I hate when discussions become a knowledge match. Well thought out products are not cheap!

Yes, all valid points.

We address all of those in our CDI+ design. Dare I call them improvements?

1. Overcharging alternator - 40%

CDI+ has over voltage protection.

2. Reverse battery jumping - 25%

CDI+ has reverse voltage protection.

3. Owner shorted the coil wire - 10%

CDI+ has short circuit protection.

4. Bad engine ground connection - 10%

CDI+ has a PCB ground plane attached to the case. In the event that the engine ground is missing, no damage is cause, just no spark.

5. Capacitor failure (engine heat Turbos) - 10%

CDI+ uses premium grade capacitors rated 600V. We only run at 300V.

6. Intermittent solder connections - 5%

CDI+ uses mostly surface components, machine glued and placed. No hook up wires or dangly components

I'll add a few more failures:

7. Input trigger failure.

CDI+ has opto-isolated input trigger for 3 pin points. Dedicated IC for the six pin VR.

8. Wire short to case. Not enough clearance between HV components.

CDI+ adheres to the high voltage directive which means all HV lines MUST have 3mm clearance to other components or chassis/case etc. The Bosch unit would not pass this directive today. On all units wires are run through gaps in the PCB against the side of the case, this is very poor design by today's standards. On the 6 pin units the pins themselves are very close together meaning there is a chance for HV to jump onto the other pins.



Porsche first used the CDI in 1969, that's 47 years ago - a long long time in electronics. Believe it or not things have moved on a bit since then!

Getting back to the original post, I think it all depends on your willingness to invest in your car, hence your question about do you want to own a valuable car is a good one. (IMHO, this is issue one of the things that has created the gap in current value of 911s at pre/post 1972-3, not just the bumpers. We just don't know what will happen to our electronics in another 20 years, but carbs will always be serviceable.) Personally, I would buy an MSD if my CDI were to fail today, but my SC has 100K miles on it.

The CDI+ seems like a really solid product, but at almost 4x the cost of an MSD I would hope that this product adds value to the car, now AND 20 years from now. My guess is that eventually one product will filter out as the best solution over the next few years or so. Of course, there will always be a few "investors" who will want to do anything to keep their cars original, and rebuilding their CDIs may pay off for them, if the rest of their car is pristine.

Does t have an ODBII port?

Outside looking in!!!
Got interested in the CDI's, helping fellow Montreal owners fix there units.
I fixed 10 so far and I replace many components in the units, since I got to take it apart and fix it anyway. The cost is ~60 dollars. Diodes, caps etc. All basic Components. Simplicity! Analog!

I have tested older units with No repairs and compared them to my refurbished units and the performance is much better , with the newer components. Can say that they would out perform an after market unit, but it's good enough for me.

Aside from that I believe there are much better units available today vs. the CDI. It' very easy to add a few enhancements to a circuit and make it better, but Engineering Hero's are a Dime a Dozen.

I've installed these units on 2 of my cars, and there performance has never been better. They start easier, run smoother, quicker on acceleration, and I get better millage. Even a buddy of mine put one on his Harley, he loves it!!

After market units are cool, but I'd rather stick to the CDI's. If the unit malfunctions on the road all I need to do is move 3 wires to convert to the original setup.

It came with the car so why not keep it in?? there are many vendors that rebuild them and I'm sure they follow my regimen to some degree.

OK, I'll take the bait here, (but only once!) ... I routinely repair these stock CDI units (hundreds a year) and by far the majority of the failures is the discharge capacitor ... over 80% of the units I repair have either a degraded, or totally open capacitor. The cap technology used at the time is prone to failure due to heat and displacement of the end-seals which results in decreased capacitance or open circuit situations. The next significant failure mode is due to reverse-battery events (accidental hookup of jumper cables incorrectly) and/or over-voltage situations caused by problems in the charging system. From time to time corrosion is also an issue in these units, depending on the environment they come from. Remarkably, the power components (flyback power transistor, SCR) and the smaller components that populate the PC-board seldom fail, with the exception being reverse-battery events. This is simply my observation.... yours may vary. ;)

This is a good discussion and could've been a better one. It is unfortunate that the exchange of ideas has to get catty. Some people freely share their immense knowledge and do so in ways that are helpful and positive. Others choose to act in unproductive ways and it's a shame.

Bosch rebuilds are an option for those that have them. The PO took the car I now own to a shop when his Bosch failed after 20+ years and 40-50k miles. Mechanic replaced with a PermaTune unit instead of having the Bosch rebuilt. Roughly 10 years later the PermaTune died. As these cars get older and transition through different owners, the odds of parts being replaced by non-OEM increases. MSD was a very cost-effective solution in my case and it sure seems to work better than the old PermaTune.

There will be a market for OEM rebuilds as long as there are people around with the knowledge/desire to do the business and customers who appreciate it.

There will also always be people who like to do different things like converting to EFI.

It's always nice to have options.

I totally agree. There is room in the market for all kinds of solutions including repair at all levels of budget.

What I don't understand is folks who moan about the standards of products, yet take exception in paying more for quality. This is a Porsche forum. The 911 cost more than a house when new. it costs more than a lot of houses today too!

Can you imagine the 911 salesman pointing out all the wonderful 'cheap stuff' it was adorned with? No, they did the opposite, they shouted 'this costs more because of the quality!’ from the rooftops.

We haven't finalise our warranty yet, but it is likely to be 3 years or more.

"...CDI+ uses premium grade capacitors rated at 600 volts...."

What I see is numerous standard commercial grade ELECTROLYTIC capacitors, likely rated at no more than 25 volts.

Have you done burn-in heat/cold cycling?

Electrolytic capacitors constitute the major failure cause of electronics system design of the complexity I see.

And why is that heat sink not in FULL contact, and bolted to the OEM case..??

http://forums.pelicanparts.com/uploa...1451939023.jpg

That one cap I can see in the pic has a high temperature range tolerance of 105 degrees CELCIUS while still maintaining less than 2.2 percent change in capacitance. That's a pretty stringent tolerance.
Mr West, you're being foolish. Come on, tell us why you don't want this product on the market? What's your beef? How did Jonny piss in your Cheerios?

Too much JUNK!!
wwest you made a mountain out of a mole hill.
I'm sure it's way more efficient than the STOCK Unit, but I believe it would not generate any noticeable improvement to the Original Design or the performance of any car just like these after market units. It's an illusion! Spent the MONEY of Course it's better!!

I'm a pure ANALOG engineer(TUBES RULE!!!), and your design looks impressive and very well engineered, but it's OVERKILL, for your just replacing a 300v one shot with something that can't be replaced or fixed.
The CDI isn't required to get a 911 running. I can bypass it in 10 minutes and get any 911 running.

The UNIT was used to reduce the stress on the POINTS(just acts as a switch with the CDI) and to provide a higher voltage to the primary of the coil to deliver a Hotter Spark from the Secondary.

BTW I put 800V caps in mine, cause it fit!! The Basic components in the original unit makes it very easy to upgrade and the modern components are better than the 40 year components I replace. My customers are very happy!

CDI boxes RULE!!!

+1

Right on!

Plus where do you go to get a broken one fixed...??

And we are off point again...


As stated in my first post, there are a lot of good options. And.... I noticed the new game in town that offered more features.

If a fully analog system can offer various rev limiting scheme. That would be pretty cool. Same with altering the advance curve. That would be a cool thing too. Is that available and priced well for the market?

As I posted the idea of fully interchangeable system with added features is pretty appealing.

I was essentially invited to this discussion by the OP mentioning our product. I really thought you'd be interested in knowing some of the shortfalls in the Bosch design. The shortfalls were actually listed not by me, but by Dave and confirmed by folks who fix original boxes. I then listed 8 de facto improvements over the original design in post #42. All of those are aimed at reliabilty.

That is before we even consider timing adjustment which is a well proven path to performance. If it weren't then MSD, Daytona, Canems, Motec, Megasquirt and of course ALL the major car manufacturers have got it wrong. All the guys who 'recurve' distributors would be out of a job too. I can't believe this is even being called into question on a car forum.

The boxes are subject to all kinds of testing, including cold/heat. We always prefer real world trials so we have a number of test mules out there. We have found issues this way and we resolve them. It is called constant improvement, it is what engineers do.

I am pleased to report that we have had no component failures in over 100,000 miles of testing.

wwest, as you don't know what that capacitor is doing in the circuit, how can you possibly make a judgement on whether it is fit for purpose? FYI, the 600V HV charge caps are on the other side of the board.

It's fun to watch the exchange of ideas here. Please let's keep it light and non-personal for as long as we can. This is the wonderful thing about capitalism and the free market -- we don't all have to agree on which product/design is better, we can vote with our dollars.

Don't like the CDI+? Don't buy it!

Really really don't like it? Bash it in the forum while the guy who sweated to create it is right there, if it makes you feel better! By all means, don't assume he's smart and ask him why he chose to do certain things, *assume* he's a scam artist and ridicule his decision-making :D

If you think its features outweigh its cost, pull out your wallet and vote to keep the project going!

Bosch engineers who created the CDI system would probably rethink one or two things if they had access to current design tools, machining, components, etc. is my guess. But who knows, maybe they really did create something that can't be improved upon!

P.s.

There is some confusion over analog and digital here. Seeing 'chips' doesn't automatically mean digital.

The majority of our board is effectively the modern equivalent of a 300V inverter and a switcher, both analog circuits. The VR and zero crossing circuit are also analog.

The only part of the design that is digital is the microcontroller that is actually the smallest chip on the board. It is the tiny square chip bottom centre, just to the right of the large via hole.

The same way that Griff (Kuehl a/c) did - wwest does not like new ideas or innovation that he did not think of first.

JonnyH

Interesting description. I'm not an EE but I see your point.

I was thinking of a 100% analog computer in my hypothetical full analog, rev limiting, plus variable timing, cdi box. Kind of like the early F-16 flight control system. :)

That's probably closer to the older msd boxes.

I've put our cards on the table, so here you go:

Daytona CD 1. OMG, they use the same capacitor as us, so must be junk then according to certain people ;)

http://www.4secondsflat.com/CD1Inside.jpg

MSD (basic version), Through hole old school PCB. Cast aluminium box.

http://www.4secondsflat.com/MSD%20HI-6%20Inside2.jpg

It think the quality shows with the Daytona PCB, but the box is cheap extruded aluminium, perhaps $10 worth. If we housed our CDI+ unit in one of those boxes we could shave $200 off the asking price!

Both these boxes are roughly twice as big as a Bosch CDI.

It was a challenge for us to get all the features in that little box!

Funny thing, my dad was a "power system" type of EE. He really though analog was the better choice. That was 20+ years ago. He had good, solid reasons for why it would be better. But advancements in digital processing have exceeded almost anyone expectations.