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TuckerLudlow
Dodge Dakota
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9/12/2003
00:55:10
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 Subject: Larry - MSD Ignition?
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Message:
OK, I need an ignition engineer here.
Larry, I saw one of your posts re MSD ignitions, and went looking for the stuff at Summit Racing. While I was there looking for the MSD-6, I saw the MSD-5 which is described as being for those with no performance mods (no cams, intakes or carb mods). Mine is a bone stock 3.9, except for a K&N drop-in.
I laid the spec's for the MSD-5 and the MSD-6a side by side. Tabs and spaces get compressed out on this board apparently, so use the "bar" as the separator between the two. Here's what they show:
MSD-5 | MSD-6a
$83.95 | $149.95
+12 VDC | +10-18 VDC
6 amps | 5amps/5000RPM,10 amps/10,000RPM
20 degree crank rotation on both
140 millijoules/spark | 105-115 milljoules/spark
Volts output; 375 prim, | 460-480 primary,
40,000V secondary | 45,000V secondary
(What the hell is a millijoule? Is that a measurement of spark size? Is it like golf, with a lesser number being the better score?)
The MSD-6a spec's qualified the 45K, saying that you needed the Blaster coil and I just assume that the MSD-5 would also need it. I'd also assume wires, cap and rotor for both.
My question really is: why wouldn't I use the MSD-5 if I was looking for purely fuel economy as opposed to speed? According to the marketing stuff, it produces a "series of sparks" at engine speeds less than 3000rpm - wouldn't that assure a cleaner burn? Heck, MOST of my driving is under 3000rpm!
Larry or anybody?
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J and J Auto
GenII
9/12/2003
11:03:00
| RE: Larry - MSD Ignition?
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Message:
The 5 is a cheaper unit,
the 6a ia heaver and stronger than the 5
Go with the 6a
Capasitive Discharge, Multispark Unit
Yes it will hit 3 times at lower rpm drops to
2 times around 2000rpm and will go to a strong
long duration spark at 2800 3000 rpm
Gives you a cleaner burn
I am still playing with mine, I have the AP3923
gaped .060 and man she runs nice, I had been
running it at .050 seamd to be ok but a little
arc over on the plugs so I opend them up and it
made a big differance.
Here is a plug study before and after they
upgraded the ignition with a CD unit and a
better coil. I found there study very interesting
QUOTE
For example, we tested a 253 cu. in. V-6 engine, which was slightly modified, with the factory recommended .045" (1.14 mm) spark plug gap. With the stock ignition in place, it produced 168 horsepower. We installed platinum plugs gapped at the same .045" and the horsepower increased to 171. When we installed Split Fire plugs, the horsepower stayed at 171. With surface gap plugs, the horsepower rose to 172.5.
Next, we installed an Ultra Team (note CDC, a special coil and ignition wires package), reinstalling the original steel electrode plug gapped at .045" and the horsepower increased to 180.5. Keeping the gap a .045", we reinstalled all three sets of specialty plugs, recording an average 1.5 - 2 horsepower drop from the 180.5 recorded earlier with the steel electrode plugs. The reason for this power loss was that the specialty plugs required less arc-over voltage at the same gap; therefore, the peak spark power fell off.
Then we experimented with the plug gaps, continuing to use the Ultra Team With steel electrode plugs, the peak horsepower achieved was 186 at .063 gap. Split Fire plugs achieved 184 horse power, but required a .067" gap, causing concern about piston contact. The platinum plug peaked at just under 185 horsepower, with an optimum plug gap of .066" * The surface gap plugs were not re-tested as their gap is a fixed surface and cannot be increased. ""
millijoule is just a reading of electric how much goes to the coil to produce 40,000 volts with the
SS Blaster
Larry
J&J Auto
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TuckerLudlow
Dodge Dakota
JOIN HERE
9/12/2003
11:59:15
| RE: Larry - MSD Ignition?
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Message:
OK, next question. I see several units on eBay. There's some MSD-6AL's and a couple "Offroad" units (appear to be the same as the MSD-6AL with waterproofing). The MSD-6AL appears to be the same as the MSD-6a except a rev limiter is incorporated. AND, they're going for less $$$ than the MSD-6a's! Any reason not to go for one of them? I don't really need the rev limiter, but it won't hurt anything, I guess.
Again, I'm after mileage. Saw your post on the PVI thing, too. Looks interesting. How about another report in a month or so?
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Mark
Forum Moderator
9/12/2003
14:17:24
| RE: Larry - MSD Ignition?
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Message:
Larry, You use the autolite platinums? I was going to get those but wasnt sure how well they worked. I have my regular 3923's gapped to .040. The recommended gap for my year is .035 Is that the same as yours? If so I will try to gap them to .060 but that seems to be stretching it to me. It doesnt hurt to try though.
-Mark Hryckiewicz
1993 Sport RC SB 5.2L Auto
DodgeDakotas.com
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TuckerLudlow
Dodge Dakota
JOIN HERE
9/12/2003
16:35:12
| RE: Larry - MSD Ignition?
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Message:
Found it! One joule is the equivalent of one watt of power radiated or dissipated for one second. So it would appear that the higher number for millijoules would be the better one. Had to go to an electrical engineer I know to get the answer to this one. Webster's Online didn't have it.
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LaserGuy
Dodge Dakota
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9/12/2003
18:56:40
| RE: Larry - MSD Ignition?
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Correct: a millijoule is to a joule as a millmeter is to a meter. The more the better unless the energy is hitting you.
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J and J Auto
GenII
9/13/2003
10:27:41
| RE: Larry - MSD Ignition?
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Message:
Mark try .060 and see what happens
The MSD instructions and talking with MSD they
tell you to open them up .005 at a time untill
you lose performance than back off .005.
At .050 they were white, I pulled them yesterday
and they were starting to run tan so I went .063
and I think I will stay there.
.060 With the MSD was almost perfict.
When your plugs run a nice tan color on the white
insulator you know your running good
Larry
J&J Auto
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Mark
Forum Moderator
9/13/2003
17:49:37
| RE: Larry - MSD Ignition?
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Message:
Larry, thanks a lot. Its raining today. I might try it tomorrow.
-Mark Hryckiewicz
1993 Sport RC SB 5.2L Auto
DodgeDakotas.com
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J and J Auto
GenII
9/13/2003
20:11:19
| RE: Larry - MSD Ignition?
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Message:
TuckerLudlow
The 6a and 6al are the same unit only the 6al
has a rev soft limiter that cuts a few cyls
at what ever modual you plug in rpm for.
If there cheaper go for it.
The computer on your truck will cut you at 4800
Larry
J&J Auto
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Mark
Forum Moderator
9/20/2003
21:11:48
| RE: Larry - MSD Ignition?
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Message:
Larry, Thanks for the advice on gapping. I hunted down some AP3923 plugs and gapped them to .060. Thats .025 over the factory .035 and they run great. I felt a difference right out of the garage. I have heard from others that the MSD gives no HP boost but mine seems to give me a difference I can feel.
-Mark Hryckiewicz
1993 Sport RC SB 5.2L Auto
DodgeDakotas.com
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J and J Auto
GenII
9/21/2003
06:41:40
| RE: Larry - MSD Ignition?
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Message:
Mark,
There is HP to be had with an aftermarket ign,
All you need to do is run a bigger gap and after
playing with many plugs and gaps found the AP3923
at .060 you could feel the performace change from
the bigger flame front.
I would say 10 hp easy and you will also get
better gas milage.
Why would a person need more volts to run the same
gap, and taking advantage of the platnium's
lower resistance and getting even a bigger gap
will help even more.
That is what the after market is made for, jumping
a bigger gap to add performance and eficancy
Larry
J&J Auto
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J and J Auto
GenII
9/21/2003
07:14:44
| RE: Larry - MSD Ignition?
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Message:
Here is a message from a MSD Tech
As you can see .060 is within there recomedations
I guess we were all missing the boat on this one
The day I puled my plugs to take a look they were
running to hot at .050 opened to .060 felt more
power and they turned tan instead of white.
You can physicly feel and hear the differance how
your motor runs
That is why I recomend the AP Platnium with a .005
over stock gap with a stock ign. with a hot coil
you can take even more advantage with a bigger gap
Dear Sir,
There is really no set gap or plug that you should run, we do not have a preference to spark plug brand, basically brand of choice. We do offer a starting point to get you started COMPRESSION SPARK PLUG GAP
up to 10.5:1 0.050"-0.060"
10.5:1-13.0:1 0.040"-0.050"
above 13.0:1 0.035"-0.045"
Open gap in 0.005" increments until best performance is obtained. The only thing we do recommend is to stay away from "hype plugs"
Thanks
MSD Tech
Larry
J&J Auto
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Wadak
Dodge Dakota
JOIN HERE
11/25/2003
01:17:47
| RE: Larry - MSD Ignition?
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Message:
Larry, I was running a search to ap3923 just to see what I could come up with. Just a comment on the difference between the MSD-5 and MSD-6a, I read at the MSD web site that the 5 is an Inductive Unit like the factory ignition systems tend to be. The 6a is definitely capacitive discharge. The 5 put out more energy than the 6a. as stated above the 6a has a higher voltage output than the 5 45000 vs 40000. After looking at Tucker's post all his information is directly from the MSD web site. My son had an MSD-5 on 5 different vehicles over the course of 5 years. It's still running on a 1993 Dodge Shadow that we sold to a friend's daughter, she loves that car. The point here, MSD has certainly proved it's reliablity to me.
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