gy6 moto coil? anyone tried?

[HeadSmess]

if your playing with ignition maps only/ an ex temp gauge and wideband a/f monitor is needed. dyno is for swapping hardware and building customized fuel mapping.
without hardware swaps like exhaust etc there is just no need.

a dyno is used for evaluating what affects any changes make to the performance of an engine. regardless of what those changes are. some people dynotest just to show they make 0.3% more power by using ceramic bearings...


an ignition curve can have a major impact on performance with or without pipes.

how an airfuel sensor can have any bearing on determining correct ignition timing, iunno.

and how exactly would i adjust the fuel map on a steam engine if that was what i happened to be testing on the dyno that day?

maybe the same way i would tweak the mixture on a 32kv wound brushless motor, seeing as thats been on a dyno to see if the extra gain in power was worth the extra current draw due to rewinding with two less turns...

all this nonsense about "this retard curve is the ducks guts because i say so and it felt smoother and got up a hill 2km/h faster than yesterday" is BS. i want definitive results, not the propaganda spat out by a salesman or someone trying to prove what they cant.

but i do agree that an exhaust is a much better upgrade than some ignition circuit!

basic circuit works well enough for me. just some people are willing to pay for gimmicks if theyre convinced enough...

 

[Fabian]

The Jaguar CDI works well. If it didn't it wouldn't be on my bike.

Having said that, i want an upgraded version of the Jaguar CDI that allows me to interface between my laptop and the CDI so i get get inside the thing and have total control over the ignition timing in a stepless arrangement.
I want to be able to drag my mouse and adjust the ignition curve to wherever i choose it to be.

 

[briane]

wow thanks for all the great info - I know its not the biggest upgrade - but a hotter coil on the stock CDI would really help - and since that aint likely the best arrangement I thought I would build one myself - ordered a few 2 stroke coils to test out. Once you have the carb and pipe, the electronics seems like one of the biggest weak links, but thats only a guess.

How long do these stock CDI's last? I seem to only get 25-30 rides before they start acting up - they still work but are clearly weaker. Likely the quality/contruction of this BT151. What kind of rating on the BT151 are people using?

I'll be building that circuit and try a few tweaks - one thing I think may be missed is the harmonic resonance of the coupling cap - which seems important from reading up - that is...how would a solen peform against a nichicon against sprague against some other brand - one thing I can guarantee is the harmonics on each cap is different.

yeah - I dont know how scientific this all is - me I have certain runs I do on speed tests with the speedo - but that doesnt say anything except maybe 'goes faster' or not.

oh fabian - I get you - but thats going to require a digital CDI - which means it needs a computer inside it - so probably have to cut apart a smartphone and put it inside (at least without a dedicated digital circuit, ie cheap re-use) -plus power supply - excessive for my needs - yes highly desirable - but probably not realistic untill smartphones are the size of a fingernail and cost less than 10$ for the really good ones.

 

[Fabian]

I'm quite happy to pay $600 for an ignition system that does everything i want it to do, i.e. full laptop interface and applicable software, and also a permanent fixture on the bike.

A narrow band A/F sensor is pretty much useless for the application that is being discussed, because narrow band is only designed for closed loop operation. Full throttle operation falls outside the measuring capability of narrow band sensors. A wideband oxy sensor is the way to go in this situation.
Some of the German manufacturers use wideband oxy sensors in their vehicles.

 

[briane]

thank you all for letting me think out loud/ i have learned alot.
-------
to further the depth of conversation i was perhaps forgetting how seemingly easy it would be to use a laptop as the source plus a coil of course

Actually it is I who am humbled - I have learned a great deal - and now in the process of some reverse engineering on existing products - I'll just leave it at that, but I'm interested in the differences in the circuits using the C106D chip versus the BT151 - same idea, clearly different circuits and design though. I have thought that the electronics are really just providing some timing retardation/advancement - the big stuff is in the thyristor and the coil - so yes maybe I was joking earlier- but I was early saying that a laptop mounted to a front bike rack might be the easyest/cheapest solution for the ultimate 'fabian' solution. The magneto may also be an area of improvements (stronger magnets???, etc...)

I still want to see more schematics for CDI circuits, using the BT151 - but more improtantly I would like to see some schematics for circuits using the c106D as that seems what some of the higher end guys (ie jag) are doing - I have parts on order, but theres still a bit more engineering I have to just 're-invent the wheel'. I like to build what has been done first, get to really understand it, then go from there as then I can tweak minor part changes and get an idea not just for what does what, but what it influences.

I dont care if it has 10 or 100 parts in it - I want it to have good spark for starting and climb up those hills like a hunkered down soldier. As far as quantifyiing - for me Im ok with testing and personal biases for now.

 

[HeadSmess]

How long do these stock CDI's last? I seem to only get 25-30 rides before they start acting up - they still work but are clearly weaker. Likely the quality/contruction of this BT151. What kind of rating on the BT151 are people using?

one thing I think may be missed is the harmonic resonance of the coupling cap - which seems important from reading up -

still havent had a cdi unit fail? had plenty of old magnetos with the white wires burn out, but still, every cdi ive had still works.

bt151, whatever i got. think they were 600v. never bothered with anything else yet.

people are getting away with 275volt caps, so...

the amusing thing about all this "stepless ignition control" is that most engines, even racing engines, seem pretty happy with retarded idle, really quick advance from above idle to around 7000rpm, then start retarding again... whereas the stock HT engine is lucky to do more than 7000rpm.


but. i have contemplated this harmonic thingy...or maybe you mean reactance? ive been puzzling over how to use the reactance to "filter" the trigger in a way to achieve advance/retard without the CR circuit. iunno. amazing what you can do when being silly...

possibility of replacing a diode with a 1n5711 or 1n34. lower voltage drop allows trigger voltage and current to flow earlier, achieving advance. shame both components are rated at less than 100v inverse!

the other thyristor thingy you mention may require a lower trigger voltage/current. hence, more basic advance. other than that, i cant see any need for it. maybe a faster response time? less ON resistance hence more current flow from cap discharging making bigger sparks? iunno who cares me, maybe...


the easiest and best method, for all the diehards out there... use the existing magneto as a power supply, rectified and stepped up with a dc switcher etc. then add a hall effect sensor to trigger at 40-50btdc. let the unit work out all the retard required from that point.

so just buy mps or one of several other overpriced black boxes that really do little unless ones really working at the limit of performance...

really, i want the dyno just cus its easier than buzzing down the road after every new mod... especially when the mods dont work!

be nice to actually try timing one of these engines as well lol.

 

[HeadSmess]

just went through the data sheets. c106d is 4A 400v, bt151 is 12A, and cant see any other differences... trigger voltage current is hard to tell... really need the device on a board to test, sheets use different voltages etc on tests...

farnell says the 151 has a lower trigger voltage which is beneficial...

 

[Fabian]

i want the dyno just cus its easier than buzzing down the road after every new mod... especially when the mods dont work!

I agree.

The bullsh!t stops when the dyno rocks, plus you have a controlled set of conditions for consistency and repeatability when testing new components/designs against a baseline.

 

[briane]

just went through the data sheets. c106d is 4A 400v, bt151 is 12A, and cant see any other differences... trigger voltage current is hard to tell... really need the device on a board to test, sheets use different voltages etc on tests...

farnell says the 151 has a lower trigger voltage which is beneficial...

yeah - I ask cause the jag CDI uses the c10d6 - I have yet to identify a few of the diodes - but I'm pretty sure their zeners dropping down the trigger voltage - iniaitally looks like 2 .8 volt zeners @ 1 amp - have to check in more detail though - this seems proper as I suspect the trigger voltage on the c106D is a bit less than the input voltage -though I have not had my meter on it yet - so dunno

So my plan now is to build a multi-CDI unit with switches and a visual plug monitor built in - then I can do a big run (hahha - they just put a city speed tester right next to my house - perfect!)

then I can just flip the switchses between a few run, and try out 3-4 different CDI's, while also monitoring the visual appearance of the plug spark- not too scientific , but these will be 1/8 mile runs and so should give an idea of relative aceleration. I also have (will have) 2-3 coils I also be putting on switches, which should test about 10 combinations.

yeah - amp and voltage on the BT151 and c106D are pretty similar - I see the 400 volt in the jag, but sometimes you get better performace out of higher raterd parts - the 600 might be another test..

No - Im talking about harmonics - a bit of background - I come from the world of building high end amplifiers, guitars, instruments in general - so the harmonics of these brands is one thing I have an (empirical) grasp on. Though whats the effect? - I think it controls the re-actance capabilities - dunno.

 

[Fabian]

tractor pull dyno/ drag a refrigerator etc lol

or drag 10 trailers: