Roll Your Own CDI

Are You Going to Roll Your Own CDI?

  • Total voters
    123
Rohmell, how much clearance do you have from the bottom of your spark plug porcelan to your top tube on the frame? do you have a 45degree head? I have a stick coil i can ship to you for testing.
 
Flybytaco, thanks for the offer, but I do have various coils that I am using for CDI testing.

I'm thinking maybe those coils are designed for a lesser duty cycle since they fire every other revolution divided by the number of cylinders in the engine being used, so for example in a 2 cycle, 3000 RPM, firing every revolution= 3000 pulses per minute, 50 pulses per second

In a V6 at 3000 RPM, would be 3000/2= 1500/6=250 pulses per minute, 4.16 pulses per second.
In other designs that fire on the exhaust stoke as well as the compression stroke, you would have 3000/6=500 pulses per minute, 8.3 pulses per second.

I wouldn't want to blow up a coil on yuh.
 
Flybytaco,
From the bottom of the spark plug porcelain to the top tube on the frame is 5 inches, and yes, I am using the slant head. Will it fit?
 
I'm having trouble laying out the components on a board. I guess I'll be using a universal PC Board from RS. I've never done this before, so I'm very excited for this project. Could someone please show me how it should look on both sides? I'll be assembling the basic CDI from the first design, then going from there. I'm using the suggested components and (2) of the big capacitors. I saw how they connect off the board, but I'd just like a nice neat way to connect them on a board. Thanks guys.
 

Attachments

  • boardlayout.jpg
    boardlayout.jpg
    25.7 KB · Views: 698
impression said:
yes it would

however i'm wondering what diodes and semi conductor is in the picture there as i would build one this weekend :)

I would also love the schematics to the binary one he has a couple of pages back :D
Click to expand...

Any diodes and SCRs that you have lying around that are at least 400 PIV.
 
skrew37 said:
Would this work as well?
Click to expand...

Hi rohmell-I can billed this from the pic 'paint by #s' but I don't know if
this is an advancing and then retarding cdi? or a stagnant timing cdi?
I'm good with nut and bolts but this is beyond me I'm looking for (15-20) btdc @ 1000rpm (0) out tdc @ 4500 rpm.+ or - I can tune around that
 
Last edited:
ducedave said:
Hi rohmell-I can billed this from the pic 'paint by #s' but I don't know if
this is an advancing and then retarding cdi? or a stagnant timing cdi?
I'm good with nut and bolts but this is beyond me I'm looking for (15-20) btdc @ 1000rpm (0) out tdc @ 4500 rpm.+ or - I can tune around that
Click to expand...

This version had no RC network for adjusting the timing.
 
You must log in or register to reply here.
Back
Top