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post #14 of (permalink) Old 09-08-2005, 09:04 PM
Junk Yard Genius
 
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Re: TFI and HEI what\'s the difference?

OlllllllOCJ / Dale, LIGHTEN UP!
This ain't pIRATE 4x4, we're all friends here... [img]/ubbthreads/images/graemlins/blush.gif[/img]

BTW, Good search info in your post! That just about covers everything!
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Do you know how many times I had to post the Original Ignition upgrade when I first started out here five or six years ago?
Or how may times I've been asked the same 4 or 5 questions?
This is a new experance and a BIG STEP for some of these guys just starting out...

When I first started out here...
Everyone was spending $500 (or more!) bucks on Jacobs junk, getting little or no customer service and having to pay for what should have been warranty work...
(in Jacob's defense, they are getting better about things since the company changed hands...)

Or the dreaded DUI HEI...
There is a piss away $400 of your favorite dollars!

All just so they could have larger caps, better plug wires, ect...
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It was so difficult to get anyone to believe that just a few dollars worth of off the shelf parts could make the stock Jeep ignition run with the high dollar bunch...

And the fact that it was all bolt on, with no modification...
That made a lot of people think it was too go to be true...
No one really accepted it until someone put together the parts and started selling it online...
Once you hang a 5X price tag on it, they started believing it...
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What I still don't understand is the big move to install a HEI module.
With the cap, rotor, plug wires and coil upgrade, the factory DuraSpark ignition is getting the job done as reliably as can be expected, and (arguably) better than most ignitions would.

TFI, HEI, DuraSpark, Hy Fire are all STILL INDUCTIVE IGNITIONS.
It doesn't matter which inductive ignition you use, it's still a 12 volt inductive ignition...
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12 volt inductive ignitions give you ONE (1.0) chances to fire the cylinder, and if the input voltage to the coil is low, or the fuel mixture is overly rich/lean, or not atomized properly, or if the piston/rings aren't warm, expanded and optimizing compression, or if there is excessive moisture in the air (cold weather/fog/rain) or if the plugs are gaped even a little oversize, or if your engine is getting on in years and has a little oil fouling in the cylinder...
ECT. ECT. ECT. ECT.....
THAT INDUCTIVE IGNITION ISN'T GETTING THE JOB DONE RELIABLY, PERIOD.
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The best deal going on modules is the MSD 6 series module.
It's a True Capacitive Discharge ignition, and it just blows the inductive ignitions off in the weeds!

I know there are several here that for what ever reason don't like MSD...
But the fact of the matter is, MSD delivers 100% to 1,000% increases in useable spark energies, and does it in the lower operating RPM ranges, from idle on...

More amperage, more voltage, more spark duration, the three areas of spark energy that regular factory ignitions can't hold a candle too...
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Voltage:
More voltage means you can fire the plug with a wider gap.
Fire the plug with carbon, liquid fuel or water/oil fouling.
Fire the plug with dense moisture content (foggy days or with water injection).
Fire the plug with todays extra lean fuel ratios.

Amperage:
More Amperage means a 'Hotter' or 'Richer' spark.
That means the spark can burn away fouling.
Ignite lean fuel mixtures.
Ignite overly rich or poorly atomized fuel/air mixtures.

Duration:
MSD delivers around 1,000% more duration of spark, the actual time the spark lasts in the gap of the plug.
MSD does this by firing the plug several times very quickly with a very hot spark, making sure your cylinder actually fires and produces power, instead of being a dead player and a burden on the rest of the engine.

ANY output from the cylinder is preferable to being a drag on power for the rest of the cylinders...
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Once you do the cap, rotor, plug wire, coil upgrades...

If you just want to 'Tinker' with your ignition system, by all means, do the HEI module.
You will gain experience, confidence and you will learn something.
You may also be the First, or maybe the ONLY guy in your group with that particular modification...
And for about $20 for the module, and a few bucks in wire and terminal ends, it's a pretty good way to learn about ignitions.
(Don't forget to supply that module with a power relay and some 10 AWG wire!)

If your Jeep is running fine by your standards, and you don't see any reason to 'Tinker' further, then by all means, STOP!
If it makes *YOU* happy, then that's all it has to do!

If you want increased horse power in all ranges, increased torque and pulling power, increased fuel mileage, cleaner emissions (a real biggie for some of you!), and a cleaner running engine, you may want to consider a $150 MSD module...
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