My MSD 6AL Box went bad and I have been running w/o it; I cannot tell any difference in performance at all; I would like to hear from those who have gone with it and w/o and your experiences if you are running modified cars like mine.

Thanks in advance...

 

Technically unless you have a performance engine that needs the double spark to burn a lot of fuel they are not of any benifit.
The stock Ign. has built in overkill in it already.

It would only be noticeable in a all out power situation.
I have a Forged 383 with over 400HP and run one but till I put the boost on it's not needed.
Serves as a great rev limiter though.
I run a 6200 even with high rev kit and big springs.

 

If you are making more top-end power, and generally like to shift above 6,000 RPMs, then a MSD box is a worthwhile addition.
Definitely a good idea on most forced induction engines (combined with other appropriate ignition changes).
The stock, Opti based ignition, is quite 'powerful', and fairly accurate by design. But it struggles when approaching 6,500 RPMs, partly due to the small sized coil. The improved upon version of GM's HEI is adequate for a stock single coil system and reliable in its simplicity, but can be slightly erratic and loose energy at higher RPMs. From an electrical standpoint, both systems are relatively 'light-duty' for the amount of voltage they are required to create, conduct, and transfer into useable spark energy. These shortcomings can be partially remedied by adding a MSD box and a larger 'normal' sized coil. Some may consider this to be a 'band-aid' fix (in lieu of a complete ignition upgrade), but it has worked well for many high powered LTx/TPI combos.
There is the potential of shortening the life of your Opti, when pushing for higher output. Although, as most of us have realized, the Opti has become somewhat of a regular maintenance item, anyway. The HEI has the advantage of having some tune-ability with aftermarket units, but should be addressed as a system, and as a whole.
Regardless, for high HP/high RPM engines (race or street), the cost of a MSD 6A, and most other basic ignition components/upgrades, is cheap insurance for making sure you are getting as close to optimal spark performance as possible.

 

I'm putting 360hp at the wheels and I have had the MSD 6al box installed when the motor was rebuilt and installed in the car, so this is the first time I have had to run the car w/o it in its current set up. I usually shift out at 6,000 rpm anyway and at this level of rpm, I have noticed no detonation or any other ignition/spark related issue w/o the box; granted I am still running a MSD coil, cap and rotor...just want to be careful since the engine is balanced/blueprinted with some nice internals....I guess I will send the box off to be rebuilt; a little disappointed in its short life!:

was installed in 2004 with the engine rebuild.....

 

If it continues to be a problem, you could probably live without it. Using good plugs with conservative gaps, and optimizing your timing/tune with what you have and the fuel you use, you could still make decent power without hurting your engine.
Since you have it, and you're wired for it, I would give it one more chance as part of your combo.

FYI: In the past, when actually speaking with MSD's tech/help line, I have experienced some 'not-so-helpful' tech/answers. However, I still believe them to be the #1 provider of ignition components for our cars. I certainly understand your frustration with your fairly new box, as I would be upset, too.

 

This is exactly why I sold the new box I'd bought, without having completed the install. My trusted expert, a longtime superb Corvette shop owner and Vette owner/enthusiast told me exactly what 500hp said: unless you are running a boosted engine or running over 7000 rpm, the HEI is more than adequate. He also mentioned problems with them.

I've had a number of issues with the engine swap that made my Vette become known as 'The Beast', but ignition was never one of them. My chip includes a 6300 RPM fuel shutoff, which is 'soft' and the car pulls hard right up to it... again and again and again.

 

I have one in my stock 91 but i just wanted a good rev limiter

 

Energy is the key ingredient to look for in a good ignition system. Without knowing what each system actually delivers, we're all just relying on guesswork.

 

I would not use any MSD Box in any car. I've heard (and probably many of you too) that they fail too often. I'd get a Mini VIP (Voltage Intensive Power) instead (see site below). And that's exactly what I did. Before I did my due diligence, I told my builder that I wanted him to install a MSD Box and he refused. He explained why he wouldn't install it and when I did the research, I found that many people who installed one were left dissatisfied as the boxes simply "crapped out."

My builder told me that instead of using a MSD Box in my car, he would install a Mini VIP as he has had excellent results with them. I certainly would not try to tell you what to do or what to install or what not to install, but I will offer my opinion as to what I believe would be your best option in this instance. Since your MSD Box crapped out (no surprise there), I'd replace it with a Mini VIP unit.

Just remember that any of these devices (whether it be a MSD Box, Mini VIP, etc.) will more than likely do absolutely nothing for your car's performance, power, etc. unless your car has been modified. My definition of the word, "modified" does not mean the usage of an airfoil or a buy it in the mail $99 chip. My usage of "modified" is a stroked engine, new cam and heads, etc. An OEM vehicle will undoubtedly fail to benefit from the addition of a Mini VIP (or even a MSD Box) unless the car's power was modified.

http://www.performancedistributors.com/minivipss.htm

 

80 500 horse If I were you I would think about that again.
MSD has been around a long time and is in virtually every race car and a heck of alot of street and custom cars out there.
I just went to the Goodguys Car show with over 2,000 cars and every one had a MSD unit not one VIP.

If they were that bad I'm sure the VIP which I have never heard of would be out there too.
I have a spare and when my wiring harness got on my long tube header and grounded out I just knew the MSD unit had the weenie.
Nope blew a coil fuse but Blaster coil and MSD 6A both survived.
They will repair defective units as will others but as many MSD units as there are out there and the tiny number of failures among those I would say MSD was the leader and is still the leader.
That said I wonder if they are now made in China along with everything else in this country.
I have a spare that is older than my 95 car and still works fine.
You can promote VIP because it is recommended , thats cool but trashing the leader to promote it just ain't fair.
My electrical gremlins have all been the cheap Chinese electrical connections I have been using.
I need to find some better connectors and soldier the $hit out of them.
I'm one of those guys who likes to keep spares and change parts to diacnose gremlins so I have connectors for easy change out.
Going to have to rethink that again or find better quality connectors.
I accually can't find any good quality Platnum or copper connectors anymore, only cheap ones.
Not so great for performance applications.

 

I have no connection with VIP, or any experience with their products. I will say though, there is an electrical/physics reason for considering the premise of their product. The energy in inductive ignition systems is determined, as I mentioned in an earlier post, by the coil specs (primarily its inductance) and the current passing through the coil at the time of end of dwell. Charging a coil takes time (hence dwell time or period). At higher RPMs there is less dwell time available. The general result is less coil charging, resulting in less energy stored into the coil. For most engines, the hi-RPM reduction in coil energy is not a big deal. For hi-perf engines (with high C.R., high V.E., super/turbocharged, etc) that require high energy levels at these higher RPMs, something must be done to allow the coil to charge up quicker. A lower inductance coil will charge up quicker (although one may not be easily available or easy to package in the original distributor), or one can bump up the supply voltage to the coil to force more current into it in a shorter period of time. Jumping from 12 volts to 18 volts will theoretically increase the primary current by 50% in that same short dwell time. A 50% increase in primary current will increase the coil energy by over 100% (doing the math in my head, here). A quick easy way to increase high RPM spark energy.
Now, the down side. The coil (and possibly, module, depending on how the owner hooks things up), will be working under higher voltage conditions (obviously) while hooked up to an 18 volt source. This results in increased wattage dissipated in the coil (and module), not good for long term durability. For quarter mile usage, it's not a big deal. For endurance racing, there could be problems with long term ignition reliability.

 

I don't see anything in your combo that tells me you should really use one. I had one on a turbo car and it failed all the time.

 

I greatly prefer a multi-coil inductive ignition system over any capacitive discharge ignition systems -- this allows for more dwell time per coil without the damaging effects.
My experience with capacitive discharge ignition systems is most have way too short pulse duration -- some of them use multi-spark to attempt to make up for the short pulse.

Cold weather (below zero F) starting can be a problem with capacitive discharge systems because of the short spark duration.

Tom Piper

 

I appreciate the input from all of you.....I guess I've learned....the reason why I bought in the first place was the TPIS catalog (where alot of my parts came from) indicating in bold letters......If you are making power over 4000RPM (which I am with my setup), you must have an MSD ignition system....I may not need it after all....