Jonny, I am really impressed by your parts and I am grateful that people still go the effort to develop new parts for our old cars.
I own an 1983 930 Turbo with lots of upgraded parts (headers, 964 cams, gt35, bigger IC but still on CIS and I want to keep it that way). I currently run an MSD 6al2 with a boost retard function, which I like to have on a turbo. Is it in your plans to ad this function to your programmable CDI?

Also, this in recently.

3.0L SC, high comp pistions and custom cams. Still on CIS. 240 BHP.

http://www.classicretrofit.com/media...png?width=1024

http://www.classicretrofit.com/media...png?width=1024

And this:

Standard US Spec 180HP SC motor. NO INTERNAL CHANGES. Not even rebuilt.

PMO 40s, SSIs, CDI+. 232 BHP.

http://www.classicretrofit.com/media...jpg?width=1024

If the boost retard input is just a 12V signal then we could do that already with a very minor firmware update. Can you confirm?

Johnny, you've probably done this but a question....have you run a baseline with your CDI of a completely stock 911 SC ....when you show HP increases with Carbs, SSI's etc. how does one know what is making how much HP?
The picture shows a motor dyno so this is not rear wheel hp?

Yes, of course. Standard SC vs same car with CDI+ and my car with cams:

http://www.classicretrofit.com/media...jpg?width=1024

Difference between orange and green traces for same car, same igntion timing (no changes to map). It doesn't look a lot but it's the mid range that makes the car feel faster, not the headline power.

There is also the independent test report on our website.

Engine builders using CDI+ have no interest in going back to a Bosch unit every time they build an engine. These guys are already 'sold' on the unit through many hours of testing.

The CIS engine was dynoed on a standard Bosch box at 230 HP and there was a substantial dip in power at 4500 RPM that CDI+ improved with igntion mapping. The dyno shown is ex WRC so I'm fairly certain is showing corrected HP at the wheels.

A PMO'ed standard 3.0L SC engine with SSIs would normally make around 210 - 220 HP. Interestingly, this engine responded massively to the double spark but mapping made only minor improvements.

To be honest, we are well past having to 'fight it out' with the doubters. The units are used by some of the best engine builders and race teams out there.

Not challenging you Johhny but had not seen this chart. Thanks.

The key problem is to reliably discriminate been noise and a true knock signal characteristic
of that particular motor. Once that's known, the balance of the processing is relatively simple.

On the 964 DME the “knock MCU” is a Motorola 68705R3 clocked at 4MHz. The main MCU sends an analog signal via a 3bit DAC to one of its analog inputs and can read two bits back mapped to an I/O address of the main MCU. The Motorola gets resets for every ignition event. I pulled the code off it but haven’t gone through it. Stuff for a rainy day....

Lets see what develops. Ive been very happy with what Jonny has developed so far. A little bit of modern technology for our older cars.

Having just now collected my 72E from having it’s dead CDI box replaced by one of Jonny’s units I thought I’d share a qualitative (not quantitative) quick review..

It certainly immediately noticeable in terms of cold start and idle stability with the hand throttle..... much much steadier and yet better response. Makes those first few miles a better drive.

Once warm the overall response is crisper and feels sharper. At steady speeds I felt an ever so slight tremor at certain speed, probably to do with the slowly failing CDI box... now it feels very steady yet quick to react to the accelerator. Sona idea if the amount of power has changed, there is already enough for my driving, however it feels more accessible now.

Admittedly I have forgotten the fine detail of how it was 20 years ago when I first drove it so perhaps the CDI was as good once, but for me it has made the overall drive even better and more fun....

Software release 1.33
==============

Main new feature is a 10k tacho. Some refinements to operation too.

http://www.classicretrofit.com/media....png?width=800

Software update available on either product page, e.g. this one:

Classic Retrofit CDI Plus upgrade ignition unit for Porsche 911 models 3-pin

CDI+ units available right here on Pelican.

P/N 911-CDI-3P or 911-CDI-6PN

Any chance of a Mac compatible software?

I'm with you.

I actually run a Mac myself and use the software through Parallels.

Maintaining two code bases is a bit of a nightmare so unless Flutter (or similar) moves to desktop it would be a big undertaking. It may be possible to port it to java or HTML5 but a ton of work and retest required.

Defective CDI+
 

Jonny,
I was thinking about purchasing a CDI+ box but heard from a guy at a car meet this weekend that some recently have been defective. Has this problem been fixed?

Yes fixed. Not defective, just over sensitive.

We recalled around 20 units as a precaution because we found that their over temp protection was being over cautious. It looks like two diodes that have been in the design from day one have changed their specification.

All customers were personally contacted and units are being corrected.

In more exciting news, my favourite car at the moment (not mine) is this little 69S road legal race car. It had an engine rebuild in 2014 and was dyno’ed back then. Unfortunately for the owner it had to be stripped due to an oil feed issue. It was rebuilt again to standard S spec and slightly different cam timing. MFI tweaks and some CDI+ tuning has seen 15 - 20 ft lbs torque increase across the board:

DDK - Die Deutschen Klassiker • View topic - 69S RHD

Jonny, layman's question: Re the curves on the stock SC without then with CDI+... in the most basic terms, does all that extra torque at lower RPMs come from CDI+ optimizing the timing (over what the distributor can do itself) or by sending more voltage to each plug? Or both, neither, or something else? Ignition theory isn't my strong suit. Thanks, John

^ It’s all about converting the energy in the fuel mixture to kinetic energy to move the piston. The more energy you put into the spark, the quicker the flame front and the energy release meaning more power. It also means that you can get more power with less advance (same as with twin plugging)

You can increase the spark energy by increasing the voltage at the detriment of the ignition components. We choose to stick with the stock 300v but take advantage of the very fast Bosch black coil and fire the spark twice in quick succession. This guarantees double the spark energy but does not damage the coil or rotor and there is no neeed for ‘special’ leads.

If the ignition is more efficient then it follows that the fuel mixture may be adjusted to take advantage of the increased spark energy. My SC responded to enrichment after fitting CDI+

We generally find that the engines also respond further to timing adjustments when dyno’ed but most of the major gains are through spark energy.