Getting rid of the cas and coil pack
in my adventure of turbo'ing my Miata I've come to realize the stock coil pack isn't helping me much. to get rid of it, the simple solution would be coil on plugs, correct?
as for the cas, would a crank trigger setup, say like for the NB, replace it? or am I missing something? |
Nothing like this has been done before. You'll be breaking new ground, and I'm sure a lot of us would be interested in your results. Record your progress and take lots of pics for us.
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For some reason, I'm feeling generous...
Originally Posted by itsMikey
(Post 1313539)
in my adventure of turbo'ing my Miata I've come to realize the stock coil pack isn't helping me much. to get rid of it, the simple solution would be coil on plugs, correct?
Originally Posted by itsMikey
(Post 1313539)
as for the cas, would a crank trigger setup, say like for the NB, replace it? or am I missing something?
The NB crankwheel won't help you at all unless you are also running an NB head, since the NB cam sensor needs to accompany the NB crank sensor in order for any ECU to be able to decode the signal. If you're using a stock ECU, forget it. Unless you want to design, build and program a custom microcontroller so simulate the output of an NA CAS based on some other pattern, it ain't gonna happen. No off-the-shelf solutions here. If you're using an aftermarket ECU, then there are a bunch of options. Several companies make crankwheels that fit the Miata, and Mazda even used a 36-1 wheel on certain engines (there's a thread about it in the ECU section here) which can be used. |
Originally Posted by Joe Perez
(Post 1314240)
The NB crankwheel won't help you at all unless you are also running an NB head, since the NB cam sensor needs to accompany the NB crank sensor in order for any ECU to be able to decode the signal.
If you're using a stock ECU, forget it. Unless you want to design, build and program a custom microcontroller so simulate the output of an NA CAS based on some other pattern, it ain't gonna happen. No off-the-shelf solutions here. If you're using an aftermarket ECU, then there are a bunch of options. Several companies make crankwheels that fit the Miata, and Mazda even used a 36-1 wheel on certain engines (there's a thread about it in the ECU section here) which can be used. |
Originally Posted by aidandj
(Post 1314245)
Can B series engines run off just a crank trigger? Batch fuel and spark? Or sequential.
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Interesting.
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Originally Posted by itsMikey
(Post 1313539)
in my adventure of turbo'ing my Miata I've come to realize the stock coil pack isn't helping me much.
as for the cas, would a crank trigger setup, say like for the NB, replace it? or am I missing something? |
Originally Posted by aidandj
(Post 1314250)
Interesting.
In order to run on only one trigger input (eg: a crankwheel) the ECU has to be able to determine the absolute position of the crankshaft. It needs to be able to tell when #1 is at TDC, and when it's at BDC. A crankwheel with all evenly-spaced teeth gives you an ambiguous indication in this regard. Taking the stock NB wheel as an example, it'll tell you that some piston is at TDC, but not which one. In most present-day applications, a cam sensor is used to give a pulse which tells the ECU "the next time you see an indication from the crankwheel that a piston is at TDC, that'll be the #1 piston, and it'll be at TDC on the beginning of the intake cycle," or something like that. You can get away with not using a cam sensor if you're willing to run wasted spark and batch-injection. You do this with a missing-tooth wheel. When the ECU sees the missing tooth pass by it knows "#1 is approaching TDC." It doesn't have enough information to know whether that's #1TDC on the exhaust/intake transition, or #1 TDC on the compression/ignition transition, but this doesn't matter for batch-injection and wasted-spark, since it's going to do the same thing (fire the plug and open the injectors) either way. |
Just interesting to me. Learn something every day. I figured it would have to be a missing tooth wheel.
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Maybe we can dredge more info out of this thread.
You know, in order to help the OP hah. How far can the na6 ignition system go? On a stock piston vvt motor (with crank and cam sensors), I'm at 150kpa with a base pressure of 85kpa and have seen as low as 11.0:1 afr's during tuning at full tilt in 3rd/4th. No issues.... Dwell is at whatever the ancient diyautotune recommendation was for the na6. |
Originally Posted by leboeuf
(Post 1314276)
How far can the na6 ignition system go?
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Originally Posted by leboeuf
(Post 1314276)
How far can the na6 ignition system go?
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On my '99, when I had the leaky waste-gate actuator, I got to 12psi at 7K RPM, with no trouble on the stock coils and .036" (IIRC) gaps. I want to go to COP's simply to get the coil packs out of the way of the coolant re-route, and so that I don't have to replace the expensive buggers at an in-opportune time (in other words, for reliability). Sequential spark should be a plus as well, but I'm not sure on how much.
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