Enhanced spark energy For electronic ignition !

[KTy]

Alloha,

To make a long story short,

1. I looked at the specification of the ducati CDI, the important part is the maximum voltage of the condenser: 400Vpp (peak to peak) !

2. I measured on my stock PX125E between the white (ground) and the green (AC voltage to charge the condenser), ~90VAC (=125Vpp) at idle, and a maximum of ~150VAC (=212Vpp) at mid-rpm (~120VAC (=170Vpp) at 8000tr/min)

3. I created a small electronic module

4. After this simple modification, I measured between green and white a maximum of ~190V (=270VAC) and ~160VAC (=225Vpp) at 8000tr/min far below the 350Vpp maximum input !

So, I've been driving with this little modification for hours, nothing to worry about !

A better spark gives better combustion, less emission, so an *overall* performance enhancement (do not expect +50% !!).

Cheers,

EDIT 2011: about 250 modules in use !

EDIT 2012: NEW version available ! Order it online www.kytronik.com !

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Bearbeitet 3. Oktober 2012 von KTy

[KTy]

Not so many people seem interested in this kind of project... (

Anyway

So, I've made some datalogging with multiples configuration (condenser, vCDI or not,...);

All blue curves are taken between the white (ground) and green point in the above schematic.

What I can say is:

* On a stock engine with *my* variable ignition timing module + a big condenser, spark energy is increased by 40% ! :)

I'm looking forward to compare on a stock engine on a dyno without condenser, without a vCDI module, and after with vCDI module and with a condenser... There could be some nice surprise :wasntme:

Bearbeitet 17. März 2012 von KTy

[HansPils]

Nette Idee, eine Zündung mit einem Kondensator als temporären Energiespeicher für höheren Output bei hohen Drehzahlen auszustatten.

Nur beschwert sich hoffentlich kein Bauteil über mehr Überspannung von 100V.

Ist das der Schaltplan von unserer stinknormalen PX Blackbox?

[KTy]

Ist das der Schaltplan von unserer stinknormalen PX Blackbox?

Well, I guess so, but even if it's not exactly the same, it should be *very very* similar

The basic idea of the condenser and the diode is to use the negative aternance of the charging coil. Because in normal operation, only the positive alternance is used, it's "a waste" !

[HansPils]

Leider. Wenn man die Zündung mit Gleichstrom versorgen würde, könnte man auch so die Leistung steigern.

Lohnt sich aber nur wenn die originale Zündung mit der Leistung am Ende ist und bei wem ist sie das schon?

[KTy]

I'm not sure I have understood what you meant, but I will have some dyno with and without condenser to see if it's really of *any* use...

[gonzo]

Lohnt sich aber nur wenn die originale Zündung mit der Leistung am Ende ist und bei wem ist sie das schon?

He was refering to the fact, that a normal CDI Unit is not at its limits when in normal use.

I'm very curious about your dyno test, after that we will see if it its of any worth for the scootering community or just something for "race use scooters" only!

regards

- gonzo

[HansPils]

Thank you gonzo.

[KTy]

He was refering to the fact, that a normal CDI Unit is not at its limits when in normal use.

He's right. In normal condition the CDI unit is working "okay". But if one can improove spark energy at all rpm, then the engine will start better, have less emission and probably (we will see ;) ) be a little bit more powerfull...

[MiNiKiN]

Kty: Hope you will not meet the fate of the "Hot-Wire" (Picture from SIP), which was completely torn to tatters in this forum. Nevertheless I built one of my one and found the engine to start better and having better idling and higher ignition rate in lower revs (not evaluated by measurement and therefore worth nothing in terms of science). This "Hot wire" thing is said to have a similar condenser effect by avoiding stray fields due to the use of cable shielding, which then leeds to a more stable and longer spark.

Would be an interesting combination.

Good luck for your dyno tests

Marcus

[KTy]

Yes, of course !

Anything that can give you a better spark is good for your engine performance, but it is also better to reduce emission !

I have now several other friends riding with "my modification", they all feel that the engine is easier to start, smoother to drive and it responds better at low rpm...

Dyno-test will tell the truth

How did you build your "Nology" cable ?

[oli-san]

I would love to try such a mod on my 136ET3.

Is there anything to worry about with high revs (11000)?

How did you attach the actual parts to the CDI? Somehow, I couldn't find a picture of the hardware.

Oli

[KTy]

I would love to try such a mod on my 136ET3.

Is there anything to worry about with high revs (11000)?

How did you attach the actual parts to the CDI? Somehow, I couldn't find a picture of the hardware.

Oli

Unfortunatly, I cannot guaranty that it will work perfectly :wasntme:

BUT, as far as I know, the "only" thing that could happen is that you blow the CDI unit ! :haeh:

And another important point; the voltage is *decreasing* with the rpm ! So there is nothing to worry for the CDI at high RPM. The maximum voltage is usually around 2500-3000rpm.

Before mounting the circuit, it could be a good idea to measure the maximum AC voltage that you have between the white and green wire on your CDI unit. Again, if you have less than 200VAC, you're safe, you can try the modification without fearing to damage anything.

I haven't made any picture but it's fairly simple, I'll make a drawing !

Have fun

Edit: Here you go !

Bearbeitet 31. Januar 2006 von KTy

[atom007]

genial

i'll try it, i have the cdi from marc74, i don't care to burn it

[MiNiKiN]

@KTy: I used a standard ignition cable with copper wire - wrapped some shielding mesh around its circumference - wrapped the whole lot in shrinking tube and connected the shielding near the spark plug to ground.

cheers

Marcus

[HansPils]

@minikin222: hast du selber gemacht?

[KTy]

@KTy: I used a standard ignition cable with copper wire - wrapped some shielding mesh around its circumference - wrapped the whole lot in shrinking tube and connected the shielding near the spark plug to ground.

cheers

Marcus

hum... Yeah, the more I think about it the more I think it can actually do something :)

It's like a condenser, indeed !

Thanks

[MiNiKiN]

Yes, I´ve done it myself - ja selbst gemacht!

M

[kan_Kuma]

@KTY

The 200V AC you've measured between red and white, was that measured under load? Meaning, was the engine running and the wires connected to the CDI?

We also had around 200VAC (give or take 10%) but without any load on the stator. Engine, or rather only a testbed, turned by a drilling machine at 3000rpm

I find this nevertheless very interesting and worth trying. Do you think there is a chance that the spark, due to the higher charge of the igniting condenser is also igniting longer than with stock? This would explain why your engine is having a smoother idle.

Keep up the good work

Cheers

Chris

[MiNiKiN]

What´s the most interesting fact in this topic is that yet a few believe what a hundred were bitching at a few months ago :puke: .

KTy you lucky bastard are hopefully not able to read the articles you get when entering "NoLogy" into the search engine. I suppose you´d been dismembered there saying anything like a condenser effect improving idle, fuel efficency or power.

You seem to be a messias making people believe - stay tuned

Marcus

[KTy]

@KTY

The 200V AC you've measured between red and white, was that measured under load? Meaning, was the engine running and the wires connected to the CDI?

We also had around 200VAC (give or take 10%) but without any load on the stator. Engine, or rather only a testbed, turned by a drilling machine at 3000rpm

I find this nevertheless very interesting and worth trying. Do you think there is a chance that the spark, due to the higher charge of the igniting condenser is also igniting longer than with stock? This would explain why your engine is having a smoother idle.

@kan_Kuma: First, it's beetween GREEN and WHITE (ground) , and yes, it was measured on two differents PX125E engines running for true :)

Actually, the important thing is, what I measured was below 200VAC (about 170VAC), to ensure that after the modification, the engine won't deliver more than 350VAC (because there is a 400Vpp inside the Ducati CDI).

Adding the diode and the condenser makes a voltage-doubler, but with only 3 periods (the flywheel has 6 poles) to charge the condenser before the spark is ignited, it is not really doubled, it's about 60% more.

As I only increased the voltage of the capacity (I didn't change any resistance), the spark is probably longer while more than doubling the energy (E = 1/2 . C . V²)!

I'm not saying it's risk-free, but for me, it is worth trying

I think the main reason why this trick is working (at least for me !) is that the Ducati CDI was not design specificaly for vespa, so it is over-rated compared to the stator :wasntme:

@minikin222: It has to do with my french accent...

[da Huber is]

Eine schöne klassische Spannungsverdopplerschaltung. die Ladespule muss natürlich dann die 4 !! fache Leistung bringen

[HansPils]

Ala Greinacher Kaskade. Ich glaube das schafft die Spule schon, auch wenn's die negative Halbwelle in den Sack haut.

[KTy]

Eine schöne klassische Spannungsverdopplerschaltung. die Ladespule muss natürlich dann die 4 !! fache Leistung bringen

Exactly

It's a simple way to use the negative alternance of the signal !

No magic here...

Dyno will tell

[atom007]

2. I measured on my stock PX125E between the white (ground) and the green (AC voltage to charge the condenser), ~90VAC (=125Vpp) at idle, and a maximum of ~150VAC (=212Vpp) at mid-rpm (~120VAC (=170Vpp) at ...

I tried to measur this today :-/ I read somthing between 0.3 and 10V :plemplem: its an instrument promising true RMS maybe its not true enough??? or it was too cold

[KTy]

I tried to measur this today :-/ I read somthing between 0.3 and 10V :plemplem: its an instrument promising true RMS maybe its not true enough??? or it was too cold

Oddly enough, a friend of mine had the same issue... I can only think that this is caused by a weird signal (not sinusoidal at all) from the stator. What are the exact models of rotor/stator and CDI unit ?

I will ask my friend to see if we can find some related facts !

EDIT: He has a PX200 from 1995 rotor and stator and the blue Ducati CDI...

Bearbeitet 28. Februar 2006 von KTy

[Lacknase]

Alloha,

To make a long story short,

[...]

Of course, it would be interesting to see the result on a dyno... :wasntme:

[...]

:wasntme:

dyno will tell

Exactly. Yet, the question persists: what?

Just curious ...

[atom007]

Oddly enough, a friend of mine had the same issue... I can only think that this is caused by a weird signal (not sinusoidal at all) from the stator. What are the exact models of rotor/stator and CDI unit ?

I will ask my friend to see if we can find some related facts !

EDIT: He has a PX200 from 1995 rotor and stator and the blue Ducati CDI...

Its a one year old PX Lusso stator and an one year old HP4, the CDI is the black ducati (very old?).

[KTy]

Its a one year old PX Lusso stator and an one year old HP4, the CDI is the black ducati (very old?).

So, as far as I can tell, it is a totally different configuration, so I think it maybe related to your multimeter...

If you have the chance to plug an oscilloscope, I would be interested in seeing some curves...

As for the dyno, normally I have an appointement in 2 weeks time ! :sabber: I will have lots of stuff to measure !

[KTy]

15 french scooterists running this thing for some months now with no trouble at all, easier cold starting and smoothier ride And still no dyno nor any emission measures...