CDI+ advance/programming issue
 

I'm running my CDI+ in full control mode. The dizzy is locked. Here's where the dizzy rotation is...

http://forums.pelicanparts.com/uploa...1653346146.jpg

Here's my CDI+ curve:

http://forums.pelicanparts.com/uploa...1653346146.jpg

The problem is that according to my tuning software, my advance is maxing out at 20 degrees. The minimum appears to be 10.5 degrees, which is occurring at about 1K, which corresponds nicely with the curve. It's my understanding that this is showing that the dizzy rotation is providing 10.5 degrees of advance, correct? And as such my advance should be maxing out at above 30, correct? (a bit too much, I know).

As you can see my trigger advance is set to 40, which should give lots of room. Is the problem that my dizzy needs to be rotated more? If so how much would one try for? And I take it if I do this I need to reset the CDI+ curve, correct?

Thanks for your input!!!

It’s been pointed out to me in my other thread that with my setup the tuning software I’m using isn’t seeing the timing accurately. So, it seems best to ignore that data. I’ll add that the cdi+ software does show the timing advancing along the curve all the way up to max, so that makes sense.

Gotta love this board!!

Reading through a few other threads on this topic I have a few questions, hopefully someone with experience/knowledge can chime in.

First, I rotated to the timing mark on the flywheel with a timing light- 5 deg. I locked the dizzy. Next I set the CDI+ in full control mode.

The curve above was written to the unit.

I'm confused about the trigger point, what should my Trigger point be set to? I have it set in the profile to 40 deg to allow for enough adjust room. But, given that my dizzy is rotated to 5 deg, am I interpreting correctly that in order to allow for enough adjust room the trigger point should be set to 10 deg?

And, If I do that most of the curve will be in the red zone, so then I would have to rotate the dizzy to 20 deg AND reset the trigger point to to allow for 40 deg of advance, correct?

If I rotate the dizzy with the engine running and this profile applied, I should see no difference in rpm, correct (?), since the CDI+ will be retarding the spark signal? Or does rotating the dizzy to 20 deg then change the baseline advance, so the cdi+ is then adding 24 degrees of advance at the top of the curve for a dangerous 44 degrees?

This may be a stupid question but how do I find the 20 deg mark since there's no other notch on the flywheel? Is it literally 3x the distance along the flywheel from the 5 deg mark?

Two things - have you read the FULL manual available on the Classic Retrofit website? If not you owe it to yourself to read the whole thing.

Also, check off "adjust room" on the software. It will show you the max advance you can run for a given trigger point.

If you take the time to read and fully digest and understand the problem you'll be fine.

PS you have, and are using, a dial type timing light to verify timing, right? Otherwise you are shooting in the dark.

I'm a little confused about the full control setup process. I watched the video several times, can someone please verify this is the process?

Set the curve with timing set at 5 degrees.

Adjust the tigger point to allow for more working room.

Send the file to the unit.

Adjust the dizzy with timing light to match what's on the software curve.

Correct?

CDI+ Manual

Page 25:
"Trig Advance
The amount of advance in engine degrees that the distributor should be set to. See Adjust Room in
the following section for a detailed explanation of this setting."

Page 28:

"Adjust Room
The CDI+ uses a microprocessor to calculate the exact time to fire the spark depending on the engine
RPM and the advance required. In order to do this it must be able have the distributor trigger signal
before the spark is actually required.
[The way the CDI+ achieves advance is to receive the trigger signal from the distributor 'early' and
then delay the firing of the coil according to the advance curve. To get the early signal we must
rotate the distributor further in advance. We call the value for the distributor rotation 'TRIG
ADVANCE'. The angle of advance at the distributor should be half that of the value of TRIG
ADVANCE.
Now, let's say the TRIG ADVANCE is set at 15 degrees - it should be clear that any advance in excess
of 15 degrees would not be possible as the spark would have to happen before the trigger. In
addition, there are other delays that compound the time required by the unit, read on... ]
The total amount of time required we call the 'adjust room'. The adjust room required is a function
of TRIG ADVANCE, the amount of advance required and also the input delay through the points and
electronics. All of these combine to form an area that is potentially unreachable on the graph. This
can be displayed on the graph using the 'show adjust room' checkbox. If the area is breached the
'ADJUST' flag will also be illuminated. If this happens, then the distributor will physically need
turning further in the advance direction and the TRIG ADVANCE setting changed to match. In
practice, it is not really an issue as most cars do not require more than about 30 degrees. If more
than this was required, it just needs more physical advance on the distributor. In extreme cases this
may require turning the distributor one tooth on the drive gear."

Page 29:
"Full Control mode.
In Full Control mode, the distributor weights and springs are physically locked..."

continued on Page 30:
"The total ignition timing is controlled completely by the unit. Remember though, that the static
timing of the distributor is still offsetting these values.
For example, on an SC, the static timing at idle is set to 5 degrees BTDC. Using the graph above, the
advance shown is 0 on the graph at 1000 RPM. This means that the total advance at 1000 RPM is 0 +
5 degrees. At 6000 RPM, the graph shows 24 degrees but the total timing will be 29 (+ 5 for the
static timing)."

So even though your distributor is locked (causing no CHANGE in timing relative to RPM), the actual timing is whatever position the distributor is set to (aka static timing) plus what the CDI+ is adding.

The distributor needs to be set to a position where the CDI+ is getting the signal from the distributor BEFORE it is needed. Which is why the static timing should be set to half the TRIG ADVANCE value.

This adds up to the area displayed with the "show adjust room" checkbox. Interpret that as "adjustment area we can't reach based on the static timing/TRIG ADVANCE as currently set"

DISCLAIMER: I'm still making notes before having CDI+ control my timing, so take the above with a grain of salt.

Ultimately though, I think you should be able to setup your timing light and confirm the true overall timing, regardless of whether it's set by the distributor, CDI+ or both.

This thread underscores the fact that once you put the CDI+ in full control you have all the power in the world to make adjustments - for better or worse.

If you don't become enough of an expert on your own so that you can sufficiently understand, test, verify with a timing light, adjust, verify again, etc, add infinitum, you are running the risk of asking the wrong question, misinterpreting the correct answer given you by a well meaning forum member, and getting the wrong result.

That said, groovydude, I think you're on the right track. Try it, verify it, and don't drive the car at full load/RPM until you're sure you're only getting your intended max timing.

Some of the questions you asked earlier in this thread lead me to think you either don't have a dial type timing light, or aren't fully understanding the one you have. With a dial type timing light you are best to ignore every other mark on the crank pulley and refer only to TDC and use the dial.

PS - With the CDI+ in full control mode you have three ways to adjust the timing:

1. the position of the distributor
2. the trigger point in the CDI+ software
3. the curve of the software

Change one, and you'll change the timing. Change two in equal but opposite directions, nothing changes. Change all three and who knows what could happen? (You get the point)

how did you "lock the distributor". Did ou remove it and then rotate the advance mechanism and fasten it to that position?

Did you use one of these?

https://cdn.shopify.com/s/files/1/00...9700_1200x.jpg

I locked the distributor with the brass thingy that Classic Retrofit sold me (see pic above).

This is a response from Jonny H from Classic Retrofit: If you are wanting a max advance of 23 deg on the graph (before adding the 5 static to make 28), you'll need to set TRIGGER to at least 35 (so it is not in the red) and rotate the distributor 35/2 = 17.5 degrees. Whatever changes you make, always verify with a timing light.

I've got a dialed timing light on order, I'll post after it's all set.

Please explain what benefit you've gained, given all your expense (+$750) & effort, from switching from a stock system.
Surely you're aware that simple timing changes can be made by just re-positioning the distributor. Have you done before and after dyno tests?

Like a moth to a flame…

Any chance you are here to suggest he send his original CDI to YOUR COMPANY for repair?

https://www.systemsc.com/products.htm

If you really are that desperate for work, why don't you advertise in Panorama or something instead of sneaking around here wasting everyone's time by asking questions you should already know the answer to?

It’s really pathetic, he peddles the same garbage in every CDI+ thread. So many sour grapes and so much butthurt.

Please avoid ad hominem posts. Please respond by technically challenging the issue being discussed instead.

Consider reading post #11 here; http://forums.pelicanparts.com/porsche-911-technical-forum/1119451-best-ignition-coil-use-cdi-classic-retrofit.html

Yes! Have the CDI repaired here for less with equal or better performance;

https://www.pelicanparts.com/catalog/SuperCat/5871/POR_5871_ELIGNT_pg2_bosch-cd-ignition-units.htm

Benefit? I replaced a 40 year-old box of electronics designed in the middle of last century with something solid state and state of the art for one. Unfortunately, I don't just have a dyno laying around my garage so I can't "confirm" that it was worth the spend. But, in addition to the aforementioned, the timing curve adjustability/tunability and the second spark feature made it a worthwhile spend in my book.

And if you're seriously going to ask for dollar-for-dollar justification of spending on cars, a Porsche forum is the wrong forum IMO.

Many have done, here's one:

http://forums.pelicanparts.com/porsche-911-technical-forum/894670-classic-retrofit-cdi-dyno-results-11.html#post10483546

That's a non sequitur! What does "state-of-the-art" mean. Just more components added without a measurable improvement,
and a reduction in reliability because of the added number of components. You're aware that a system's reliability decreases
with the increasing number of components.

You really need to quantify exactly what was really gained!

You obviously haven't viewed the very marginal "second spark" via an oscilloscope.

Life's boring?

Read post #106;

"Thanks Johnny H, at last, for the good comparative data. Some of the very small increase in torque
at various points can possibly be explained by the very small increase in advance of the CDI+ over
the Bosch CDI, i.e. for every one degree in advance, the typical increase in HP is about 3-4 HP.

Bottom Line: The 50 year old Bosch CDI technology doesn't "leave much on the table". "

and review the dyno data;

http://forums.pelicanparts.com/uploa...1653522491.jpg

Simple timing changes yes, but a distributor cannot produce a curve with a mid range 'bump' and then a reduction in advance at high RPM which is what these engines respond to.

If you were to maximise advance for mid range power by moving the distributor, there would be too much advance at high rpm and the engine would detonate.

Real world example: a 911RS has peak torque at around 5000 RPM, but the distributor is not fully advanced until 5800 RPM. The factory spec max advance for this engine is around 35 deg. This car was mapped on a rolling road using headphones to detect knock. It responded exceptionally well to having almost 40 degrees of advance at peak torque (5000 RPM) without any signs of knock. Beyond 6000 RPM, knock was evident so the advance was reduced down to 35 degrees at the top end. The rate of acceleration of that car is phenomenal now, even though the headline max HP is no different.

You're joking, right?

^ No joke. I guess you haven’t been to many dyno sessions.

Pretty much all profession dyno tuners use headphones. Your ear / brain has more signal processing and computing power than any chip.

There are lots of system out there such as the one below, educate yourself:

https://phormula.com/product/phormula-ks-pro-audio-knock-detection/?gclid=CjwKCAjwyryUBhBSEiwAGN5OCCg_HjiewfZLzqLJS6k F30zGHjkZJfcQC0rPKoYnaOP09dyACzUgZxoC7-4QAvD_BwE

Not really! Tuning engines without knock control is problematic, e.g. the 911 3.2.
The variables which are not controllable, typically contribute the most to detonation and can't be fully simulated during dyno runs;

1. High engine load conditions like climbing a long steep grade.
2. A hard acceleration on a very hot day in the high RPM range, e.g. a track day.
3. Compounding conditions 1&2 is having a fuel octane level which is less than what's presumed, i.e. a lower octane than what's listed on the pump. It happens!

Those also buying the so-called 911 3.2 "performance" chip typically overlook these issues too!

^ I think you'll find that ears have been around a lot longer than knock sensors. Ears are old tech so you should really like them, no? I'm quite attached to mine.

p.s. Hijacking every thread about CDI+ is getting pretty tiresome. :rolleyes:

I think it's pretty entertaining !

My CDI+ is working well btw.

I'd rather end this discussion of the merits of a CDI+.

Getting back to what this thread started with - setting ideal timing/spark advance using a CDI+ in full control mode. I think Jonny H's manual is confusing. I appreciate the greater knowledge for sure. But, in his manual Jonny goes into great detail about the trigger point and an explanation of why half of that is the ideal rotation of the distributor.

My understanding is DON'T CONFUSE ROTATING THE DISTRIBUTOR TO SOME VALUE IN DEGREES THAT'S HALF OF THE TRIGGER POINT WITH DEGREES OF ADVANCE SET AGAINST THE FLYWHEEL WITH A TIMING LIGHT. One is twice the other. And, there's no easy way that I can see to measure degrees of rotation of the dizzy, although I'm sure it's possible.

What I've done is to set my trigger point to 35 degrees by Jonny's recommendation. I used a dial-type timing light to set spark advance to 28 degrees when the engine is at the top of my curve (23 degrees), at 3K rpm. If I were able to physically measure the rotation of the distributor past TDC, I'm guessing it would come out to 17.5 degrees at this mark. But I don't see any easy and accurate way of measuring the rotation directly.

Btw, I believe an advance of 28 degrees at 3K is what Porsche suggests for the 3.0 Euro. We could have a whole other discussion about what's ideal for a 3.0 US with ITBs, SSI headers and a cat delete. I have a dyno session scheduled in a month or so, perhaps I'll have more accurate info after that.