Really? And you have extensive data to corroborate that, right? Most all engine thermodynamics research indicates
that once a minimum spark energy level is attained, little benefit results. The typical minimum spark energy is about 50 mjoules.
The Bosch CDI produces about 90 mjoules. Since your CDI is producing less voltage than the Bosch, it's highly likely that your
unit produces less energy even with the second spark, since your published data indicated that the second spark has a much
shorter spark duration than the first. Remember, most all present day automotive ignition systems use inductive discharge,
where the spark duration approaches 1 millisecond, over about 10X the CDI's spark duration. One of the key benefits of the
inductive discharge ignition is lower emissions levels indicating a more complete burning of the fuel charge resulting in better
energy conversion.

Much appreciated. Kind regards.

Annnnnd Loren’s back.

This thread is full of dyno plots. Is that not data? Loren, to be honest, I’m past caring about this tiring debate. I don’t need to prove anything since hundreds of customers are happy and that is what I really care about.

Check out the Classic Lemans video that I filmed below. It was a real honour to see that a significant number of these cars run CDI+. Why would they do that? And yes, that is actual real Gerard Larousse driving 39.

https://www.facebook.com/ClassicRetrofit/videos/654173008295123/

We didn’t actually set out to produce a performance product ( the design goal was a reliable alternative to repaired units ). And yes, we have had a few bumps in the road but we are upfront and transparent about everything we do.

It is only through engine builders and customers TELLING US that the boxes make more power that we know about it! From this perspective, the ‘data’ is from others thus completely independent.

Please do design, test, manufacturer, sell, support and continuously refine your own ignition system with a lifetime guarantee. Go ahead!

As most 911 DIY owners know, all it takes to "get more power" is a 13 mm wrench and a very small turn of the distributor (advance).
Power is all about timing advance on an engine. It's that simple to sell any engine/performance product! And then relate it with
a key feature of the product, e.g. more spark energy.

......aannnnnd a 45 year old Bosch CDI that was designed more than 50 years ago is all you need. .......annnnnnd new technology and components are not needed.

Annnnnd my name is Dave....

No. When you have a better combustion e.g. a faster flame front you need LESS advance. Ask any twin plug guy.

Lots of engines respond to more advance in the mid range but need less at the top end or they wil detonate. I’ve seen an RS run 36 degrees on cam in the mid range but reduce to 29 at the top end. You simply can’t do that with bob weights.

I’m assuming most engine management systems works like this: The most advance is found under low load and mid-range RPM conditions. Close to redline the timing is dialed back.

At least that’s how the 3.2 and 3.6 maps are I dealt with are structured.

The engineer in me wants
1) the ignition timing plots to go along with these chart below, in the CDI+ I guess there will be two for each run, one for each spark, and
2) the margin of error in these measurements

if you don't mind adding or specifying them.

But I don't want any flak so please feel free to ignore this request.

Do a little reading about the need for twin plugs as it relates to timing and high CRs before bringing that issue into the discussion, e.g. the 964/993.

Very good questions to ask, i.e. as it relates to stock timing.

pmax, I’m an engineer too ;) There are very few rolling road dynos capable of independent timing verification. The standard SC plots were done on factory timing. My car runs a custom map but still has the same factory timing at the top end.

On our website, there is a test report conducted independently on a full engine test cell which DOES have an independent timing sensor. This clearly shows increased power using the exact same timing curve as a Bosch unit. See page 7. The thin red and blue lines are CDI+ (thick lines are Bosch). Timing is plotted at the bottom and note that CDI+ has slightly LESS advance on the later plots.

Here’s a link:

http://www.classicretrofit.com/media/1035/classic-retrofit-cdiplus-test-results.pdf

Energy transfer to the spark with the Bosch will likely be 7 or 8 times less than the 90mJ you quote, and based on the width of the scope profiles for the CDI plus it is probably even less. However, energy to the spark is not the only parameter that makes one ignition system better than another. Spark power is arguably more important, plus perhaps duration which can be compensated for more effectively with a CDI by using several high powered sparks in succession(not including MSD that has too much time between sparks). Most inductive ignitions transfer 3 or 4 times the energy into the spark but with less intensity and the trailing portion of the spark is weak and usually too weak to ignite fuel and only erodes plug electrodes. There are other advantages to a voltage controlled CDI especially on old cars prone to fouling plugs with small diameter distributor caps. I still need to do a short article on plug fouling, but recently and rather by accident I discovered the primary reason why CDI is vastly superior in overcoming spark plug fouling. It is really quite amazing and not what I've seen published before. Fred

380HP, 330 ft lbs. That is all.

https://m.youtube.com/watch?v=UtnrLj1pVF4&fbclid=IwAR1LtepZA28zf4b8ZxhJU MuNld291vwBJlgiX1iDi9NSfH7vdkUvo3LxVdQ&feature=you tu.be

Enjoy!

That's awesome!

There's going to be a CDI+ under the tree for my 3.2SS MFI build...... thanks to Jonny H for bringing this to market (plus all the other great products!)

Johnny, your CDI looks to be a very nice unit. I have a similar car 83...911 sc ROW and my issue is cost....under 2500 rpm where I do not spend much time your unit really performs...above that rpm it is basically a wash.

So, a thousand bucks (I believe have not checked lately) for just a few ponies is not cost effective unless on the track eeking out the last drop of blood...…


Have you posted the same style dyno of your product say against an MSD unit? You may have but there have been a lot of posts about your product.


AS I said....I appreciate those that develop things for our older 911's.....thanks.

^^^ Haha, The definition of a back handed complement.

Hey Johnny; thanks so much for spending years of your life developing something worthless. [emoji38]


Sent from my iPhone using Tapatalk

No, not really...it does some good but not, as I see it, equitable to the money spent to acquire it...this is a market place in that respect and I meant what I said.

I appreciate those willing to gamble in the market but that product must perform to the level of money needed to purchase it.

I do not see that fair trade.

This looking at what he provides...the stock SC w/wo/ CDI and his product.

Throwing a non stock cam in the mix is basically meaningless for measurement here.

The compliment was honest....as was my evaluation and why.

The product has viability which is more valuable than any small performance gain IMO:

- solid state and all new means less chance of break down
- looks traditional Bosch not Chevy hot rod (most aftermarket CDI I see have sort of cobbled together wiring and installation)
- could allow for future updates including switchable maps for race gas or hot weather, etc. (I’d need this in order to part with my OE stash of CDI boxes)

I have to agree with Jeff above.

Plus best value for me in that it replaced an old and risky device with something modern, adjustable, that increased performance in the area where I spend most of my time in the lower rev range.

The ability to avoid a costly 10k rev tacho conversion and have an adjustable rev limiter is a big bonus.

Cost difference with other alternatives is not big.

To me it represented good value. Thanks to Jonny for helping keep our older cars running well.

Tim