Gruntguru,
The HEI module does NOT become a 'resistor', according to GM.
From the GM description of HEI operation. "A current limiting cct was added to the HEI module to limit primary current to 5.5 amps, rather than using resistance. This feature allows the electronic devices to operate at their maximum value".
Crane xr-1 point to electronic module
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Re: Crane xr-1 point to electronic module
Rather than using any *external* resistance at least.
With HEI the switching transistor in the module applies the full 12 volts to the coil until it hits 5.5 amps / 7 amps / whatever, then the transistor *partially* switches off so instead of maybe 1 volt drop across it while the current is running up, maybe 6 or 7 volts is now dropped across the transistor, whatever is needed to hold the current at the assigned limit until the transistor is told to suddenly turn completely off and the spark happens. So the transistor does maybe sorta kinda become a resistor momentarily. Technically speaking it becomes a constant current sink because the amount of amps it maintains doesn't vary appreciably with any variance of the voltage dropped across it like a real resistor would.
With HEI the switching transistor in the module applies the full 12 volts to the coil until it hits 5.5 amps / 7 amps / whatever, then the transistor *partially* switches off so instead of maybe 1 volt drop across it while the current is running up, maybe 6 or 7 volts is now dropped across the transistor, whatever is needed to hold the current at the assigned limit until the transistor is told to suddenly turn completely off and the spark happens. So the transistor does maybe sorta kinda become a resistor momentarily. Technically speaking it becomes a constant current sink because the amount of amps it maintains doesn't vary appreciably with any variance of the voltage dropped across it like a real resistor would.
Re: Crane xr-1 point to electronic module
A trans-sistor can be modeled as a potentiometer ,it does vary its resistance between the collector and emitter . just thinkingCirclotron wrote: ↑Mon May 21, 2018 7:26 am Rather than using any *external* resistance at least.
With HEI the switching transistor in the module applies the full 12 volts to the coil until it hits 5.5 amps / 7 amps / whatever, then the transistor *partially* switches off so instead of maybe 1 volt drop across it while the current is running up, maybe 6 or 7 volts is now dropped across the transistor, whatever is needed to hold the current at the assigned limit until the transistor is told to suddenly turn completely off and the spark happens. So the transistor does maybe sorta kinda become a resistor momentarily. Technically speaking it becomes a constant current sink because the amount of amps it maintains doesn't vary appreciably with any variance of the voltage dropped across it like a real resistor would.
A good test is worth a thousand opinions.
Smokey
Smokey
Re: Crane xr-1 point to electronic module
Back to the subject of using a HEI external coil. I was wanting to know if the crane xr-1 module would fire the coil. Tuner said you could if you used enough resisitance to get 3 ohms,others said no so as to who is correct seems to be undetermed. I dont want to fry the xr-1 module. The coil I have is supposed to be a ps-20 black coil which is a 42,000 volt coil which is in the same strengh as a HEI .When I first got it it would jump a HEI tester. It got to running a little rough so thats when I tested it and the spark no longer jumped a HEI gap. To me it looked like a weak coil so I put the HEI distributer in and the spark was good ,engine ran good.BUT the distributer hits the hood and was messing up the wires. The points distributer is 2 inchs shorter so back to it .TodayI tested the system using a used coil( cannister style)I had on the shelf,darned if I know where it came from or the brand didnt know I had it.I put the resister in line before the coil a 1.7 ohm.hooked up power and grounds and turned it by hand and now the spark jumps a HEI tester easly with a strong white snap of current.So now I have a good spark and If it dont rain on me tomorrtow I will install it tomorrow and see how it runs.
The reasoning for the HEI coil use was because I have 3 of them verses buying another coil.I did test the ohms on the hei coil and it seemes to be .003 ohms so I would have to get a resister of 2.9 or so ohms. Still dont know if I could use a HEI coil with the Crane XR-1 module since everyone is divided on if you can or cant. I got my ignition fixed so now it doesnt matter but I still wonder as to if you can without burning the module up.
I appreciate all the replys and thoughts everyone had. Thank all of you for you time .
Richard richie49
The reasoning for the HEI coil use was because I have 3 of them verses buying another coil.I did test the ohms on the hei coil and it seemes to be .003 ohms so I would have to get a resister of 2.9 or so ohms. Still dont know if I could use a HEI coil with the Crane XR-1 module since everyone is divided on if you can or cant. I got my ignition fixed so now it doesnt matter but I still wonder as to if you can without burning the module up.
I appreciate all the replys and thoughts everyone had. Thank all of you for you time .
Richard richie49
Re: Crane xr-1 point to electronic module
Nobody said you "can't" use an hei coil with that, you can.
It would be half or less the spark energy verses using the appropriate coil. With small enough plug gaps....it should work.... well enough to drive to the store and buy the right coil.
To know what the right coil is, we need to know how many cylinders the engine has, and also a rough idea what RPMs it runs.
It would be half or less the spark energy verses using the appropriate coil. With small enough plug gaps....it should work.... well enough to drive to the store and buy the right coil.
To know what the right coil is, we need to know how many cylinders the engine has, and also a rough idea what RPMs it runs.
Re: Crane xr-1 point to electronic module
Coils are either designed to work with a resistor, or without [ such as HEI ]. They also should be used with the supply voltage they are designed for. So no 6v coils with 12v & vice versa. Resistor values vary so the correct resistor [ as specified by the coil maker ] should be used with the coil.