by wwest

the not unsubstantial energy left in the magnetic field post plug firing will be returned to the "charge" capacitor.

"I" core: That 60% energy level loss due to magnetic field "leakage" will be dissipated as HEAT with in the coil structure.

Could you back either of these statements up with some science?

[wwest]

In both cases the not unsubstantial energy left in the magnetic field post plug firing will be returned to the "charge" capacitor.

(page 43, "-100")

"I" core: That 60% energy level loss due to magnetic field "leakage" will be dissipated as HEAT with in the coil structure.

(Page 48)

http://www.worldphaco.net/uploads/CAPACITIVE_DISCHARGE_IGNITION_vs_MAGNETIC_DISCHARG E_IGNITION..pdf

[wwest]

More "science".

Air gapped magnetic cores

[rick-l]

Originally Posted by wwest

In both cases the not unsubstantial energy left in the magnetic field post plug firing will be returned to the "charge" capacitor.

(page 43, "-100")

"I" core: That 60% energy level loss due to magnetic field "leakage" will be dissipated as HEAT with in the coil structure.

(Page 48)

http://www.worldphaco.net/uploads/CAPACITIVE_DISCHARGE_IGNITION_vs_MAGNETIC_DISCHARG E_IGNITION..pdf

That would be great if any of the systems discussed here had a Royer oscillator. All the systems discussed here have a flyback. The energy is returned to the battery.

Where are the 60% losses due to eddy currents you discuss?

[rick-l]

Originally Posted by wwest

More "science".

Air gapped magnetic cores

That "I" core has a pretty big air gap