MSD Coil on plugs vs Factory OEM

Don't waste your money.

This is pure speculation based upon my understanding and research into coil on plug technology, and not from first hand experience.

If we look at a traditional ignition system we have a single coil firing 8 cylinders. At 6000 RPM the coil has to fire 3000 times per minute per cylinder for a total 24,000 times per minute or 400 times per second. As a dwell times (the time the coil has to charge before firing again) fall to .0025 of a second the quality of the coil becomes more important. Further, traditional coils only operate at 9 volts!

The modern hemi utilizes a coil on plug arrangement in which each coil only fires a single cylinder (or in wasted spark two cylinders). At 6000 RPM a coil only has to fire 3000 to 6000 times per minute vs 24,000 times. Thus, the amount of dwell time available increase from .0025 seconds to .02 seconds. Even in wasted spark mode the coil has four times the available dwell times.

To put this all in perspective hot rod did a test with a supercharger / turbo charged Chevy LS motor with 20 Lbs of boost. Only when the motor went over 20 lbs of boost did they start to run into problems with the stock LS coils.

Also the guys at megasquirt did some testing on the LS style coils and found them to be flame throwers. Very powerful, and very cheap.

I'd consider the Hemi coils to be similar in power output to the LS coils. Hotrod has done several hemi engine tests with between 500 and 1000 HP and has always used stock coils.

Unless you are running extremely high boost (over 20 lbs) or a ridiculous amount of NOS, I'd spend your money elsewhere, for example, you could donate the money to the joe-dokes let's finish this hemi project fund. ;)

Best of Luck

Regards,

Joe Dokes