Your son has a great resume, but niether you nor your son understand what is being discussed here or you (he) wouldn't be so motivated to spend money on a system that will provide nothing that the stock system can't (for the application). Intake tubes and exhaust are FAR from heavy mods, and the car is in no need of ignition upgrades. Chevyguy stated that he installed the system on a truck, and it "performed well from the get go". That's great, but so would have a stock system, for way less money.

He asked for opinions in the first post. I'm with the "camp" that says that all that MSD stuff is a complete and total waste of moeny. That same money would buy a cam (and more) and that is a mod that actaully WOULD make a difference. A big one.

 

I've had more problems w/aftermarket ignitions than ALL the stock HEI systems I've ever owned.

 

If you have already swallowed the hype of the self serving advertising, why the post? We need to talk about this bridge I have for sale in the Brooklyn area.

Here are some facts. None of all that pretty red "stuff" is going to give you a hotter spark. It is a principle of the Kettering ignition system that the coil will only develop the voltage necessary to jump the plug gap. The voltage requirement increases with cylinder pressure. The stock HEI is capable of making much more voltage than any L98, TPI, based engine could ever demand. Even if the MSD is capable of double (no way) the spark of the HEI, neither will produce more than the demand. Therefore all you get from the baubles is an increase in eyewash, not in performance.

RACE ON!!!

 

demand?

What notifies the HEI is has a demand?
I think what you wrote CFI is confusing me.
Particularly "neither will produce more then the demand."

 

It's not that confusing;

It takes a x amount of voltage to jump a gap of y distance, under z cylinder pressure. No amount of "potential" voltage available will change the actual votage jumping the gap in a given system.

What "informs" the coil, as you put it, are the laws of electricity and resistance. A gap of a known dimension requires a certain amount of voltage to jump that gap, and no more. Increasing pressure will increase the resistance, and therefore the voltage requirement. You can see this on an ociliscope quite clearly; a car only uses about 5k volts at idle to jump that gap. Doesn't matter that the coil COULD produce 10 times the power (if it had to)...the electricity is going to jump that gap, as soon as it can. At WOT that requirement may increase to 10k volts, due to increased cylinder pressure. An HEI coil is capable of producing over 50k volts...so how is a different coil going to help?

An analogy (perhaps not a great one though) would be the fuel volume pumped on your car. You COULD put in a pump that pumps 1000 gallons per hour, but the engine isn't going to use an ounce more fuel than it did w/the stock pump. Same goes for same goes for "giga coils". Waste of money.

 

What he said.

The MSD, when working properly, IS capable of a higher voltage spark than a stock ignition. However the headroom, the safety factor with the HEI, is so great that nothing close to stock will exceed the capabilities of the HEI.

Let's say the HEI has a max output capability of 50,000 volts.
Let's say the MSD has a max output capability of 70,000 volts.

If the cylinder conditions demand 10,000 volts, neither system will "generate" one volt more than the necessary 10,000 volts.

Remember, it is as simple as, the spark plug goes, "ZAP" and the A/F mixture goes, "BANG".

RACE ON!!!

 

I didn't mean to confuse. Sometimes I assume too much. This is not a unique property of the HEI. It is an inherent principle of an inductive coil ignition system.

RACE ON!!!

 

It is perfectly clear now. Thanks for the explanation.

Any input on the MSD mutiple discharges under 3K rpms?

 

I understand part of the confusion now. People are assuming the ignition mods are the only thing being considered. That is not the case. The ignition mods are the start of a number of upgrades. A cam, roller rockers and some head work is planned as well. Some of you people need to take a chill pill. CF is all about fun with the cars last I checked and I have been here a long time. If I give someone advice and they disregard it I dont take it personally. I shrug and move on.

 

So MY final comment on this will be..

Its a start to many mods I will be doing, when I said It performed well on my truck, I didn't say it performed "as well as stock" did I? anyway, when you put this type of stuff on, it gives you the opportunity to make your plug Gap Greater. which introduces More Volume of Spark to the cylinder, while your getting a Stronger spark and faster at the same time. In turn makes sure all of that fuel is used to its Full potential, giving you maximum performance capable of that System and motor. And I KNOW it works because ive used it, and ive seen what it can do!

Ive pulled one of the wires off of my dist Cap and watched it jump at Least 2 1/2-3"! My friend has a 70's VW Bug bone stock with Only an MSD Ign Box and it did the Same thing.. Im sorry Ive never seen a stock system do that!

 

I run a MSD Cap & Rotor with 8.5 wires, on my stock distributor. Been on there about 4 years, and I have long-tube headers too. I probably should change them out, but they're working fine. They're all Red... and I think they're pretty.

 

I understand that its only the beginning. I'd still tell him to save his money.


None of these will require these ignition upgrades either.

He will have to ditch the TPI-style intake in favor of a HSR or MR system to really see any benefits from going to a full ignition system upgrade....and even then probably not much unless he was building a 7-8000rpm monster.

 

It may only take 10-12kV at the plug to jump the gap under ideal conditions- perfectly homogenous mixture, gap that hasn't opened up, not too much crap on the electrode. Of course it all starts with that 20 year old ignition module, which is dropping primary voltage to the coil as it gets hot. Then the coil secondary output goes thru the wornout carbon contact to the distributor rotor and has to jump the gap to the cap, which is hopefully phased perfectly with the magnetic triggering ring. From the distrbutor cap, it travels down old wires that have been baked for years by the headers, and kinked because the plastic separators broke. And hopefully you remembered your dielectric grease so there's no oxidation to drop voltage from the wire to the plug electrode. You may not need it, but starting with extra voltage available is nice insurance.

What nobody's mentioned is what happens after the spark jumps the gap. Compared to the factory inductive system, an aftermarket capacitive discharge ignition supplies more current for a big fat spark, plus much longer spark duration (and multiple sparks at lower rpm, ). It blows away the oem ignition in terms of total spark energy (in Joules). Again, you may not need it; but you'll never worry about the ignition as you start modifying your engine.

My Accel system is spec'd for 48kV at the coil secondary, pushing it with almost half an amp of current. At 6000rpm, it will light off a dense fuel/air charge resulting from 14psi of boost, across a plug gap of .055".

You may not need all that, but my Accel kit was uner $200 from Summit; and if nothing else, installing an aftermarket ignition means all the parts are NEW and in perfect working order.

-George

 

The above is a repost, did you miss it? There are no dyno results showing a gain from your fat spark. Since you have used it and have seen the gains, please post some evidence.

 

So how do we measure throttle response? Is that on the dyno graph somewhere? Not on any of mine. I have it, and you notice a lack of response from unhooking it, which I have done. So, right, it gives no power, but IMO, which may be insufficient for most despite me doing my own mods in my sig, it gives better throttle response. That may be the manifestation of the fat spark. Oh, and the track? How deep into factors are you gonna go if it doesn't increase 60' times on a stick? Too much driver error involved. I'll have to see if indeed it is track-testable....

 

keep it civil or be gone.....

 

this has been some very interesting reading. well, more funny than interesting. lets all let this one die and move on to someting else. by the way. i have an msd 6al and all the other goodies under my hood. lol

 

Since you are dead set on one, there was a used one for sale for cheap on camaroz28.com the other day. I think they were selling a coil too, not sure.