XIM COP, BB COP, distributer, what works best

[kidglok]

I would not say its not that important. If a cylinder is running hotter than the others you could pull timing to keep it from detonating. For many reasons most engines the V-6 included do not run with balanced cylinders. If you can read the plugs you can quickly determine the hotter holes and adjust accordingly.

us slower guys

 

[SAMBALLS1]

I would not say its not that important. If a cylinder is running hotter than the others you could pull timing to keep it from detonating. For many reasons most engines the V-6 included do not run with balanced cylinders. If you can read the plugs you can quickly determine the hotter holes and adjust accordingly.

You would need numeric data to make adjustments accordingly.
Reading a plug is a guesstimation at best wouldn't you agree?

For example individual cylinder exhaust temperature monitoring.

That would be in my personal opinion the best numeric data you could get to make an educated decision on what the true values must be to make adjustments accordingly


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[Mike E]

The distributor (as long as your running sequential) allows individual cylinder control also. I would have to check, but I'm pretty sure there is at least a 40* range where the distributor phasing works (at least with my MSD belt drive dist.).

 

[lazaris]

You would need numeric data to make adjustments accordingly.
Reading a plug is a guesstimation at best wouldn't you agree?

For example individual cylinder exhaust temperature monitoring.

That would be in my personal opinion the best numeric data you could get to make an educated decision on what the true values must be to make adjustments accordingly


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IF your experienced, reading the plug is your best information on whats going on inside the cylinder. EGT while it is a useful tool, it is not as accurate. Example: you lower you timing your EGT goes up, but heat in the chamber goes down.

 

[lazaris]

The distributor (as long as your running sequential) allows individual cylinder control also. I would have to check, but I'm pretty sure there is at least a 40* range where the distributor phasing works (at least with my MSD belt drive dist.).

Mike, when I used a distributor I was using a 19* swing from where I was phased and I started to get some burning on the rotor from the arc jumping. I was also using a pretty powerful coil. Dont get me wrong, a distributor flat out works but like anything else there are pros and cons to each. Yes you can use a distributor for individual correction if you have the right ignition box and or aftermarket ECU.

 

[John at J&S]

Ignitions with distributor and single coil, as well as coil on plug, all fire with negative high voltage to the plug.

With waste spark ignition, half the plugs fire with negative high voltage, the other half with positive high voltage.

Has anyone reported that the three cylinders that fire "backwards" are more prone to misfire? Theory (called thermionic emission) says it's easier for electrons to jump from a hot conductor than from a cold one.

Clicking around I found this:
http://www.dragonfly75.com/motorbike/plugpolarity.txt

 

[sackracing]

I just bought a distributor setup, switching from stock ignition. Do most of you use the XFI for two step control? The 7al box that came with it does not have built in two step.

 

[turbobitt]

Ignitions with distributor and single coil, as well as coil on plug, all fire with negative high voltage to the plug.

With waste spark ignition, half the plugs fire with negative high voltage, the other half with positive high voltage.

Has anyone reported that the three cylinders that fire "backwards" are more prone to misfire? Theory (called thermionic emission) says it's easier for electrons to jump from a hot conductor than from a cold one.

Clicking around I found this:
http://www.dragonfly75.com/motorbike/plugpolarity.txt

It's funny you bring this up. I have a story to tell.....
Because of the orientation of my coil pack and a mistake initially made by mounting the pack 180 off on the ignition module, I had corrected the coil pack orientation but my wires wouldn't reach the corrected positions. My solution was to swap the wires from 1 to 4, 2 to 5, 3 to 6 such that the numbers don't match the cylinder designation on the pack but are on the same shared pair. I never thought this would matter since each individual coil has a common ground and a unique power. This tells me it fires one plug in one polarity and the other plug in the opposite polarity but for all cycles.
So to answer your question.... No. Still successfully ran 8's with waste spark.
AG


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[John at J&S]

In other words, the cylinders that were previously firing on negative high voltage are now firing on positive high voltage, and vice versa.

I remember reading about the new Holley EFI. They claim for waste spark it has more dwell on half the cylinders to compensate for reduced energy due to the thermionic effect. Don't know if this is true, but it could be done.

 

[turbobitt]

In other words, the cylinders that were previously firing on negative high voltage are now firing on positive high voltage, and vice versa.

No, because of the way the coil pack is hard wired, it fires in the same polarity all the time so the same cylinders will always be firing in reverse polarity. In order to switch polarity the coil pack couldn't utilize a common ground on one leg of each of the three coil pack terminals.
AG
Edit- after rereading your response I'm not sure if I responded correctly. So yes the cylinders are swapped for polarity but the actual coil pack can't electronically switch polarity for the power stroke vs waste .

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[John at J&S]

While searching last night, I found a reference that said the thermionic effect was worth about 1kv:
http://www.vansairforce.com/community/showthread.php?p=158750#post158750

In their example they figure a 2kv difference. Not very much, but it should be easy to verify with an ignition analyzer scope.

 

[Chrisk]

XIM is the worst ignition system out there. Zero support. Total fraud.