CDI changed to CLASSIC RETROFIT CDI+
 

Just finished installing my newly purchased, from PELICAN PARTS, Classic Retrofit CDI+.
My original CDI was working fine but after trying to find a correct rev limiting rotor for my 1979 911 SC (ROW) that I Autocross all summer long ( and I really need the rev limit protection!) decided to go this upgrade route.
The benefits of the CDI+ should help to bring my ignition into the 21st century and reduce my worries of the 40 year old unit failing or losing performance.

The installation was very easy and the instructions are detailed and easy to follow. I just did the plug and play option and did not do any software mapping. I did adjust and calibrate my tach and set the hard and soft rev limit to my desired numbers.

The car started right up and runs great. I will have the AFR adjusted to reap some additional power as suggested in the instructions.

Did additional replacing of a new “black CDI coil”, new Beru shielded wires, and new spark plugs as was suggested by CLASSIC RETROFIT.

Anyone hesitant about the cost should know this is a high quality product with 21st century engineering with substantial benefits as compared to buying a original CDI box.

Sweet! I ordered the last one Pelican had in stock. Should be here tomorrow.

I’m also searching for the elusive black coil although Jonny responded to my PM saying the silver Bosch has the same specs just not the reliability of the original.

I plan to switch from CIS to carbs in the not too distant future so the cost of the CDI+ vs having my existing distributor recurved wasn’t all that much. Having the advantage of the multi spark in the meantime is a plus.

I had bad experience with Bosch silver coils. I have barn find 76S with 3.0 liter PO haphazardly installed, had things together with bailing wire. Replaced silver Bosch coils three times before discovering on this forum that they’re no good. I only put 200-400 miles on the coil each time and left me stranded. I thought it was engine related and discovered the silver coils can’t withstand the engine heat. Buy the MSD coils and remove the sticker. Don’t buy Bosch silver coils unless you like riding in tow trucks.

I’ve read plenty of accounts just like yours about the silver coil. The one I have has been in the car since I bought it ~4yrs ago. Unfortunately until I can find a black one it’s what I’ve got to work with. The MSD is a no-go unfortunately. Below is info I received from Jonny H in a PM.

Finally got a chance to install the CDI+ after checking the timing and making a small adjustment I swapped my rebuilt and by all accounts perfectly functional Bosch unit for the CDI+. Checked timing again, it was bang on so I took it for a quick spin in the neighborhood.

I don’t know if it’s a placebo effect or what but it seems WAY smoother at low RPM and low speeds. It was always a little jerky in 1st gear parking lot situations and I just chalked it up to the nature i
of the car, but it’s completely gone now.

I’m excited to see how it fairs on a longer test drive and to delve into some of the more advanced features.

yes, that was also my experience and many others with me. Much smoother low rpm running.

^ Combustion analyser says better burn, dyno says more power. Around 800 cars running CDI+ now. That’s enough of a sample size to quash any notion of placebo. To think I had to fight it out with some on here a while back - so over that now!

We’re currently testing on historic F1 Cosworth DFV V8 at 10000 RPM.

I got about 80miles in today. Definitely smoother, car ran great the whole time. Next step is to map out the timing and order the distributor lock.

What is the official Classic Retrofit recommendation for an ignition coil when used with a CDI+? I have a "replica" black coil purchased from another vendor..... thoughts on that? It does look like the one you used to sell but no idea what the internal specs might be.

^. Yes we used to sell a replica coil but we had failure issues and also with the orange plastic being too brittle. This led to cracking around the terminals and the ‘nose’ of the coil.

It is a shame because the specification and performance of that coil matched the Bosch unit pretty well.

Essentially, a large proportion of canister style coils are made in China to a price. That includes all the common US brands.

We are now working to produce a high quality canister coil in the U.K. having found a partner with the proper old school winding equipment. Everything including the wire will be quality focussed. It will take us a few months to get going.

I guess I'll be careful with mine then..... at least for a few months! Should have the 3.2SS with the MFI fired up sometime soon.

(EDIT - PS - Thanks for the reply! - And for continuing your efforts!!)

I feel my foot approaching the slippery slope.

I've been looking at 123 Ignition and it seems like the 123 ignition + the Classic Retrofit CDI might be a good marriage.

Do you think there's benefit to be had from this combination to (self) justify the $1,500 investment?

Not sure that combination is compatible, or necessary. IMO the CDI+ is the easiest/best choice over the 123ignition. Lock your distributor advance and use the CDI+ to control the curve, rev limits, etc.

It depends on the condition of the old distributor. One one of my other vintage cars experienced low RPM running issues that were never solved until switching to the 1-2-3 Ignition distributor. Even after tests said it was "within spec" the 50+ year old distributor was just not working as it should. Things wear out eventually.

In a 911 with a good distributor Classic Retrofit CDI may be all you need. That said, I can see certain scenarios on older 911's where the 1-2-3 Ignition distributor + Classic Retrofit CDI might be a very good combination.

Most can achieve the same results by just increasing the timing 3-5 degrees over stock!

A 13mm wrench isn’t going to give you the same results.

I installed a 123ignition. At first the performance was great. In then started to deteriorate. I notice the advance exceeded to config. I took it apart and saw evidence of arcing on the leading edge of the rotor and cap. I contacted 123 they were no help at all. The US distributer defaulted to the overly simple manual and wouldn’t contact 123 in Holland on my behalf. I restored my Bosch distributor and reinstalled it. The car runs again.

If you throw a rock at a pack of dogs, the guilty one barks every time! :D

Interesting, because it's been my experience that with a good CDI you can generally increase power by retarding the timing a few degrees over stock. And it's because the initial flame kernel is larger so combustion proceeds at a faster rate initially. That's with standard to lean mixtures. Overly rich and one would likely need to advance the timing over stock regardless of the ignition system, but less with a decent CDI. Fred

Please explain.

You are aware of performance "tuning", right? Well, for a stock engine with the AFRs set properly, advancing the timing is all that's done.
Just some very basic knowledge, a PC, and a tuning app is all that's necessary. A HS auto shop student is more than capable of "tuning".
Some have indicated that for every degree of timing increase, about four ft-lbs of torque results.

The much more effective approach for the early 911s with the offset spark plug, was to twin plug each cylinder.
This results in having a higher CR engine without significantly reducing the timing to reduce the likelihood of detonation.
The later Porsche engines with the spark plug in the center have much higher CRs. As of the 996, Porsche no longer
found a benefit of using a CDI vs an inductive discharge ignition IDI. With present day semiconductor technology,
i.e. switching speeds & current capabilities, an IDI can produce a spark equal to any CDI system.

I put a CDI+ on back in 2017 along with plug wires, a coil and a rebuilt distributor (vacuum advance delete). Three years of nearly year round daily driver duty and 35k miles later it hasn't given me the slightest concern or hiccup.

Many original 3 pin Bosch CDIs from the early 1970s are still running their original 911.

I'm better than a HS auto shop student, but darned if I can't figure out where to plug that PC into my SC! Help me out here, Swami.

Inductive and CDI will never be equal. The phase angle between current and voltage is much different between both types and this fundamentally changes the spark characteristics. Furthermore, voltage is self regulating with an inductive ignition while with CDI it needs to be controlled at the source. There are other distinct differences too. No, the sparks are not equal. Fred

love it! L/D is just waiting in the weeds to strike and tell you 50 year old electronics are fine and can't be improved upon.

My original 3 pin Bosch is in a box properly labeled and sealed as a precious relic in the 911 parts cabinet.

I have been running an excellent CDI unit, not a MSD or the one discussed here. Been in use for 12 years and over 100,000 miles on my 2.7 MFI WITH DRAMATIC IMPROVEMENT over OEM.

I am sure Jonnies system is great too, but it was not an option when I did my research made the installation.

Right, the inductive discharge ignition is the de facto automotive OEM ignition for all present day vehicles,
e.g. Porsche, BMW, Mercedes, & Ferrari, and even in racing (F1).

https://books.google.com/books?id=TzqIDQAAQBAJ&pg=PA215&lpg=PA215&dq=Formul a+1+inductive+ignition+system&source=bl&ots=D-zZuAcGsY&sig=ACfU3U3iXm-hE92bIWHetd_lWfqc5Kti4w&hl=en&sa=X&ved=2ahUKEwi4vu mf1fTnAhXxJDQIHRYeAFUQ6AEwDHoECAoQAQ#v=onepage&q=F ormula%201%20inductive%20ignition%20system&f=false



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The typical CDI spark duration is 50-150us (Bosch-80us, MSD-40us), which results in a marginal spark as noted in the reference.

Agreed, A good CDI has an effective duration of at least 350µS. Fred

Just advancing the timing is missing a couple of the biggest selling points of the CDI+. The multi spark to 10,000rpm and the ability to customize the advance curve. I’m switching from CIS to carbs on my 82, to take advantage either I need to send out my distributor for a recurve or install the CDI+ and achieve the same results.

The only way you are using a PC to “tune” a 1982 911 is by going to EFI or using the CDI+

It's just been shown that a multiple spark system has no benefit.
You have an engine capable of 10K RPM?

Customizing the advance curve will provide a margin gain over just tweaking the timing.

‘Dave’. Your technical ‘proof’ data appears to be for a modern Ferrari F1 engine. I would imagine that the piston, head, inlet and fuel system and pretty much everything else is a million miles away from an air cooled Porsche.

Btw, McLaren use both CDI and inductive ignition. You cannot say that one is better than the other in all cases. It depends on the engine design.

https://www.mclaren.com/applied/products/download_support_document/

I think it needs to be stated that Jonny's CDI has the multiple sparks close enough together to effectively give a long duration spark. This is different than MSD where the sparks are quite short (40-50µS) followed by a full 1mS without any spark before the next in the series comes along. Obviously, 1mS is far too long an interval between sparks except perhaps at idle rpm. Fred
EDIT: It should also be noted that the multisparking that was tested in the article was done with an inductive ignition, not CDI so the peak power of each spark would be much, much lower than Jonny's CDI.

Need help / advice with CDI+
 

Really love the CDI+ on my '78 930. I do wish they would add support for turbo boost signal as that would allow elimination of the boost retard function on the distributor... but I have a more pressing matter at the moment. Please advise / help if you can. I am upgrading my intercooler, adjusting valves and installing new ignition wires so the car is in pieces at the moment. I read a note in the Classic Retrofit version notes for the 1.38 version (the latest) which said that there was a bug introduced in the firmware in an earlier version by the increase of the clock rate on the CDI+ processor which can cause the box to shut down in high heat circumstances (ugh) so I planned to upgrade the firmware while I have easy access to the CDI+ box. I downloaded the 1.38 version of the software, plugged in the USB wire to the laptop and was able to communicate with the cable. I re-installed the supplied drivers to make sure I had that right. I get to the point where is says 'Connect to CDI' so I plug the USB wire into the back of the CDI+ (black wire to the bottom of the unit) then I turn on the ignition switch and nothing happens - no connection to the box. The software sits at that point and no connection with the box is made. Is it possible that with several ignition components removed from the car (coil for example) that the CDI+ will not communicate? I have tried it several times in slightly different sequence to see if it was an 'order of connecting' issue but no luck... I'm concerned now that my ignition box may be bad and I will be dead in the water after the upgrades are done. Anyone have this trouble with this version and this scenario? Does the car need to be running to connect to the box and upgrade the firmware?

Remember, there are multiple sources for very reliably rebuilt Bosch CDI units which typically last over 30 years. Pelican Parts has some!

The CDI+ boxes are ‘unbrickable’ so don’t worry about that.

You should be able to do the update on the bench with a 12V supply substituted for ‘ignition’ and the USB lead.

Shoot us an email if you still have trouble.

So, with the CDI one needs a conventional old style coil and solid copper wires? Spiral wound Clewett's need not apply?

Our CDI+ boxes are designed to be compatible with the original coil and spark plug leads. We have found most aftermarket coils too slow for our rapid multispark. You can make other coils work with CDI+ by increasing the spark interval in the unit (using the software) but that defeats the object of having the fast spark delivery.

..got it on the coils.... now, will spiral wound Clewitt style wires work as well as the stock solid cores?

Read post #28 & #29. The second spark is too short to have any real effect, and has no effect with most standard coils.