I know alot of guru's are in here that study motor physics and what not. I enjoy reading this forum and have an advanced question. A friend of mine and me were discussing about spark plug wire length.
I hear that voltage can lose some of its charge over a period of length. On an lt1 motor some of the spark plug wire lengths are near 1 ft. and others are near 3 ft. Could this cause any type of spark loss? I am not talking about noticeable amounts of loss or performance loss, Just in general could it be losing some voltage?
I know all of the ls1's have the same wire length for every cylinder, could this in some way be better vs. the lt1 style. Now once again I'm not talking in performance gains or anything like that. Just general question as could it?
Thanks
-Joseph

 

It take roughly 30,000 volts to jump a plug gap. The current is extremely small. The resistance of the wires used in these cars is very small, some as low as 50ohms/ft. Voltage loss = amps X resistance. Hence the voltage drop in the wires is insignificant relative to the voltage required to fire the plugs, and the differences in wire length are insignificant.

 

So, from what you are saying, is that the travel of voltage will be the same in a one foot of wire, as compared to three feet???? 50 ohms< 150 ohms..

As far as time from the distributor to the electrode(plug), would you want the shortest distanced traveled??? Hence a shorter wire...

 

First I said that the loss of voltage (current in the wire X resistance of the wire) is different in each wire, but is just a tiny portion of the 30,000 volts that are required to jump the gap.

But the electric charge travels at the speed of light.... or fast enough that the difference in time required to travel a 3-ft wire compared to a 1-ft wire would not be measureable..... e.g. its not going to affect your ignition timing.

 

Wont the longer wires create more capacitance at high RPM?

With the voltage field rising and falling at such a high rate, will that alter the
voltage peak?

With a constant DC, it's not so much an issue. With the 'switching' on and off,
will that cause the spark to die at higher RPM?

I'm just thinking along the lines of AC circuit reactance. Although the wires
will never see an opposing phase, will there be a "damping" effect?

 

....spark plug wire length has nothing to do with the efficiency of the what reaches the gap. Just use a very good set of plugs and wires and ignition source and you can't go wrong !!

 

I wouldn't go that far.

Wire length in the case of high output ignitions with variances of 1 ft. to 2 ft.
may have little effect overall, but extra length in the truest sense will degrade
signal quality.

As a charge travels further down a wire it looses many of the characteristics
it started with.

If you were to scope the input of the wire against the output side (plug end),
you would see a drop in amplitude, some damping, and even phase shifts.

All of the above will be more apparent at higher RPM. Whether it tends to promote
misfires (longer wires) is beyond me. I'm led to believe the coil saturation/recovery
is more of an issue than wire length in an single coil system.

 

True but my point was only ....use a good set of plugs and wires and use a proven ignition system and you can't go wrong. This would be true for the average or slightly above average racer.
Now if some dumb@ss goes and makes his own custom length wires and adds 4 feet to his wires just to prove a point; then I think that's rediculous! Sure, performance might drop but who the heck would do that on purpose?

 

If you've looked through this thread and wondered why there are so many deleted posts, I'll just say it was an unfortunate incident where a relatively new member (sluggoz28 - 30 posts) decided he didn't like me or my tech responses and launched a personal attack. The board Administrators saw it, and said if it happened again, he's history. In the end, he repeated the attacks in another thread. He his no longer with us.

I really have no problem with anyone arguing with my posts, thoughts, tech advice, etc..... I realize when I post something, it is open to criticism and correction, and I welcome mature responses. But when it becomes a mindless personal attack, not dealing with the tech issues, I have little choice but to delete the posts.... NOT because they attacked me, but because they seriously dimished the stature of this board.

In all honesty, I have no idea who sluggoz28 was, or why he decided he didn't like me, and I don't really care.