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

My car has been known to suddenly die after a long run on the road and I thought it might be fuel related. Lately though someone suggested that the MSD Blaster ignition coil I installed might be overheating and causing the shutdown after a nice run with the car. The questions came up as to whether I was using a non-resistor rotor? does the Blaster has an internal resistor? or I have external ballast resistor?

I do use the 6500 rpm cut off rotor, which I just realized is not the "non resistor rotor". I will switch to the non resistor rotor, but can anyone shed any light on what's going on with this system set up. And yes, I have bought the silver made in Brazil coil, which failed me miserably after purchase.

thanks

Bob
1973.5T

Bob,

I was searching for the same issue a few years back. I don't remember where I found it in this Forum, but there is a post from either Warren Hall or Grady Clay regarding the MSD master blaster coil. From the testing that he did, he determined that the coil was the exact same spec as the original factory coil.

Not sure if that answers the question but hopefully can point you in the right direction.

Matthew

dont know about your question. but during the build of my 951 DE/street car I installed a MSD blaster coil. it died on the first drive within minutes. replaced with another MSD and it died after a few months.

put the original coil back in for now, until I decide if I am going to go a full MDS / AL6

good luck.

Best...


Accel 140008 E Core Electronic Super Coil 42K Volts | eBay

I wouldn't go near an e-core coil the specs are absolutely wrong.

Here is my compilation of coil data:

A lucky eBay find: NOS SWB Coil

Appreciate the data.

Bob
73.5T

Best.....
102002 Daytona Sensors Ignition Coil CD 1 System | eBay

Better.....
ProFire

PFC-M75, CD Ignition I ran one of these for years with Bosch CDI and it was great. I still have it if anyone is interested in purchase. Switched to Daytona CD1 coil that came with kit.

http://forums.pelicanparts.com/uploa...1452110786.gif
This is the NOLOGY COIL. The bracket fits right on the studs on the fan mount.

A picture says a thousand words...
 

Lets see how they look mounted...

I care how they work. E coils have been great for me. the Nology coil was great with the stock ignition, the other Daytona coil matches my CDI and has been flawless.

John Walker would know. When I did the MSD and MS coil, we had to change the rotor.....He picked up a common one at a local FLAP store....I thought still had the box with the part number, but no cigar....

dicklague

Sent you a pm
Ernie 81sc

Which specs?

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.

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

"..excess heat...."

How, where...?? The primary components affecting the coil, or being effected by the coil, are reactive, very low circuit resistance to dissipate energy as heat. Plus moving from ANY "I" core coil to an "E & I" would obviously reduce spark energy loss substantially

"..aftermarket... ignitions require..."

Read: COILS

http://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Products/Ignitions/6420_instructions.pdf

http://static.summitracing.com/global/images/instructions/sum-850610.pdf

^ Ok, feel free to stuff any old coil in there then. It doesn't matter what the designer of the circuit intended the CDI circuit to drive. A few turns of wire round an old shoe will do and is cheap and easy to make. Wire coat hangers make great ignition leads as well and you can insulate them with tape and chewing gum.

Remember, Porsche really didn't know what they were doing when they designed this stuff. It can all be replaced with homemade equipment or shoddy crap made in China and it will be absolutely fine! Trust me, I read it on the Internet!

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

Neither of the 2 installation guides I linked suggested taking the issue to such great extremes.

Having trouble eating crow..??

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.

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.

My '78 911 Targa..

Data: It starts and runs well every time.

http://forums.pelicanparts.com/uploa...1452299714.jpg

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

Done. OUT.

^ 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.

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...

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

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.

SmileWavy

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

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

Stack of 4 inside a standard coil case..?

http://forums.pelicanparts.com/uploa...1452376833.jpg

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.

^. 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.

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.

Bet that was a pretty big supply using vacuum tubes

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

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

More "science".

Air gapped magnetic cores

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?

That "I" core has a pretty big air gap