GM HEI vs. unilite
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Cruising
Joined: Mar 2007
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GM HEI vs. unilite
I'm actually on the verge of swaping from a GM HEI (in cap coil of a 78) to a mallory 57 series Magnetic Breakerless Ignition. I'm running a hotter coil than the GM in cap but the general opinion seems to be that I'm going to loose some power and response. Does anyone know if I should expect to lose a considerable amount or could I gain some by running the hotter coil?
Le Mans Master
Joined: Dec 2006
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I'm actually on the verge of swaping from a GM HEI (in cap coil of a 78) to a mallory 57 series Magnetic Breakerless Ignition. I'm running a hotter coil than the GM in cap but the general opinion seems to be that I'm going to loose some power and response. Does anyone know if I should expect to lose a considerable amount or could I gain some by running the hotter coil?
Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
The "hotter coil" won't gain you anything unless you're running compression levels and rpm so high that you're on the verge of extinguishing the spark.
The type of ignition system you run, whether it be stock points, stock HEI, or one of the aftermarket capacitive discharge systems triggered opticially or magnetically is irrelevant as long as you're getting adequate spark to fire the plugs at the compression and rpm you are running. What is far more important is the timing curve you set up in the system you are running. The timing curve will determine the power and throttle response you get - not the type of trigger device or how "hot" the coil is. I've shown many times that a properly curved old-style points system with a stock coil will grossly out-perform a fancy capacitive discharge system with a "hot" coil if the curve in the aftermarket system is not set up right.
Spend time tuning what you have. The gains will be much more than by simply replacing with other style components.
The type of ignition system you run, whether it be stock points, stock HEI, or one of the aftermarket capacitive discharge systems triggered opticially or magnetically is irrelevant as long as you're getting adequate spark to fire the plugs at the compression and rpm you are running. What is far more important is the timing curve you set up in the system you are running. The timing curve will determine the power and throttle response you get - not the type of trigger device or how "hot" the coil is. I've shown many times that a properly curved old-style points system with a stock coil will grossly out-perform a fancy capacitive discharge system with a "hot" coil if the curve in the aftermarket system is not set up right.
Spend time tuning what you have. The gains will be much more than by simply replacing with other style components.
