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emsvitil
Supercharged
Joined: 12 May 2005
Posts: 4720
Location: So California
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Post subject:
(Fri Nov 16, 2007 1:23 pm)
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I believe the mopar ignition boxes have an rpm rating.....
This rating is for a V8.
Since a 6 cylinder has less sparks per revolution, multiple the rpm rating by 1.3333 to get the equivalent rating for the 6 cylinder....
(i.e. you don't need the more expensive high rpm module  )_________________ Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes
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SlantSixDan
Board Sponsor & Contributor
Joined: 31 Oct 2002
Posts: 21883
Location: North America
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Post subject:
(Sat Nov 17, 2007 11:36 am)
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| Aggressive Ted wrote: | | If wanted to run a test between both the stock MOPAR System and the HEI conversion, what would be the best HEI module and part# to buy? |
Kinda depends how you want to set it up. The more I think about it, the more I like this setup, which has a module w/heatsink, a matched coil, and Weatherpak connectors all in one unit. The "E-core" coil was incorporated into the HEI system not so much because of its compact packaging, but because it offers specific functional benefits. These are described in detail in the lengthy SAE paper on HEI, which I have in paper (not electronic) form. E-core coils work also with Mopar electronic ignition, BTW.
But if you're just after the regular "put an HEI module on the inner fender and use an MSD Blaster coil" type of upgrade, you could run a NAPA Echlin TP-45, ACDelco D-1906, or Standard-Bluestreak LX-301 module._________________ 一期一会
By birth & parentage: US citizen, 2nd class
By choice: Canadian citizen, 1st class
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sandy in BC
Board Sponsor & SL6 Racer
Joined: 08 Nov 2002
Posts: 4603
Location: Burton BC canada
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Post subject:
(Sat Nov 17, 2007 2:35 pm)
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I have to confess to a period of my life where I played Chev 6.
230s 250s and 292s....
The single greatest improvement I have ever seen from the factory is from GM points ignition to HEI.
I used to run a 1981 Chev 250 2bbl with factory split exhaust and a 120 hp rating. The carb was 1/2 a Rochester Q-jet.
This six had a separate HEI coil like the EFI SBCs. The cool part is it is easy to mount....you can use the stock connectors and it is all about big spark for a 6. They are rock solid dependable. The coil itself is rather large.
I think Joshie is onto this one as well...... |
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SlantSixDan
Board Sponsor & Contributor
Joined: 31 Oct 2002
Posts: 21883
Location: North America
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(Sat Nov 17, 2007 2:58 pm)
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There are interesting reasons why GM spent so much money and effort developing a really, really good ignition system at a time when virtually everything else they were engineering was utter garbage._________________ 一期一会
By birth & parentage: US citizen, 2nd class
By choice: Canadian citizen, 1st class
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emsvitil
Supercharged
Joined: 12 May 2005
Posts: 4720
Location: So California
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Post subject:
(Sat Nov 17, 2007 3:22 pm)
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| SlantSixDan wrote: | | There are interesting reasons why GM spent so much money and effort developing a really, really good ignition system at a time when virtually everything else they were engineering was utter garbage. |
Spill.......... _________________ Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes
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70Dart
4 BBL ''Hyper-Pak''
Joined: 21 Aug 2007
Posts: 49
Location: Antelope Valley, California, USA
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Post subject:
(Sun Nov 18, 2007 9:37 pm)
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| I'm going with HEI, and it seems thats the best way to go.
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SlantSixDan
Board Sponsor & Contributor
Joined: 31 Oct 2002
Posts: 21883
Location: North America
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Post subject:
(Mon Nov 19, 2007 4:47 pm)
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| emsvitil wrote: | | SlantSixDan wrote: | | There are interesting reasons why GM spent so much money and effort developing a really, really good ignition system at a time when virtually everything else they were engineering was utter garbage. |
Spill... |
The two biggest US automakers — GM and Ford — screwed up almost everything they touched when serious emission regulations were phased in starting in the early 1970s. They futzed around with ridiculous Rube Goldbergery and persnickety Frankencarburetors, couldn't make a catalytic converter without creating asinine levels of exhaust restriction, and just generally behaved as though emission control were a silly passing fad not worth putting much serious thought or effort into.
But GM in particular did devise seriously good electronic ignition systems, some of which can convincingly be described as the best of their type in the world. Why? Well, because it was less costly to design really strong ignition systems than it was to rework half-baked fuel systems and stone-age combustion chambers and add-on widgets, and the improved combustion resulting from really good ignition systems compensated for a multitude of sins in those other places.
The reason GM worked (and spent) especially particularly hard to have a super-duper ignition system was because their catalytic converter development program was cursed. Or maybe it was just riddled with incompetence. Or perhaps — just perhaps! — given the connection between GM and Ethyl Corp (who made most of the Tetraethyl Lead used in gasoline), the GM catalyst program's primary purpose was to serve as an illustrative example for GM to point to of the stupidity, costly waste, foolishness, pointlessness, exorbitant expense of the very idea of cleaning up auto exhaust emissions in general, and of the unworkability of catalytic exhaust treatment in specific. Most of their test catalysts worked poorly, had short lives, created significant driveability problems, started fires, and otherwise were NFG.
Eventually they figured out that the 1975 emission standards were going to be the 1975 emission standards no matter how big a temper tantrum GM threw about it and no matter how hard GM dragged their feet, so they launched their pellet-type converters in the 1975 model year. A large advertising campaign trumpeted the fact that a '75 GM car running on unleaded cost less to operate than a comparable '74 running on leaded, in improved fuel mileage (because the engine didn't have to be strangulation-tuned so much to meet the tailpipe standard, with the catalyst cleaning up the trash in the exhaust), and in reduced maintenance (because spark plugs lasted longer with no-lead fuel).
PR song-and-dance aside, these pellet-type converters were terrible. They cleaned up the exhaust, but they were backpressure monsters. They consisted of a chamber enclosed on top and bottom with expanded metal mesh. Within this chamber was a tightly-packed bed of spherical little ceramic beads coated with catalytic materials. The exhaust entered the converter, was routed to the bottom, forced its way through the lower metal mesh, through the bed of packed beads, through the upper metal mesh to the top of the converter, and then was routed to the converter outlet. The hissing exhaust of a floored vehicle so equipped was external evidence of how restrictive these converters were. And they always ran on the ragged edge of overheat, especially because fuel management was left up to a plain ol' carburetor, which gave a more or less random mixture just as likely to be too rich as too lean...especially if the engine were out of tune, the air filter were dirty, the car were driven on a day ending in the letter "y", etc.
So "confident" (hah!) were the GM engineers in the integrity of their converter that they specified spark arrestors on the tailpipes of station wagons, trucks, and vans...basically any vehicle likely to see heavy usage. The spark arrestor was a perforated metal sheet a few inches in from the tip of the tailpipe. Its job was to catch catalyst beads once the metal mesh in the converter got too hot, lost its temper, softened and started allowing beads to blow out with the exhaust. That way the hot beads wouldn't start fires. Fine quality GM "Mark of Excrement" engineering, you betchya. 
The last line of defence against converter meltdown was a super-strong ignition system that maximised the chance of lighting each and every cylinder, each and every time. That system was HEI.
And now you know...the ressssssssst of the story._________________ 一期一会
By birth & parentage: US citizen, 2nd class
By choice: Canadian citizen, 1st class
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Aggressive Ted
Supercharged
Joined: 15 Jan 2007
Posts: 3301
Location: Black Diamond, WA
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Post subject:
Why is the HEI better.
(Mon Nov 19, 2007 7:51 pm)
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Dan,
That is quite an answer to my question. You have convinced me to start collecting parts and test it. Thanks for the part numbers too.
Thanks!  |
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SlantSixDan
Board Sponsor & Contributor
Joined: 31 Oct 2002
Posts: 21883
Location: North America
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Post subject:
(Sat May 03, 2008 8:59 pm)
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| SlantSixDan wrote: | | Aggressive Ted wrote: | | If wanted to run a test between both the stock MOPAR System and the HEI conversion, what would be the best HEI module and part# to buy? |
Kinda depends how you want to set it up. The more I think about it, the more I like this setup, which has a module w/heatsink, a matched coil, and Weatherpak connectors (another really good piece of GM engineering) all in one unit. The "E-core" coil was incorporated into the HEI system not so much because of its compact packaging, but because it offers specific functional benefits. These are described in detail in the lengthy SAE paper on HEI, which I have in paper (not electronic) form. E-core coils work also with Mopar electronic ignition, BTW.
But if you're just after the regular "put an HEI module on the inner fender and use an MSD Blaster coil" type of upgrade, you could run a NAPA Echlin TP-45, ACDelco D-1906, or Standard-Bluestreak LX-301 module. |
_________________ 一期一会
By birth & parentage: US citizen, 2nd class
By choice: Canadian citizen, 1st class
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