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02loftsmoor |
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#1
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Senior Member ![]() ![]() ![]() Group: Members Posts: 577 Joined: 26-June 11 From: Ft. Worth TX Member No.: 13,243 Region Association: Southwest Region ![]() ![]() |
I'm check on going with distributor-less ignition system, some pointers please
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stugray |
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#2
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Advanced Member ![]() ![]() ![]() ![]() Group: Members Posts: 3,825 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None ![]() |
The simple MSDs require a tach signal that represents each cylinder firing, and it can be a nice clean signal like from a unilite optical pickup, a hall effect, or a noisy signal from a real coil/points.
My setup uses the mallory optical pickup straight to the MSD. It is a perfectly clean looking 12VDC square wave. You could split that signal to two MSDs and they would both fire simultaneously. Now we just need to slow down the output for one of the MSDs and you have staggered firing. So since the MSD can accept a nice clean 12VDC signal, I would just use two Mosfet "modules" for $5ea. to convert the Ard 5VDC IO to a 12VDC square wave. And now that I thought about it, you could have either a second rotating pickup, or just a 5th "tooth" in the trigger wheel to determine crank position (TDC) You could use that and provide a FI trigger signal to either a stock FI ECU, or a Megasquirt. An encoder on the distributor is essentially "crank fired" anyway ( but you know that) As far as overheating, if you are using the distributor to drive the COP style of MSD, then there is no "distributing" being done at the distributor, so it wont get very hot. A fan on the distributor drive shaft could push air through the cap. The operating temperature of the Atmega (+85C) is the same as the Renesas SH series CPUs in my BRZ, so I think it should be ok. |
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Lo-Fi Version | Time is now: 28th June 2024 - 02:51 PM |
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