Coils for CD+ ignition

[morini]

I am planning to upgrade the ignition on my 1977 911S (2.7 CIS with SSI+Dansk and a Permatune from ´98) and my 1971 911T (2.2 slightly tuned). The 1971 runs very strong, but Classic Retrofit claims that these old engines benefit the most from CD+. The 1977 stutters on low revs and since I refurbished the CIS last year, I am now going over the ignition to see if the culprit is here.

According to internet wisdom and Classic Retrofit I will need black Bosch coil to get full advantage of the CD+ ignition. Both my coils are black and are stamped 0221 121 001, see attached photos, so I might be in luck. Or they could be painted silver coils. Can any of you see from the pictures if these are the real black coils?

Any advice on other ignition upgrades based on the attached photos are highly appreciated.

1971:

1977:


Snowy regards from Norway!

[Flojo]

Best coil is probably the MSD 8222 HV (epoxy filled, Offroad purpose)
It runs strong in my 3.0 SC with a silver Permatune

it has a factory black housing. so when you strip the MSD-sticker and add a Bosch sticker, it looks quite OEM (despite the fact the coil housing is longer than the factory black coil).

[Ian Comerford]

Jonny will advise that the MSD could cannot provide the required spark above ca4500rpm. He told me to use the standard black coil for the SC

[mysocal911]

Originally Posted by morini

I am planning to upgrade the ignition on my 1977 911S (2.7 CIS with SSI+Dansk and a Permatune from ´98) and my 1971 911T (2.2 slightly tuned). The 1971 runs very strong, but Classic Retrofit claims that these old engines benefit the most from CD+. The 1977 stutters on low revs and since I refurbished the CIS last year, I am now going over the ignition to see if the culprit is here.

According to internet wisdom and Classic Retrofit I will need black Bosch coil to get full advantage of the CD+ ignition. Both my coils are black and are stamped 0221 121 001, see attached photos, so I might be in luck. Or they could be painted silver coils. Can any of you see from the pictures if these are the real black coils?

Any advice on other ignition upgrades based on the attached photos are highly appreciated.

Right, claims! Lots of money wasted over the years for performance products claims.
Using a 13mm wrench to slightly advance the timing results in performance gains too.

[QueWhy]

The silver coil will provided the multi spark just like the black coil. The issue is with the reliability of the silver coil vs the original black.

Originally Posted by mysocal911

Right, claims! Lots of money wasted over the years for performance products claims.
Using a 13mm wrench to slightly advance the timing results in performance gains too.

They have data and dyno sheets to back up their claims. Anecdotally my car was noticeably smother in the lower rev range with the CDI+, the CDI+ also has some other tricks up it’s sleeve not offered by physically advancing the timing.

[mysocal911]

Originally Posted by QueWhy

They have data and dyno sheets to back up their claims.

Have you personally confirmed "data and dyno sheets"?

Originally Posted by QueWhy

Anecdotally my car was noticeably smother in the lower rev range with the CDI+,

Right, anecdotally!

Originally Posted by QueWhy

the CDI+ also has some other tricks up it’s sleeve not offered by physically advancing the timing.

Like what "tricks"?

[Jonny042]

Love my CDI+. Fires through the mega-rich mixtures of my MFI system with ease. Parts klassik makes a coil that's been working fine for me with the CDI+.

Oh and save yourself a bunch of hassle with plug wires and get Clewett wires.

[Flojo]

Originally Posted by Ian Comerford

Jonny will advise that the MSD could cannot provide the required spark above ca4500rpm. He told me to use the standard black coil for the SC

what? first time I hear this.
we're talking about the HV 8222

edit, even the 964 and 951 guys use them in their TCI system.

good read: http://www.roguetuning.com/944951_ignition

quote:
Since this coil charges faster, even at the short charge-time of 6500rpm, it has more current flow than the Bosch coil.
We see it has ~7.5amps of current, which means this coil is only down to ~70% of its peak possible energy -
a HUGE improvement over the factory Bosch coil (which was down to ~34% energy at the same RPM).

For DME users: What needs to be done (to catch loss of ignition-energy at high RPM) is to change the charge-time data in the DME software (easy for us to do, and is user-available in the DME Tuner software).

no worries to plug-and-play for Bosch K-Jetronic systems

[Ian Comerford]

Yes, the 8222. I had a full engine rebuild last month and the garage fitted an 8222 I have carried in the car as a spare for years. Being new it looked far better with the refurbished engine detail than the original, slightly tatty coil. Jonny saw one of the pictures on Impact Bumpers and mentioned that contrary to its name the coil cannot provide the required level of spark above 4500rpm for the CDI+. Jonny knows his stuff so I’ve swapped it out for the old one, but repainted it.

[Jonny H]

To answer the OP's question, those look like original Bosch black coils so you are good to go. FYI, we will be launching a hand made high quality coil in a few weeks so keep an eye on our website and Instagram etc.

The issue with ALL common aftermarket CDI coils we have tested is that they are too slow to 'recover' for the multi spark output of our CDI+ system. The only ones we have tested that have similar characteristics to the Bosch coil are the coils used in the Lucas CDI on the Cosworth DFV F1 engine and the later Cosworth plastic coil.

Typically, after the spark event an MSD coil takes around 600-700us to 'ring out' and be ready to fire again. By comparison, a genuine Bosch Black (or silver) coil is fully ready to fire again within 200us. Both timing measurements taken in air, generally times are a bit longer under cylinder pressure.

[As an aside, the 'ringing' represents energy that has not been delivered to the spark plug. The Bosch coil has clearly been designed to match the other components in the ignition and reduce waste to a minimum.]

Our CDI+ system is shipped with a standard spark interval setting of 400us as it was designed to take advantage of the rapid firing/recovery characteristics of the Bosch coil. This allows us to deliver a meaningful second spark to further ignite unburnt pockets of mixture in the chamber.

MSD's spark interval is set to 1000us and they do not multi spark above 3400 RPM (for a 6 cylinder).

[Jonny H]

Originally Posted by Flojo

what? first time I hear this.
we're talking about the HV 8222

edit, even the 964 and 951 guys use them in their TCI system.

good read: Rogue Tuning - 944/951 Ignition System Testing

quote:
Since this coil charges faster, even at the short charge-time of 6500rpm, it has more current flow than the Bosch coil.
We see it has ~7.5amps of current, which means this coil is only down to ~70% of its peak possible energy -
a HUGE improvement over the factory Bosch coil (which was down to ~34% energy at the same RPM).

For DME users: What needs to be done (to catch loss of ignition-energy at high RPM) is to change the charge-time data in the DME software (easy for us to do, and is user-available in the DME Tuner software).

no worries to plug-and-play for Bosch K-Jetronic systems

Well, they most certainly are 'rogue', there are two immediate issues here:

1) They are testing the Bosch TCI black coil. This thread is about the Bosch CDI coil which is completely different.

2) Then they use an MSD CDI coil in an inductive system and claim it to be better. That is just wrong.

[morini]

Thank you for all input. Especially to Jonny H for the informative answer. While searching for information about your product I stumbled across a thread where you present your CD+. The patience and diplomatic skill you showed in that thread was truly impressive. Order on its way.

[Jonny042]

Originally Posted by morini

Thank you for all input. Especially to Jonny H for the informative answer. While searching for information about your product I stumbled across a thread where you present your CD+. The patience and diplomatic skill you showed in that thread was truly impressive. Order on its way.

+1 For Jonny and his patience and diplomacy. For some reason the trolls seem attracted to any post about the CDI+.

Welcome to the CDI+ club!

[mysocal911]

Originally Posted by Flojo

Best coil is probably the MSD 8222 HV (epoxy filled, Offroad purpose)
It runs strong in my 3.0 SC with a silver Permatune

it has a factory black housing. so when you strip the MSD-sticker and add a Bosch sticker, it looks quite OEM (despite the fact the coil housing is longer than the factory black coil).

The reason the MSD8222 coil functions great with all types of CDI ignitions with the exception of the CDI+,
is because the CDI+ spark pulse width is too short compared to other CDIs. Using an oscilloscope,
compare the wave forms as each CDI drives the 8222 coil to understand the problem.

[Jonny H]

Originally Posted by mysocal911

The reason the MSD8222 coil functions great with all types of CDI ignitions with the exception of the CDI+,
is because the CDI+ spark pulse width is too short compared to other CDIs. Using an oscilloscope,
compare the wave forms as each CDI drives the 8222 coil to understand the problem.

No, not correct. You *can* make the CDI+ work with the 8222 by increasing the spark interval to 800us in the software, but then you lose the advantage of having two spark events in quick succession.