going to dyno, where to pull RPM signal from?
02-01-04, 06:57 AM
#26
HAILERS, I hope you hooked up the Blue wire coming off the Crane-Cams HI-6 Ignition Box. I made that mistake before as a few others...
Just In case you didn't know, The Blue Wire, when hooked to 12v, sets the CDI Multi Spark duration. It also tells the CDI unit how many revs or Ignition pulses there are. We obviously do not have cylinders.
But we do have a certain amount of Ignition pulses In two engine rpm (defines one complete cycle in a 4 stroke piston motor) and this Is what the Crane-Cams Ignition Box needs to measure.
If It does not know how many Ignition pulses occurs - i.e Blue Wire NOT hooked up, It'll assume it is a 8 cylinder engine, this will mean that It will multi-spark the Ignition up to 6000rpm, as opposed to 3000rpm.
Thats not good. It also means that the duration of the multi-sparking will be double the length of what it should be, as this value tapers off as you reach 3000rpm to a point where the unit can only provide one Spark In any given time. It will mean that the unit Is working twice as hard. And when Ignition needs to be retarted (although, you said It's on your NA), watch out If the Blue Wire Isn't hooked up.
Just In case you didn't know, The Blue Wire, when hooked to 12v, sets the CDI Multi Spark duration. It also tells the CDI unit how many revs or Ignition pulses there are. We obviously do not have cylinders.
But we do have a certain amount of Ignition pulses In two engine rpm (defines one complete cycle in a 4 stroke piston motor) and this Is what the Crane-Cams Ignition Box needs to measure.If It does not know how many Ignition pulses occurs - i.e Blue Wire NOT hooked up, It'll assume it is a 8 cylinder engine, this will mean that It will multi-spark the Ignition up to 6000rpm, as opposed to 3000rpm.
Thats not good. It also means that the duration of the multi-sparking will be double the length of what it should be, as this value tapers off as you reach 3000rpm to a point where the unit can only provide one Spark In any given time. It will mean that the unit Is working twice as hard. And when Ignition needs to be retarted (although, you said It's on your NA), watch out If the Blue Wire Isn't hooked up.
Last edited by silverrotor; 02-01-04 at 07:02 AM.
02-01-04, 09:16 AM
#27
HAILERS
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Nope. They're on the two turbo cars and I have the blue wire connected to a switched 12v. It's the 86na that I ain't a gonna spend money on. But I'm gonna check the bullets on that car because it has no big buck, brand new Crane to connect to. Thanks for the heads up though. Its ground for the blue for a six, nothing for a eight, and switched 12v for a four or rotary.
02-01-04, 11:15 AM
#28
No problem. On Turbo FC's, the consequences would be more severe. It will mean that the unit Is working twice as hard, as Is normaly required and depending on Ignition timing (retard with boost at 5 to 6k prm) could be firing a spark (as It will still be in multi-spark mode until 6k if no Blue Wire Is hooked up) once the chamber has swept past the leading Spark Plug hole.
02-01-04, 01:08 PM
#29
I'm a boost creep...
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Originally posted by HAILERS
[BNay, nay NewZealander, not I. I specialize in airpump superchargers, not ignition issues.[/B]
[BNay, nay NewZealander, not I. I specialize in airpump superchargers, not ignition issues.[/B]
It was someone who had half a clue about these cars, so I immediately thought of you. 
Originally posted by White_FC
Or maybe it was that sheep over there behind THAT tree??
Or maybe it was that sheep over there behind THAT tree??
Yeah, an oscilloscope is what we need. Or, perhaps someone could just stick a regular tacho on both coils.
02-01-04, 02:24 PM
#32
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Read this: https://www.rx7club.com/showthread.p...ometer+install
and Scott's reply. Twice the rpms on the front bullet. I can do the same thing with a inductive clamp connected to my voltmeter and the meter on rpms. Clamp on a LEAD sparkplug wire and you'll see approx 1500 rpm. Put the clamp on a trail plug wire and you'll see....750rpms. Now on to a serious discussion about the dual airpump supercharger with a serpentine belt ..........
and Scott's reply. Twice the rpms on the front bullet. I can do the same thing with a inductive clamp connected to my voltmeter and the meter on rpms. Clamp on a LEAD sparkplug wire and you'll see approx 1500 rpm. Put the clamp on a trail plug wire and you'll see....750rpms. Now on to a serious discussion about the dual airpump supercharger with a serpentine belt ..........
02-01-04, 02:28 PM
#33
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while they were setting up on my car one of the workers was looking for a wire to connect to, to get a signal. he asked the head guy. I stepped in and told him he where he could get it. he stated that, pulling it from there wouldn't really work. what I believe they did was pull from both the leading and trailing coil. he said that mazdas are weird and they had to figure out what rpm they were at. he told one guy that he was gonna rev it at 2k so they could figure out what the pulses were . I don;t know if that makes any sense to you guys.
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