HEI in Mopar ECU casing

cuda66273 said
Does anyone here know what the Voltage output requirements are to trigger any of the more than 30 different "GM" 4 pin modules? Does anyone know what the output of the at least 20 different Mopar Magnetic Pick-Up's are? Why would anyone go through all this and not even know what the output of the module is, the trigger signal requirements or the RPM limits?
Just because it's called a "HEI" doesn't make it work any better when combined with all the wrong components.

We've tested probably 10,000 GM HEI modules from manufacturers in probably 20 countries over 40 years, some work OK and most work no better than a Mopar stock ECU. Some of the Performance Modules are better but sure not the end all.

The correct coil for the module is extremely important, the voltage signal and ambient tempuratures are critical.

Will they work and run the motor.... in most cases yes, but I can wire up a Golf Cart to run on a Mopar or GM module. Give me a Voltage Signal from a pick-up of somekind and a coil and I'll make it run. Mopar, Duraspark, GM HEI stock modules are all 1970's technology, it's 2013, we have color TV's and phones without wires.

"The Mopar system uses the positive temperature coefficient of the ballast resistor to regulate the primary coil current with changes in duty cycle (engine rpm). A simple, relatively reliable system for most daily drivers. The disadvantage with the ballast resistor is the slow response time of the resistor resulting in the field of the coil not being fully charged during sudden acceleration ie, a spark that may not be as hot as is possible with more modern systems. The GM HEI module is typically based upon a Motorola (now Freescale) MC3334 IC or equivalent. The MC3334 regulates coil current using an internal variable voltage reference. This internal variable voltage reference is able to respond much faster to changes in duty cycle resulting in a much hotter spark durring times of sudden acceleration and less destructive heating to the coil during low rpm operation. The MC3334 also imposes a 1 msec off time to ensure complete discharge of the coil field during a spark event. At very high rpms coil current is limited due to the slope of the coil's primary charging ramp time which is determined by VBatt and the primary impedance of the coil itself. Some good OEM coils are the Ford "E" core coils and the remote GM coil which is also an "E" core design. The MSD Blaster line of aftermarket coils are also very good coils. Don't be fooled by claims of HIGH VOLTAGE from the perveyors of coils. The voltage developed by the coil will only be as high as the break-over voltage of the plug firing, typically only a few thousand volts. When shopping for coils it is important to look for a coil with a high Joules rating and match the rpm range to your needs. If the coil manufacturer does not publish the joules rating of the coil, walk away and buy somewhere else. Don't use a race only coil on the street. It will just overheat and fail."

http://www.slantsix.org/forum/viewtopic.php?p=98527&highlight=#98527