Msd?
Thread Starter
Drifting
Joined: Dec 2005
Posts: 1,313
Likes: 2
From: High Ridge Missouri
Msd?
At what point do you guys think MSD (or any other type of multiple spark ) ignition system is necessary? I understand on a car running juice or a boosted application it's necessary because of the elevated cylinder pressures, but when to put it on NA car?
Race Director
Joined: Nov 2003
Posts: 12,220
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
From what I've read, it's unnecessary and unreliable. Many MSD-6A units have been returned/failed. Also, you are planning to run an SLP/TPI which I consider a mechanical rev-limiter! 
(Seriously, there some truth to that.)
Also, I recently read where multi-spark ignition systems can fool the knock-sensor into thinking there's a problem. And, it might retard the timing when you don't want it to.
With a modern high-energy EFI system like you'll be running, I don't see any circumstance where you'd need to add one. Just pick good wires and plugs (keep your cap/rotor fresh) and you're good to go.
BTW: Getting a good tune (or even dyno tune) would be a better use of that money IMO.
gp
(Seriously, there some truth to that.)Also, I recently read where multi-spark ignition systems can fool the knock-sensor into thinking there's a problem. And, it might retard the timing when you don't want it to.
With a modern high-energy EFI system like you'll be running, I don't see any circumstance where you'd need to add one. Just pick good wires and plugs (keep your cap/rotor fresh) and you're good to go.
BTW: Getting a good tune (or even dyno tune) would be a better use of that money IMO.
gp
Drifting
Joined: Jan 2005
Posts: 1,350
Likes: 322
From: San Antonio Tx
I installed a MSD 6-A and could not tell any difference. The stock ingition will spin my motor to 6150 rpm's with no problem. I installed it to see if it would improve the idle or gas milage. Didn't make any difference.
Thread Starter
Drifting
Joined: Dec 2005
Posts: 1,313
Likes: 2
From: High Ridge Missouri
Hey Gregg
This wasn't really concerning my car, it was more just for common knowledge. As far as the reliability of the components, believe me I know how bad it can be first hand.
I'm just curious at what ponit are they necessary on a NA application?
From what I've read/researched:
As far as high RPMs being a factor, that shouldn't be it, because once you hit in excess of (I want to say) 5500rpm the spark is hitting so fast there is no time for multiple spark. So MSD is actually used at lower RPM as opposed to necessarily being needed on high revers.
This wasn't really concerning my car, it was more just for common knowledge. As far as the reliability of the components, believe me I know how bad it can be first hand.
I'm just curious at what ponit are they necessary on a NA application?
From what I've read/researched:
As far as high RPMs being a factor, that shouldn't be it, because once you hit in excess of (I want to say) 5500rpm the spark is hitting so fast there is no time for multiple spark. So MSD is actually used at lower RPM as opposed to necessarily being needed on high revers.
Advanced
Joined: Apr 2005
Posts: 77
Likes: 0
From: South Brunswick New Jersey
From a performance prospective, you will most likely feel nothing. However, I became a believer years ago when I had an Isuzu p'up. The truck would stall on occasions, but once I installed a used msd 5, it ran like a champ. When I removed the system just before junking it, the stalling came back. I'm running a Mallory 6 unit in my car now because I got a deal on it, but same principle. What you will notice the most is a smoother idle. For me, I feel the motor is running more efficient.
Melting Slicks
Joined: Apr 2007
Posts: 2,616
Likes: 111
From what I've read, it's unnecessary and unreliable. Many MSD-6A units have been returned/failed. Also, you are planning to run an SLP/TPI which I consider a mechanical rev-limiter! (Seriously, there some truth to that.)
Also, I recently read where multi-spark ignition systems can fool the knock-sensor into thinking there's a problem. And, it might retard the timing when you don't want it to.
With a modern high-energy EFI system like you'll be running, I don't see any circumstance where you'd need to add one. Just pick good wires and plugs (keep your cap/rotor fresh) and you're good to go.
BTW: Getting a good tune (or even dyno tune) would be a better use of that money IMO.
gp
(Seriously, there some truth to that.)Also, I recently read where multi-spark ignition systems can fool the knock-sensor into thinking there's a problem. And, it might retard the timing when you don't want it to.
With a modern high-energy EFI system like you'll be running, I don't see any circumstance where you'd need to add one. Just pick good wires and plugs (keep your cap/rotor fresh) and you're good to go.
BTW: Getting a good tune (or even dyno tune) would be a better use of that money IMO.
gp
Well I agree,
I can tell you from first hand experience since I installed the 6AL box the same time my newly rebuilt engine with all of the mods. you see listed here went into the car.....last year, the box quit....this box probably has about 5,xxx miles on it, tops....the car would not start one day and we bypassed the box....fired right up..lasted a couple of years on a car that is driven on nice days/evenings only....basically a garage queen......after a couple of spirited driving moments putting the engine through the paces (and this engine revs to 6,xxx RPM with no problem) I cannot tell a difference in performance whatsoever....NONE.....the only reason I purchased it, was because TPIS highly recommended in their catalog....reads "if you make power over 4,500 RPM, you must run an MSD ignition 6AL"..........not so if you have a good cap/rotor/wires/plugs.....I am running Taylor wires with Bosch +4 plugs with a new MSD cap/rotor as well......the 6AL box is junk in my opinion.....now I have a box in the car that is shorted...need to have removed...
one more thing.....my mechanic tested the box...it's shot
Last edited by 856SPEED; May 23, 2009 at 09:07 AM.
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