MassGuy

I replaced mine over the winter. I think one is bad again. My car has the usual runs fine for awhile then its starts to miss and run like crap. I suspect the coil is overheating.

I have heard it rumored that the new Bosch stock is not so good. Now I believe I can varify it.

What do you suggest? What have you done?

Thanks!

Geoffrey

You can use any good inductive coil. Do not use a CDI coil or you will burn out the coil.

Lorenfb

"Do not use a CDI coil or you will burn out the coil."

Actually the ignition module will fail first.

MassGuy

Is there a specific brand?

I never want to deal with this issue again. Its a real PIA and it makes my car real sick.

Thanks!

MisterRisky

MSD Blaster?

They should work and you can get them here for under $50 USD. Although I am not sure that the one linked to here at J and J is right for our cars. Anyone know which one to use?

Indycam

I would not put on any coil other than the one made by bosch .
Try to find a good new or used non brazilian .

MisterRisky

Why not, Indy? I'm not arguing, just curious.

MassGuy

Well I wish you luck with these Bosch coils because I think they suck. Brazilian or not they should be reliable.

Indycam

Because I am not knowing what all the little specs on the coil mean .
The engineers who speced out the ignition system did so with knowledge that I will never have .

MisterRisky

Fair enough.

Geoffrey

I think you need to really look at the specifications of Inductive Coils which STORE and step up energy vs CDI coils which simply step up energy. Most Inductive coils are very similar and I would have no issue with installing an MSD type Inductive coil in the Porsche. The ignitor will limit the current of the coil and the coil windings simply affect the charge time of the coil.

Lorenfb

"Most Inductive coils are very similar"

Not correct. The series resistance AND the inductance both can vary.

"I would have no issue with installing an MSD type Inductive coil in the Porsche."

The MSD type of coil is a CDI type of coil which DOES NOT store the energy
which is required in an inductive system. Its inductance is TOO low as is its
series resistance.

"The ignitor will limit the current of the coil and the coil windings simply affect the charge time of the coil."

Even though some ignition modules have current limiting capabilities, they can fail
when used with the wrong coil, e.g. CDI types. The key is not only the current limit but
the module's power handling capabilities.

"Inductive Coils which STORE and step up energy vs CDI coils which simply step up energy."

Neither ignition system "steps-up" (creates) energy, i.e. a basic law of physics.
The CDI coils just transfer the energy stored in a capacitor. Both CDI & IDI
systems step-up the primary voltage as was the case for the old points ignition
system used prior to the use of electronics.

The Bosch silver coils are not reliable. The Bosch black coils (original OEM) are
fairly reliable. The Bosch blue coils are quite reliable. Again, these are all inductive
type coils. The exception is the small black coil used in the early 911 CDI ignition.

Remember, an inductive type coil can always be used with a CDI system, but not
conversely.

elbeee964

Oh -- wonderful. [resigned sarcasm]
Care to guess which I'm packin'?

Duck

Any body know the part number for the blue coil that will work on a 964?

dutchcrunch

hello mass guy, sounds to me like you have high resistance down steam of the coil that keeps going out, lets say its the coil that operates the upper plugs, either you have have a bad cap or bad wires that when you put a new coil on its fires for a while but has to work to hard and overheats and fails.

when was the las time you replaced the wires?

i posted a while back about the caps having a coatig on the pins that could be your problem. this happen to me and resulting in a bad wire.



Loren, i have a question for you, the 993 have the same distributor as the 964, can we use the 993 coils on our car, i seen them for cheap. and maybe these coils do not come from brazil???