Actually, stock LT1 coils are over 50% larger than stock LS1 coils...but I was referring to GM's waste spark coils being bigger than LS1 coils.

This may surprise everyone:

Northstar waste spark coil: 540 grams (1.19 lbs)
LS1 Coil w/ Integral Driver: 288 grams (0.63 lbs)

(Note that the LS1 coil also has the added mass of a driver circuit that is not in the Northstar coil.)


So a Northstar coil is TWICE the mass as an LS1 coil. When you consider that both use similar coil designs, and are subject to similar electrical efficiencies, the difference is clear...LS1 coils have roughly HALF the energy storage capabilities of Northstar coils purely on a mass basis! Looking at charge characteristics on an oscilliscope proves it on an electrical basis!

As far as lighting off 600HP, you are only lighting off 600HP on ONE spark plug at a time in a waste spark system. The other plug is arcing during the exhaust cycle, and is not at all subject to 600HP worth of pressure. It is, in fact, basically arcing in free air!!

8-coil systems are sweet looking and perform great, but when it comes to raw energy, properly setup waste spark GM coils are tough to beat.

 

1/2 of the total spark will go to one spark plug and the other half to the other..

They both light up at the same time.. which is the point.. add that to the shorter wire like you said and you have the difference there..

Energy is still wasted and 1/2 that energy/mass goes to one side and the other half to the other regardless wether there is pressure in the cylinder or not. and this is assuming that total energy is 100% dependant on mass..

 

No, the energy is most definitely not split evenly in two...

Why?

The circuit is, electrically speaking, two resistors in series, connected to a high voltage supply. The spark plugs are essentially just resistors. However, the electrical RESISTANCE of the two plugs is different, depending on which cycle the plug is on.

When on compression, electrical resistance is high.
When on exhaust, electrical resistance is low...very low.

So if we initiate a positive charge in one coil terminal and a negative in the other, the electricity must arc between the two plugs in order to complete the circuit.

well, if one plug has low resistance (perhaps just a little more resistance than a resistor core wire), and the other has high resistance, where is the energy dissipation going to occur? At the one with high resistance!! The high resistance plug is the "hot spot" in the circuit.

Picture a household toaster over. If the electrical energy was dissipated in your house wiring feeding the toaster as much as in the fine gauge wires that heat the toast, you would have a serious house fire on your hands! The reason the toaster wires get hot is because electrical energy is being exerted there...NOT in the low resistance copper wires leading up to the toaster. the reason the electrical energy is being exerted in the fine wires is because they pose an extremely high resistance to the flow of electricity!

 

Are you an electrical engineer? Just wondering.... this is interesting since I thought that electrons, like water or anything else that has pressure, would travel the path of least resistance.

 

Exactly what I was going to say...

Another thing.. They cannot be in series... if they were in series one side will get more voltage (and less current) than the other....
Unless there is a switch for a change in path between which is going to be the first fired coil or the second... If that were so why not make them totally independent like the ls1s?

Another thing... if they were in series and what you say is correct.. If I loose 1 wire I automatically loose its neighbor spark... since they are in series... and that doesn't happen, now does it?

I guess that its a bit cheaper to have 2 plugs per coil since it will be one of everything with 2 outputs and 2 separate circuits which doesn't add much to the cost... Its still better than the LT1 system and since it can be implemented in more systems, costs come down.

and as said by Bob (LTCC) from this thread or another.. The ls1 pcm has a limitation in dwell time to produce a spark. with the LTCC that doesn't happen.

I would love to see a complete removal of the opti in exchange for the cam sensor.. but.. then you get this.. 94 cars hace one opti 95 up have another which adds to the cost of research and development unless you do an opti conversion. In which case why not leave it like it is with the lTCC?

 

Yes, waste spark plugs are in series.

Depending on spark plug loading and engine/coil grounding, yes, the removal of one wire in a waste spark can stop the other spark plug from firing.

Yes, I am a degreed Mechanical engineer, and have taken electrical engineering classes.

Electricity always travels the path of least resistance! However, in a series circuit, it is forced to travel through the circuit or arc internally to the voltage source (inside the coil). Since the coil is made with extemely high dielectric material, this does not happen (unless you get a crack in the coil encapsulent material).

SO, since the current must flow through the circuit, and there is an extremely high resistive element in the circuit, massive amounts of energy (heat, light, etc...) are dissipated there!

On a waste spark, one spark plug has a "positive" center electrode, while the mate spark plug has a "negative" center electrode. Since electricity flows from + to -, one plug gets build-up of material on the side electrode, while the other gets removal of material from the side electrode.

In fact, most OEM's using waste spark (Ford in particular) actually spec two different part numbers for the spark plugs from the factory. One plug has a platinum side electrode, and one does not. I wouldn't have believed it if I hadn't seen it myself...

The reason they do this is that the platinum is only needed on the side electrode of the plug with a negative center electrode. So they save a nickel in platinum...

Anyway, that is way more than my $0.02 on the subject...I don't want to start any arguments here. I just wanted to clear up some commonly held misconceptions about waste-spark ignitions.

 

IIRC current flows from - to + and when you remove a spark plug or wire from one cable, the other cable of the same coil keeps firing... no matter which one you remove..

 

There are some new pictures on my website of the completed Delteq ignition system:

http://www.geek-racing.com/curt/ignition/delteq

They're not the best; I had to take them in the garage under florescent lighting using a flash.

Like I said earlier; I don't think one system stands out as superior to the other (lost spark -vs- direct) and am glad HOZZ4 stepped in to clear a few things up (although some of it seems to be getting lost in translation). When it came to a new ignition system for my setup, I went with what I felt was better suited to my needs.

The "why did they reinvent the wheel" argument is at best, weak(not that it was ground breaking; direct ignition has been around for awhile). DIS solutions were around when the LTx was built, but GM decided to go with a modified distributer setup with a single coil. Just because that's the way GM did it, does not mean that they were doing it for the right reasons. The Optispark was clearly a packaging/cost solution, as I believe is the case with the LSx configuration. GM still uses lost spark setups on many of their cars today as do many other engine manufacturers.

 

Ford is also using coil on plug setup for their v8s!

The why reinvent the wheel is not a weak argument from what i read on it, and... You said it correctly... "I". Its the most important thing.. because what "I" feel is what "I" believe.. its like H-beam vs I beam rods.. heck.. 4 cylinder vs 8 cylinder and turbo vs supercharger...

I guess its all a matter of preferene.. but lets say then that the lt1 is better than the ls1 because since gm chose the coil on plug they did it because of packaging reasons and not because it was a better move... so the same thing applies to the ls1, in which case GMshould have sticked teh northstar in the corvette in 1997 and the same in the 98 for the camaro

 

Nice setup man, very clean. Where'd you get those billet wirelooms from? Do they just screw on top of those bolts from MBA?

 

Lets stay on the main topic here people Thanks.

 

R&M center bolt looms from Summit Racing. Yes, they just sit on top of the MBA buttons, but you have to use a longer bolt. I ordered stainless steel Allen-head bolts from McMaster Carr.

 

I haven' been using an opti for over a year. I am using accel DFI with a HEI dual sync Distributor. Only problem is if I have to pull the Distributor I have to drop the Engine. so far I haven't had any problems.
My engine builder has also thought of a way to go without a distributor all together

 

cody could you post some pics of your setup

 

Curt,

I'm wondering, are you using the stage one or stage two kit which supposedly eliminates the opti completely??