Author Topic: CDI ignition  (Read 145 times)

Jimr1999

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CDI ignition
« on: 30 Sep 22, 11:42 am »
Morning all, and here I go again experimenting.

This is a winter project for me on the engine.
The aim is to widen the power band of the engine by having self advancing timing as the revs build, Like most motor vehicles.
Peak power should not be effected as our engines are designed stock to only produce peak power at about 3500 revs.
Quite a few people add 40 of advance by filing the key. I have not. Doing this shifts the peak power up the rev range.

with a 7:1 gearing plus TAV overdrive at 1:1, 6000 revs would give approximately 60mph!!! on a 17" wheel + tyre so our rev range for power is probably best low down, and ideally over as wide a band as possible. If I were a Kart with small wheels, filing the key would be a great advantage where I needed it as the gearing is lower. As we state 35mph as an aim for the CycleKarts, having a wide band of power around 3500 revs should be the aim. (Errata: the 60MPH figure is wrong. My calcs did not convert KPH to MPH - My bad should be 40 MPH ish)

I have come across a fellow  in Canada who is producing basic CDI kits for our engines and persuaded him to ship me one.
If it works it should put less stress on the engine, have a better fuel economy, a wider power band, wider torque band and be easy to start.

These things are quite new and the fellow is a small business trying to establish a market. It is an experiment and I may go back to stock if it doesn't work out. If I were you and you were thinking of giving it a go, I would let me spend the small amount of cash on it first and see how it works out.
Thoughts please


https://www.youtube.com/watch?v=NNaAdmFazp4

« Last Edit: 04 Nov 22, 08:38 am by Jimr1999 »
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Moogie38 (Noel)

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Re: CDI ignition
« Reply #1 on: 30 Sep 22, 12:07 pm »
Very interesting,  looking forward to reading your findings.
The older I get, the faster I was !

Ian F

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Re: CDI ignition
« Reply #2 on: 30 Sep 22, 07:40 pm »
Looks good Jim and variable timing would certainly be an improvement. I imagine it will need a power supply, crank sensor and something to measure load such as a MAP or TPS sensor,

Jimr1999

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Re: CDI ignition
« Reply #3 on: 30 Sep 22, 08:24 pm »
From what I can gather, it needs a 12 volt supply and draws very little current. , A 1 AH battery should last eight hours. It has a sensor on the flywheel and a CDI unit to handle the timing/advance depending on revs. This is attached to a coil pack and the plug.
His Facebook page is not too descriptive as is the YouTube channel. If it works out, I will post my results, if not I have blown a hundred dollars and shipping. And we all know either way.
Very few videos of the results yet from buyers on YouTube, as I say, all new. He says I am the first Brit to have one... Watch this space, it will be November before I get to it as I will be away
... You can lead a horse to water, but a pencil must be lead.

Ian F

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Re: CDI ignition
« Reply #4 on: 30 Sep 22, 08:44 pm »
So there's no load sensing then, I guess it will just be a simple 2D rpm advance map. Not a bad price if it works as a Megajolt or Nodiz is more than that, but they will support a 3D map

Jimr1999

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Re: CDI ignition
« Reply #5 on: 30 Sep 22, 09:43 pm »
From what I can gather that's about it, as I say any solid information is scarce, still, a 2D map beats no variable timing for widening the power band and optimisation of the engine. It is slightly better than a set of points and a vacuum advance with the coil pack too😊... Time will tell
... You can lead a horse to water, but a pencil must be lead.

StefanN

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Re: CDI ignition
« Reply #6 on: 04 Nov 22, 05:54 am »
This is an interesting experiment.   Has it arrived?   I’ve always thought the torque on these engines is remarkably flat and hence the power linear with RPM, within the narrow RPM band they show.   I’d be interested to see the results from a dyno test of a stock engine across a wider RPM range - say 1000-6000.
« Last Edit: 04 Nov 22, 06:15 am by StefanN »

Jimr1999

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Re: CDI ignition
« Reply #7 on: 04 Nov 22, 07:18 am »
Still waiting for it surface mail from Canada. I am almost giving up hope! I have a house project that will take me up until Xmas to fully finish at the moment Stefan so news on this will be after that IF it arrives. (I will also post here when (if) it does).
I do not have a dyno, but the system seems easy enough to mount and swap so a direct comparison would probably be relatively easy to do with the motor rigged to a bench. I can't imagine the overall power being too much more with the way we utilise the torque convertor as maxing it out rarely happens, I can see that it *should* widen the torque available as the firing point should be more optimal across a greater range if it is set up well.
Watch this space.
Jim
... You can lead a horse to water, but a pencil must be lead.

Jimr1999

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Re: CDI ignition
« Reply #8 on: 25 Nov 22, 08:13 am »
Nearly two months down the line and still no sign of the kit. Good job I am busy putting a posh porch on the back of the hacienda.
Just read that surface mail from Canada can take up to 84 days! (Phileas Fogg seemed to do more and quicker!) - and then it has to clear customs in the U.K. (possibly up to 2 weeks) ... I expect the huskys are on strike at the moment as well for improved chow and better conditions  ;)

... As always, watch this space.
Jim
« Last Edit: 25 Nov 22, 08:16 am by Jimr1999 »
... You can lead a horse to water, but a pencil must be lead.