I will just say that there is a reason the Nascar teams had 2 systems installed on their cars... And the reason they used them, RULES.
Above roughly half the RPM range of a normal motor they do not deliver multiple sparks.
A standard electronic ignition with a high output coil is enough to light all but the most serious high compression or boosted motors.
Then there is wasted spark or COP.
If you have it run it, the only real downside is an additional layer of complexity and point of failure.
Never had a problem with one yet, myself, nor have any of the customers cars I've installed them on.
The main problem I have with a cranktrigger setup over a distributor setup is the engine needs to rotate as much as two revolutions before the computer starts sending spark. This can be the difference between starting with a weak battery, and walking. Or being able to bump-start the car while still rolling after stalling it.
I asked Kurt Busch once a few years ago why there were 2 MSD6a's in his car. I was poking my head in his car lookin' at stuff. He said it was so that they could have 2 different rev limiters and switch between them when the crew chief told him. 'Course, he was just a kid then.
I wonder if that is how they were doing traction control. If they knew about what their RPM coming out of a corner would be, it would be easy to tune how it came in.
There was an article about traction control cheating in one of the circle track magazines 10-15 years ago, very interesting. They wouldn't use wires, just conductive tape pressed into inconspicuous spots. The one thing they didn't explain was the actual mechanism for cutting spark.
Dr. Hess wrote: I asked Kurt Busch once a few years ago why there were 2 MSD6a's in his car. I was poking my head in his car lookin' at stuff. He said it was so that they could have 2 different rev limiters and switch between them when the crew chief told him. 'Course, he was just a kid then.
That wasn't the reason we did it but it was an added benefit. They would eventual fail from the vibrations so there was always a back up. Once you have to of them it's easy to have a higher chip or no chip at all for when you need a bit more speed and aren't worried about the engine coming apart.
Okay, I've done some reading through the manuals and it seems the best method is to use LS coils. The MS2V3.0 can trigger them directly. The MS needs a rpm signal which would be provided by the hall effect sensor and crank mounted trigger wheel.
Am I getting things right now?
That's pretty much it.
Bear in mind the "RPM signal" is also a position signal, the computer needs to know which cylinder is firing next. If you want coil on plug, you need to have a cam sensor also. Or a missing tooth trigger wheel driven off of the distributor instead of a crank trigger, which is not so good because it introduces gear rattle error, but it does work and a lot of OEMs did it that way.
Can't I use a 36-1 trigger wheel on the crank with a Hall Effect sensor and get wasted COP? If I'm reading the manual correctly that will control everything except straight COP and Sequential without the need for a cam sensor....?
redvalkyrie wrote: Can't I use a 36-1 trigger wheel on the crank with a Hall Effect sensor and get wasted COP? If I'm reading the manual correctly that will control everything except straight COP and Sequential without the need for a cam sensor....?
Yes, that's one available option.
MadScientistMatt wrote:redvalkyrie wrote: Can't I use a 36-1 trigger wheel on the crank with a Hall Effect sensor and get wasted COP? If I'm reading the manual correctly that will control everything except straight COP and Sequential without the need for a cam sensor....?Yes, that's one available option.
Same setup my engine's running.
Great. I read that you need to tie the coils together in pairs via the trigger wire. What's the best strategy for that?
I really appreciate the help guys.
redvalkyrie wrote: Great. I read that you need to tie the coils together in pairs via the trigger wire. What's the best strategy for that? I really appreciate the help guys.
Don't need to but you can. I'd think the best strategy would be to run them off individual coil drivers so that if a coil driver fails, you only lose one cylinder.
If you run CoP, you can gang 2 together so it runs waste spark. That way, you only need to use 2 channels, not 4 to drive the ignition. Note that with a CoP or the Camry coil pack option (Camry/Rolla coil packs have drivers built in), you don't need separate giant coil driver transistors. You can run them off a 2n2222 from the front panel light channels.
I don't recommend running the ls coils in waste pairs. I have had all three kinds hit protection mode (sparks early) from heat if run too long that way. If the motor is low revs and only for drag racing it may be ok but its not my first choice. Add a cam trigger and run them in cop mode or use low dwell (and lose the big spark).
Most modern Toyota coils have a very low dwell time, no trouble from mine at 8krpm+ yet.
Most coils (other than LS) have pretty low dwell time, but the spark energy is much lower. I usually use stock pencil coils unless I am shooting for more than 200hp/hole.
Is there any reason I can't powder coat the trigger wheel? They all come not coated...didn't know if there was a reason for this. Magnets still stick through PC...I don't see a problem unless the hall effect sensor is that sensitive?
Shouldn't cause a problem, many come painted or electroplated.
Cool. I have a 36-1 trigger wheel on the way with a hall effect sensor and four COPs that were recommended by Gameboy.
I've also got a completely new throttle linkage I need to assemble. Doing twin IDFs is tricky. Twin DCOEs are a breeze and plenty of linkage kits exist for that type of setup. However, the only linkage kits available for twin IDFs are VW and Porsche based...
Big thanks to Gameboy for documenting his build and answering my questions. And thanks to everyone else. I'm sure I'll be needing more help soon.
I'm researching to do a similar project, and I'd love to get an update on how all this worked out. I want to do programmable 3D ignition on my 74 Alfa running Dell'orto carbs.
Thanks - Cris
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