I think I might put one on to see if that helps with the 4k+ rpm missing. What is the difference in the two and which would be best for my NA 383?


[Modified by Glock'94, 4:17 AM 3/14/2002]

 

The 6AL has a spot where you can plug in the rev-limiter "pills" (or box I guess). Other than that, I think they're the same.

 

Thats the only difference. The 6AL has a rev limiter built in.

The good thing about the 6AL is you can connect a two step limiter to it.

 

You might look into the digital 6. It costs more, but it has a dual rev-limiter built in for staging or whatever, it also has a timing retard for nitrous and a bunch of other cool things.

That's what I'll be getting some day.

 

I had a miss and considered an MSD for the fix, but I found the problem. I opened the hood with the engine running on a nice dark night. One of my plug wires was arcing. You could not see the problem in the daylight or hear any zapping sounds.

Carl

90' 6 spd
3.45 rear
350 with hooker SC, random cat, Power Effect cat back, mini-ram, K&N, high output coil, underdrive pulleys, Accel 219 cam, AFR 190 heads (milled to 58cc), full rollers 1.5, 30# injectors, Taylor wires, Dynamod HEI module, Custom PROM by Shalin, BFG KD/TA tires (awesome).

 

An MSD box or any other ignition box can improve performance but won't fix a 4k rpm miss. Something is fundamentally wrong here. Fix that and then add the box.

 

jmr302 why do you think it is not in the ignition?

Jay

 

It could be the ignition, but look at what the MSD box does. It uses the stock coil and everything to produce it's "improved" spark. So if there is an underlying problem with the ignition, simply adding the MSD won't solve it. Essentially it could make it worse.

 

I was just asking why he does not think it is in the ignition, because it sounds like it is to me, and you are right it could be the coil and many other parts.

Jay

 

Slightly deviating from actual topic but since we are comparing, how does the Accel 300+ system compare with MSD? How do both systems compare with the stock system for just a mildly modified engine (i.e., basic bolt-on mods)?

 

OK, thanks guys. I have a buddy who has one he might sell me for $75. I bought new spark plugs and will see if that fixes the miss. I haven't had a chance to run the engine in the dark yet. I need to do that as well.

I'm more worried about my 3500rpm vibration right now.

 

Jay:
The MSD ignition box just charges up the coil faster, producing a more intense spark. Unless the sparkplugs are fouled, this isn't going to cure a misfire. In fact, depending on the problem, it may make things worse. The only cure is to properly fix the stock ignition system or whatever is causing the problem, then add an MSD box.

 

The MSD-6AL does a couple good things:

1) Multiple sparks <3000, big fat capacitive discharge >3000rpm
2) Much higher primary voltage
3) Easy rev-limiter changes

Given the same coil step-up ratio, the MSD generates a much higher secondary voltage, which lets you open up plug gaps, more even combustion, less fouling. If you upgrade to a better coil, you can bump this even higher. As a point of reference, my MSD plus DUI Street/Strip coil is putting out close to 60kV as opposed to 38kV stock. Just make sure you got good wires!

 

I don't find an improvement over stock unless you are reving the engine high (6k plus) or you are using a power adder, blower or nitrous.

 

Ok, well I have a high voltage coil. It's a crane fireball. I suppose i can take it by an auto store to have it tested. Is it unheard of for a coil to only fail above a certain rpm?

I don't need any rev limiter stuff, I can do all of that through the computer very easily.

 

You can do the two step for staging with the 6AL as well, except no timing retard by digital control.

 

MSD also sells a new coil for this setup. MY system sure makes it alot easyer to start I also opend up the gaps on the plugs.